JPH02653B2 - - Google Patents

Description

[Detailed description of the invention]

Perishable items must be kept within a specific temperature range during transport to avoid melting, freezing, or delaying or preventing ripening. To ensure the quality of the goods, it is standard practice to monitor and record the temperature of the goods during transport. Typically, a circular chart temperature recorder is
It is used to record the temperature within the conditioned space during transport. This device provides a record only of the temperature of the conditioned space measured at the outlet of the evaporator, and this record is removed from the container upon removal of the paper chart. Additionally, data can be lost due to failure of the clock mechanism, chart, recording pen, and ink. The data itself tends to be highly compressed due to the physical limitations of space as it records temperatures over long periods of time. The present invention seeks to replace temperature indicator recorders that use circular charts. More particularly, the present invention seeks to replace mechanical chart recorders with electronic data loggers and store temperature data for later recall by an interrogator/printer or through a display and keyboard. Electronic data recorder -30,5℃~+30.5℃
is an indication recorder for two temperatures within the range of . This data recorder also records and indicates the setpoint temperature from the temperature controller as well as the regulator defrost signal. Power interruptions to the recorder and the duration of interruptions are also recorded. The recorded data is transferred to the recorder.
It may be displayed using an auxiliary keyboard that is part of the keyboard. External connections also allow monitoring of the regulator's active temperature probe signal via the display. An auxiliary control function monitors the supply air temperature and provides an alarm when the supply air temperature remains 3° C. below the set point for a period of 20 minutes with respect to the set point within the salvageable temperature range. This low temperature alarm also activates an interlock that is used to control the monitored refrigeration system and to activate a remote alarm. A data retrieval and display device called an interrogator/printer is provided to create a document that can be followed by a human in place of the charts from commonly used chart recorders. The interrogator/printer is used for all functions other than warning writing and data analysis normally performed by an operator or clerk to verify refrigeration system performance.
It also has auxiliary functions for data inspection. It is an object of the present invention to provide a method and apparatus for measuring temperature data and storing its values for later recall. Another object of the invention is to allow independent verification of container return and/or supply air temperature. Another object of the invention is to provide a temperature data recorder with an expanded operating temperature range and improved data accuracy and clarity. Another object of the invention is to record the actual values of set points, monitor the performance of the refrigeration equipment, and record events related to temperature regulation/equipment operation, including the occurrence and duration of power interruptions. The purpose is to provide a data recorder. Another object of the invention is to provide a device which avoids the problems associated with clock mechanisms, charts, pens and ink required for mechanical recording. Another object of the invention is to be able to obtain additional information from temperature data. Another object of the invention is to provide an apparatus for providing temperature information to an interrogator/printer without loss of data from memory. Another object of the invention is to provide an apparatus for retrieving and processing data and providing a hard copy of the processed data. Another object of the invention is to provide a recorder that retains data in memory until it is replaced by new data. The above and other objects are achieved by the present invention, as will be made clear below. Basically, the invention is directed to an electronic temperature data recorder having electronic memory and control circuitry for temperature and event acquisition, display and storage.
The acquired data is stored in a manner that allows chronological playback for display and/or transfer to other storage media. The device records multiple temperatures, set points and multiple discrete events at time intervals to provide a history of temperatures and related events. Typical temperatures and events that are stored are supply air temperature, return air temperature, thaw occurrences, power outage occurrences, and regulator set point temperatures. The stored information is retrieved from the recorder by an interrogator/printer, which provides a processed hard copy of the retrieved data. The invention will be explained in more detail below with reference to embodiments shown in the drawings. In FIG. 1, generally designated 10 is an electronic data recorder according to the present invention, which is installed in a refrigerated container 11 for monitoring and recording the temperature and events within the container. Electronic data recorders are microprocessor-based data acquisition and processing devices. In combination with interrogator/printer 26, data recorder 10 displays, records, and prints temperatures and events typically associated with the performance of the refrigeration system (not shown) for refrigerated container 11. Recorder 10
includes a plurality of membrane keys 13 to 18, a display 19, and a plurality of display amplifiers 21 to 25.
a display panel 20 having a
It includes a control panel 12. Interrogator/printer 26 may be directly connected to recorder 10 or indirectly connected to recorder 10 through tape recorder 27 to transfer data from recorder 10 . Data can be recalled via control panel 12. Tape recorder 27 records data that could not be processed in the report. Alternatively, the output of tape recorder 27 may be connected to a computer 28 for storage and/or use;
It can also be transferred to a desired location via an offline teleprinter 29. Referring now to FIG. 2, signal interface 32 of recorder 10 receives analog signals in the form of analog voltages indicative of set point temperature, defrost, feed temperature, and bunch temperature. The signal interface also receives discrete signals in the form of open and closed switches representing on or off conditions of the input signal. These discrete signals connect signals from keys 13-18 to other on/off signals that select operating modes and functions.
off signal. The analog voltage is selected by a multiplexer and digitized in an analog-to-digital converter (A-D converter);
It is provided to control logic 34 as a discrete signal. Control logic 34 is in two-way communication with memory 36 and interrogator/printer/tape recorder interface 38 and provides output signals to display interface 40. Output signals supplied to the display interface 40 provide control and data information appearing on the display 19 and corresponding indicator lamps 21-25 relating to the data currently appearing on the display 19.
and the activation of any alarms. Interrogator/
Printer/tape recorder interface 38
The interrogator/printer or tape recorder communicates with memory 36 to receive data stored in memory 36 in chronological order in response to control signals provided from interface 38 to control logic 34. enable. Time information, which is part of control logic 34, is provided to recorder 10 by time character device 30. As best shown in FIG. 3, power supply 42 is typically powered by a battery pack 43. Power supply 42 provides electrical power for stepping down the voltage, 12V, provided by battery pack 43 to the operating voltage, 5V, required to operate the various electronic components of interrogator/printer 26. Contains an adjustment section. That is, power supply 42 detects insufficient voltage and provides a signal indicating the same. Battery pack 43 may be connected to a power source, such as a marine power source, through a charger 44 for recharging it. I/O connector 45 is a female multi-pin rack and panel style connector.
The I/O connector 45 connects to the memory 36 of the recorder 10.
Forms an external connection to the interrogator/
A connection is made between a printer 26 and/or a tape recorder 27. The interrogator/printer 26 communicates with the recorder 10.
A single parallel bidirectional channel is formed via I/O buffer 47 and control circuit 46. The strobe signal controls the timing when the output channel is from recorder 10. Data for transfer to recorder 10 is placed in I/O buffer 47 to be read by recorder 10 when called upon by interrogator/printer 26.
A data confirmation signal is generated by recorder 10 to gate data from interrogator/printer 26 onto the communication channel. A strobe signal (a normally high, negative-going pulse) accompanies the data during transfer to interrogator/printer 26. The busy signal channel to recorder 10 is connected to interrogator/printer 2.
6 is ready to receive data again.
A logic high level to indicate a busy condition on the output channel. The input channel's "data available" line is set low whenever valid input data is present on the input channel. When data is read by recorder 10, a confirmation signal is provided as a negative-going pulse, causing the "data available" signal to go from a low level to a high level. This allows input coordination of data into the recorder 10.
Within the interrogator/printer 26, the I/O connector 45 is connected to the control circuit 46 and the I/O buffer 4.
Two-way communication is carried out with a single-chip central processing unit (CPU) 48 via 7. CPU4
8 is a keyboard controller 50 and a scan decode 51
A 58-key keyboard 52 is accessed through the keyboard. Keyboard controller 50 is an integrated circuit that has the function of converting the open and closed states of contacts in the keyboard matrix into binary signals for CPU 48.
Scan decode 51 receives three signals from tape recorder controller 50 and selects one of eight rows on the keyboard. CPU 48 provides "call" and "write" signals to keyboard controller 50;
It also receives "interrupt" signals to control printing of data. “Call” “Write” and “Interrupt”
The signal is a negative true logic signal, ie O=on, 5V=off. The CPU 48 also has two-way communication with the printer mechanism 56 via the printer driving electronic circuit 55. CPU 48 directly and through address latch 64 provides program memory 60 and data access.
It is connected to memory 62. CPU 48 provides a "ring" signal directly to audible signal portion 66 and provides key control signals indirectly to audible signal portion 66 through address decode 65 . Reference numeral 70 in FIGS. 4A, 4B and 4C indicates the evaporator of the refrigeration system or temperature control device 68 for the refrigerated container 11. In FIGS. Discharge fluid from the evaporator 70 is supplied to the refrigerated container via conduit 71 and returned to the evaporator via conduit 72. Analog or signal interface portion 32 includes signal conditioning circuitry and an A-to-D converter for converting temperature and controller signals to binary data for the CPU.
The signal conditioning circuitry consists of amplifier and attenuation circuitry to match the temperature controller set point or active temperature, defrost and reference voltage signals to the range of the A-to-D converter. A passive excitation circuit and a reference divider circuit are provided for interfacing the recorder thermistor to the analog-to-digital converter. Dual 4-channel analog multiplexer (2
Pole, 4-position switch) provides one of four analog inputs (set point, defrost, supply or return) and one of two references (control unit/4 or internal accuracy x 0.8) to the analog-to-digital converter. Select as signal and reference voltage. The input signal and reference are coordinated so that the A-to-D converter can perform ratio operations that eliminate errors due to variations in the reference voltage. The temperature of the air supplied to container 11 via conduit 71 is sensed by a thermistor 74 which provides a signal to an excitation circuit 76 indicative of the temperature of the supplied air. Similarly, a thermistor 75 detects the temperature of the air returning to the evaporator from the refrigerated container 11 via conduit 72;
A signal indicating this is given to the excitation circuit 76. A multiplexer 78, which is physically part of the same element as multiplexer 79, is connected to the excitation circuit 76 for receiving signals indicative of supply and return air temperatures, and is also connected to a clamping circuit 80 and a divider 82. There is. Clamping circuit 80 receives a signal from temperature controller 68 via interface and power connector 69 indicating a refrigeration system defrost and provides a 1.5V signal to multiplexer 78 upon the occurrence of defrost. Divider 82 receives a setpoint signal indicative of the setpoint temperature selected by temperature controller 68, divides it by four, and provides it as an input to multiplexer 78. Multiplexer 78 is configured to digitize four analog input signals provided by excitation circuit 76, clamping circuit 80, and divider 82, respectively, in response to a channel selection signal provided by CPU 92 via channel selection signal line 83. Select one of the signals. The selected signal is sent to A-D by multiplexer 78.
It is applied to a converter 84 where it is digitized. A regular 2.0V reference signal is provided by circuit 86 to multiplexer 79 to provide excitation to excitation circuit 76. 9V±
A 5% reference signal is passed from the temperature control device 68 to the divider 8 via the interface and power connector 69.
8, whose divider divides the reference signal by 4 and provides the resulting signal to multiplexer 79. In response to a channel selection signal provided by CPU 92 via conductor 83,
The multiplexer 79 sends the reference signal to the A-D converter 8.
Give to 4. The A-D converter 84 sends the output signal to the CPU timer RAM via the buffer 90 and the data bus.
address latch 106, low RAM address 116, 6K×
It is connected to an 8CMOS RAM 124, a clock 130, a display control section 134, and a printer data buffer 146. Power supply 94, which is identical to power supply 42 of FIG. 3 except for its AC input, receives power from a wide range of suitable AC and DC power sources, including a battery 93 that serves as a backup energy source. for example,
Power supply section 94 is a 12~15VDC power supply or 47~63Hz
Connected to a regular 24VAC power source in the frequency range. The power supply 94 subsystem provides the operating voltage for the electronic circuitry and is derived from a 24 VAC input and 12 VDC supplied from the temperature controller 68 via the interface and power connector 69. In addition, conductor insulation is provided by a 24V/12V transformer. The 12V AC secondary voltage is rectified and filtered to remove harmonics. An electronic regulation circuit adjusts the main DC supply voltage and the operating voltage.
Maintained at 5.7VDC by a pair of diodes that isolate and step down to 5.0VDC. Internal operating voltages include a 5VDC operating supply, a 5VDC memory and clock supply, and a precision 2.5V reference. Regular 3.6V
A primary battery 93 and switching circuitry are provided to support the memory and clock when a 5V supply is not present. The low battery voltage detection circuit detects a battery voltage of 2.95VDC or higher and indicates “Battery OK”
A signal is given to the CPU 92. Input voltage monitoring circuit
12 VAC to detect improper input voltage levels and provide a "low voltage" signal to the CPU 92, which is inverted in an inverter 133 to a "non-low voltage" signal and provided to the display controller 134. . A set circuit that detects the supply of DC voltage to the logic circuits is provided to properly start the CPU 92 in a known state when power is restored. A reset circuit provides power interruption and restoration instructions. The power supply section 94 provides stable output to the component 9.
2,106,108,110,90,84,7
8, 79, 76, 86, 88, 116, 118,
124, 130, 134 and 146. Power supply 94 provides a stable output to component 1 when there is insufficient input power to maintain operation.
18, 124 and 134. More specifically, the power supply subsystem 94
(42) provides the recorder 10 with some power related to operating and reference voltages and control signals. The control signals are a "low voltage" signal, which is asserted when the input supply voltage falls below a preselected level, and a "reset" signal, which indicates the need to place the CPU 92 in a reset state. Referring now to FIG. 5, power supply 94 includes AC current transformer T1, rectifier diodes D1-5, D9 and D10, filter capacitor C, and an electronic system that provides regulated 5.7VDC power as the primary operating power source. It consists of a voltage regulator A1. The 5.7VDC power is passed through diode D7 to the main 5VDC power, V hard copy, RAM 124, real time clock 130 and RAM high address latch 1.
distributed among electronic components except 18. main
Components not powered by 5VDC are
From a 5.7VDC source through another diode D6
Receives 5VDC power, Vcmos, and alternatively
In the absence of a 5.7VDC source, it receives power from the 3.6VDC battery B1 via another diode D8. A precision monolithic voltage reference A5 provides a 2.5V signal to the input of a unity gain operational amplifier A4, which buffers this signal to produce a 2.5V signal at its output, which is the system reference voltage. Used as Vref. Operational amplifier A3 is configured as a comparator with two inputs, one input connected to a precision 2.5V DC reference and the other input connected to the voltage at the input of the voltage regulator. It is connected to a resistive/capacitive RL/CL network that samples the level and provides a signal proportional to the input voltage level. The output of operational amplifier A3 is driven to ground voltage level when the input voltage level drops to a level that is too low to maintain reliable operation, in this case 17 VAC or 11.5 VDC. At other times, the comparator output is approximately at the 5VDC level. This "low voltage" signal warns the CPU 92 of an impending power interruption and gives it sufficient operating time before loss of operating voltage Vcc to store the information necessary to perform its functions after power is restored. Therefore, it is applied to the central processor interrupt input. These parameters include storing the last recorded data time in memory and completing storage of the current record within the recording process. Capacitor C provides stored energy to the 5V supply to enable operation after loss of input power. The stored energy is blocked from the low voltage detection circuit by diode D9, allowing it to function autonomously. The low voltage signal is also provided as one of the inputs to the reset circuit. Referring to Figure 6, CPU
The reset input of 92 is shown connected to the common point of transistor Q1, diode Dr, resistor Rr, and capacitor Cr. The reset circuit operates in two modes as a result of power supply or power removal from the system. The reset circuit is connected through an RC network R _R /C _R that keeps the reset input at an active low level for a sufficient time to ensure proper startup of the CPU 92 and inhibits its operation until the supply voltage Vcc is suitable. A timed pulse is applied during power supply. Diode Dr acts to rapidly discharge _CR to ensure reset operation during short power interruptions. Transistor Q1, driven from a logic circuit consisting of gates and inverters U1-U4, operates to keep CPU 92 in reset whenever the input voltage is inadequate for proper operation. OR gate U3 becomes active due to the OR condition of the low level "low voltage" signal input and the signal from U4 inverted by U2, and the low voltage signal is input and the CPU's "reset enable" is activated.
The output of U3 will always be low when the output is also input or the output of _U3 is already low. U
The output of 3 is latched low when the low voltage signal is present and the enable signal is present at the same time. Since all CPU outputs are forced to a logic high level by the reset state, the reset enable signal will cause the CPU 92 to pull the signal low until the CPU enters the reset state, thereby removing one of the input enabling resets. Exists only when set to .
Removal of the reset enable condition allows the reset to be removed when the low voltage signal goes false. This allows CPU 92 to resume operation from the reset state. The use of this circuit allows the CPU 92 to delay reset upon detection of a power interruption to complete the necessary shutdown process, and also allows control of the reset from a low voltage input. A low voltage signal indicates the last recorded time before the completion of an activity that was terminated by a power interruption.
Guaranteed to be stored in RAM 134. Operational amplifier A6 connected as a comparator
detects the level of 5VDC power at one of its two inputs and compares that level with Vref.
The output of "switch" A6 is connected to the output enable control input of RAM high address latch 118, which places a low active signal when Vcc is above the 4V level, and the latch controls the chip select input of RAM 124. , thereby allowing data transfer to or from RAM 124 via the data bus. “Switch” A6
puts a high signal on the output enable control when Vcc is lower than 4V, which causes RAM124
disable control of the chip select signal to
It also allows RAM 124 to be disabled from data transfer and prevents changes to the data stored within RAM 124 while the supply voltage is insufficient for operation of CPU 92. The reset signal places CPU 92 in a reset state in which its data and control registers are initialized to known states. Alongside these deactivations, the program counter is set to zero. When leaving the reset state and the SET signal is removed,
CPU 92 begins executing instructions from program memory 108 at the current location of the program counter (ie, 0). The process that is executed is
This includes clearing all internal registers, including those reserved to indicate conditions that record power interruptions. This register has a value after the power loss duration calculated by subtracting the last recorded time from the current position read from clock 130 when data is to be recorded in RAM 124 after power is restored. is set. The first record stored in RAM 124 after a power interruption is information indicating the occurrence of the power interruption and information indicating the number of recording intervals that have elapsed since the data was last recorded in RAM 124. This method of measuring the duration of a power interruption allows temperature records to be reconstructed in chronological order without the need to record data during times when power is off and the refrigeration equipment is not operating. Temperature during power interruption is generally meaningless since air circulation has stopped and supply and return air temperatures cannot dictate load conditions; temperature upon power restoration and duration of power interruption are useful. . Additionally, the device may remain unpowered for extended periods of time when used to transport perishable items in one direction and non-perishable items in the other direction between two points. is normal (e.g. 15 days of operation, 15
(inoperable for days). Reserve clock 130 during power interruption
Since only RAM 124 and RAM 124 are active, battery capacity requirements are minimized and the time interval for retaining stored information is extended with a minimal number of RAM storage locations. Recorder keyboard 12', modified as shown in FIG. 7, can access data stored in RAM 124.
When the "Shift" key 14' is held down while the ℃/〓 key 18' is pressed down, the RAM 1
24 may be enabled or disabled. When enabled, the key's secondary functions are active. Enabling "recall" will display the first record after "transport start". Records are displayed with the first item in the record indicating the recording interval.
The "next item" key 17' advances the item of record to be displayed. Items included in the record include setpoint change information if the setpoint is changed within the interval, power interruption information if the interval follows a power interruption interval, and supply air temperature; Contains return air temperature and defrost signal status. Actuation of the "Next Record" key 16' will display the same item in the next record, or if the item does not exist in the next record, the record interval. The "Rapid Advance" key 15' allows the next item or next record function to be repeated by holding the selected function and the Rapid Advance key simultaneously. Display recall is performed using the interrogator/
Allows viewing of data stored in RAM 124 without printer 26. This is important in locations where an interrogator/printer is unavailable or non-functional, and also provides feedback to the operator or maintenance personnel to assess the previous operation of the refrigeration system. Electronic digital control logic circuit 34 and memory 36 are single-chip microprocessors;
614 low power random access memory (RAM)
4096 program memory locations, a real-time crystal controlled clock, and various gates and buffers that control the flow of data to and from the microprocessor.
6144 (6K) bytes of RAM store recorded data and control parameters so that they are retained throughout power interruptions. The RAM and clock are normally powered from the main 5 volt supply, but are supported by battery 93 during power interruptions. This allows the system to maintain data and time continuity. switch 11
9 detects loss of 5 volt supply and connects RAM input/
The output circuit is disabled to prevent erroneous modification of RAM contents during removal, absence, or application of control power. Microprocessor 92 is a complete computer in its own right, requiring only a power supply and a clock signal for operation. The program memory 108 is contained in a separate programmable read only memory (PROM) and has up to 4096 program instructions or data. There are 128 bytes inside the microprocessor (location).
of RAM, an 8-bit timer, and a central processing unit (CPU). Used to detect and control signals to and from the CPU
27 input/output (I/O) lines are provided.
Additional control signals adjust the timing and direction of data flow to and from the microprocessor and select the destination or source of data via external gates and buffers. RAM 124 is organized into three segments of 2048 bytes, and individual storage locations are separated by memory address latches 116 and 1.
18 by loading the specific address. The data is then transferred to the system data
It can be read or written to at that location via the bus. Clock 130, which corresponds to time interface 30 of FIG. 2, is a circuit that includes a frequency division circuit and a counter for calculating values representing real time in seconds, minutes, hours, days, and months. Counters are individually addressable and allow the CPU to obtain time information. The clock can be set to a particular time by the CPU and reset to zero time. ADC data is also addressable.
The CPU can obtain status and data via the data bus. A single bidirectional I/O buffer 146 connected to connector 150 provides access to the CPU and allows the CPU to transfer data to external devices from itself or from other devices on the data bus. do. This signal path is connected to the interrogator/
It is intended for use with a printer. This signal path can alternatively be used to transmit or display operating data remotely with the aid of external circuitry. CPU timer RAM 92 is accessed by keyboard switch matrix 102, which may include an auxiliary keyboard for displaying stored data. The CPU 92 sends panel selection signals to multiplexers 78 and 79 and “read” and “write” signals to address decode 110.
An address latch enable (ALE) signal is provided to address latch 106 and a program strobe enable signal is provided to 4K×8 program memory 108 to distinguish the program memory from other sources. Additionally, CPU9
2 has one-way communication with address latch 106, low RAM address 116 and display control unit 134, and also has 6K×
It has two-way communication with 8CMOS RAM 124, clock 130 and printer data buffer 146. Address latch 106 transfers the address signal to program memory 10 via the address bus.
8, to the display controller 134 and address decode 110. Program memory 108
The output of is provided via a data bus to the CPU 92 to provide a flow of instructions that coordinate the activities of the CPU 92 and to the peripherals to perform their functions. Address decode 110 provides a plurality of mutually exclusive and unique signals that are provided to various external devices one at a time. In particular, address decode 110 provides an A/D address signal that selects one of four digits for transfer to CPU 92 via data bus and buffer 90 and an A/D address signal that causes transfer of the selected A/D digit. /D read signal and RAM address decode signal to low FMA address 116 and high
The RAM address 118 is given to the CMOS RAM read decode signal and RAM write decode signal.
the clock I/O decode signal to the clock 130, and the I/O connector 15.
A "printer read" signal is provided to printer data buffer 146 to control the direction of buffer 146 and printer I/O connector 150 to read data from a device such as interrogator/printer 26 connected to , provides a "printer write" signal for controlling the timing of data transfer to an external device, and also provides a display write signal to the display control unit 134. Low RAM address 116 and high RAM address 118 each provide address information and data to the CMOS CPU 92 via the data bus.
Supply to RAM124. Clock 130 provides timing information to CPU 92 via a data bus. Clock 130 also receives data from CPU 92 via the data bus to initialize its state. Display controller 134 controls five-visit LED display 140 through current controller 136 and digit driver 138. Printer data buffer 146 provides data to or reads data from printer I/O connector 150 for printing by and receiving control signals from external devices. The display includes five seven segment hex indicators and five discrete light emitting diodes. All display indicators are driven by a single display controller that holds the desired display information in its memory and operates the multiplexed configuration of indicators. The four rightmost seven segment displays can point to any of the hexadecimal codes, but only three horizontal segments can be displayed within the fifth digit. The rightmost digit is inverted to allow its decimal point to be displayed as a degree indicator. The display controller, along with segment current limiting resistors and digit drivers, make up the remainder of the display subsystem. A negative true low voltage signal disables the display driver when it is active, blanking the display signaling a recorder inactivation condition. Next, we will explain how it works. Applying power to recorder 10 enables its operation. The supply voltage is 17 to 63Hz with a frequency of 47Hz to 63Hz.
Must be 30 volt AC. The appropriate supply voltage level is indicated by the illumination of the red data display and other indicators. All indicators light up and the display reads “AAAA”.
On the other hand, initial diagnostics and warm-up routines are being performed. Successful completion of warm-up is indicated by a fault display (supply or return air temperature) appearing in the data display.
Confirmed by the current value of The condition indicator distinguishes whether a condition that causes the indicator to emit light is absent. If a fault is detected during diagnosis, "bbbb" will be displayed on the data display and recorder operation will be inhibited. The fault temperature will be indicated on the data display when the warm-up routine is completed. Fault selection is one of three modes, depending on the recorder configuration: Mode Description Return Fault Return air temperature is displayed at power-up. Supply is displayed by operating the Supply/Return key.
When the supply temperature is displayed, the supply air temperature indicator will illuminate. Supply Failure Supply air temperature is displayed at power-up. When the supply/return key is pressed, return is displayed. The supply indicator is always lit. Supply/Return Alternative Each time the Supply/Return key is pressed, the supply air temperature display is alternated with return air. The final selected display is shown at power up. The supply air indicator is illuminated when the supply air temperature is displayed. Selection of other displays is controlled by three other display control keys. Each key causes the selected parameter to be displayed while it is held down. When all keys are released, the display returns to the fault display. Other display control keys are as follows. : Display Key Description Lamp Test Turn on all displays and indicators. Setpoint Display controller setpoint temperature (display controller active probe temperature when external probe test switch is operated). Elapsed time Display time from the start of transportation in hours. The units of temperature are indicated according to the fault unit selection made when power was first applied. Temperature units can be changed by pressing the °C/〓 key. Each time the °C/〓 key is pressed, the unit changes and the selected unit is displayed at the rightmost position of the data display. The beginning of a transportation record is indicated by storing an event in recorder memory. Only one transport start can be recorded. This is done by the following sequence of steps: 1 Press the Elapsed Time key to monitor the elapsed time. 2 Press the transport start key while holding the elapsed time key. 3. Monitor that the elapsed time is reset to 0. 4 Release both keys. At the start of a transport, the operator instructs a new transport by manipulating the "Start Transport" keypad 13 while holding the "Hours Since Last Transport Start (hr)" keypad 15. This is “next time”
The start of a new record is indicated in RAM 124 by causing the pointer to be copied into the "start" pointer and by resetting the store count to zero. Additional elapsed time maintained in clock 130 is also reset to zero. This causes new records to follow old records in memory, preserving old data for as long as possible. A data logger or recorder 10 records the specified parameters once every 30 minutes whenever power is applied to the refrigeration system. The timing is
It is generated internally by clock 140 for use in reporting temperature measurements and the chronology of event occurrences. The recorded data is retained and the timing continues during the event of loss of power to the refrigeration unit. Although no data is captured or recorded during a power outage, the time of last data recording, LTIME, is used to reconstruct the duration of the power outage.
Stored in RAM. The acquired data is stored in a manner that allows for chronological playback. The temperatures and events to be recorded are: (1) The temperature of the air discharged from the refrigeration unit after passing through the coil of evaporator 70 and
Supply air temperature detected by thermistor 74 in 1. (2) The temperature of the air returned to the refrigeration unit from the conditioned air space prior to entering the coil of evaporator 70, as detected by thermistor 75 in conductor 72. (3) Defrost occurrence, which is the state of the defrost signal from the refrigeration unit temperature control device 68. (4) A power outage event, which is an event indicated by the removal and reapplication of AC or DC input control power, and upon power restoration, the duration of the outage calculated from the current clock value, CTIME, and counted in 30 minute intervals. last remembered time,
LTIME. (5) The controller set point temperature, which is the selected operating temperature obtained from the temperature selection potentiometer of the refrigeration unit. The supply and return air sensors, thermistors 74 and 75, are separate and independent from the sensors used for box temperature control. Each of thermistors 74 and 75 is sampled at least once every 5 seconds, averaged over a time interval, such as 30 minutes, and recorded in RAM 124 at the end of that time interval. The set point temperature is recorded in the first data record after the start of "transport start" and thereafter only when it changes by more than 0.5°C during transport. 62 without overwriting the data.
Stored in 6K RAM 124 providing worst case storage for data over 60 days
Recording of up to 60 set point changes and up to 60 power interruptions of duration greater than one recording period is possible. RAM 124 operates as a circular buffer using two pointers. One pointer points to the location of the first record (START), and the other pointer points to the last record recorded in memory (NEXT).
Indicates the location of A circular buffer can be depicted as an endless memory loop. Data is stored in RAM 124 from the lowest RAM address selected by 116 and 118;
to the highest RAM address selected by
Followed by a return to the lowest memory location. Segments of data memory are saved to store pointers and other control parameters. Erasing all memory at the same time is not allowed. As data is written to memory and the address pointer (NEXT) is advanced, it is compared to the first (START) pointer to determine whether the memory location has been used once.
When NEXT is incremented and used as a pointer to the next available memory location, it is used if and only if all memory locations are filled.
Equal to START. After 60 days have elapsed after the start of transportation, the extended transportation indicator 23 will indicate flashing.
Start on and off. When the pointers are equal, the extended transport indicator 23 is made continuous and the extended transport flag is set. An extended transport flag is set to aid in correctly identifying data for printout and is only reset upon activation of transport initiation. Battery 93 is connected to power supply 94 and is suitable for retaining data in RAM 124 for one year over the operating temperature range. The power supply 94 includes a circuit for detecting battery voltage,
When the recorder 10 is supplied with voltage from the outside, the replacement battery indicator 24 is energized in response. The temperature values obtained from the supply and return air thermistors 74 and 75 are used to determine whether an abnormal sensor condition exists, such as an open or short circuit.
The limits are compared to, for example, -38°C to +38°C. If a temperature exceeding the limit is detected, check sensor indicator 22 is energized and remains energized as long as external power to recorder 10 is present or until a valid temperature is detected. stay. For set points of -10 DEG C. and above, the recorder 10 will operate to shut off the refrigeration unit if the supply air temperature drops to 3 DEG C. below the set point for 20 minutes. The supply air temperature is below the set point for 20 minutes under these conditions.
If the temperature continues to remain below 0.degree. C., relay driver 160 is energized, opening the normally closed contacts of relay 162, interrupting power to the refrigeration control unit, and signaling the condition with a remote indicator light. . When a shutdown occurs, the low temperature indicator 21 is activated as a warning to the operator, and once initiated, the low temperature shutdown is latched and can only be reset by removing external power to the recorder.
Relay contacts may alternatively be used for remote signals. Display 19 normally displays the return air temperature at power-up and at all times thereafter unless one of the momentary functions is selected. Operation of the supply/return key 16 causes the display 19 to indicate the supply air temperature and also energizes the supply air display indicator 25 as long as the key 16 is energized.
The release key 16 turns off the indicator 25 and allows the display 19 to return to the air temperature indication. Optionally, the supply and return air temperature indicators may be replaced. This is supply air temperature indicator 2
5 is allowed to become a fault temperature display. The supply/return key 16 is also operable in a toggle mode, with each actuation of the key 16 toggling between maintaining the supply or return air temperature. The fault display remains set to the last selected mode through power interruption and restoration. Supply air indicator 25 is energized whenever the supply air temperature is indicated on display 19. The °C/〓 key 18 allows selection of the unit in which the temperature is displayed on the display 19. key 18
operates in toggle mode on each key press.
That is, the selected mode remains set until the next operation of key 18. When you press the “Time since last transport start (hr)” key 15,
The current value of the recording interval counter is divided by 2 and displayed on the display 19 as long as the key 15 is held. A display value of zero represents a reset condition. When the lamp test key 14 is depressed, all lamps 21-25 are energized as long as it is held. This allows visual confirmation of correct operation of the lamp. The display 19 indicates “-88.8°8” and the indicator lamps 21-2
5 is lit. Release key 14 is display 1
9 and indicator lamps 21-25 to return to their permanent mode. The active temperature sensor value of the temperature controller is displayed by operating an external momentary toggle switch, which switches the setpoint temperature signal from the controller to the active probe temperature signal from the controller and sends it to the recorder. (The active probe temperature will not be recorded as a new setpoint because you are directing the test condition to the recorder by entering and opening a set of normally closed contacts) and when you press the setpoint temperature key 17, this value will be displayed. Ru. During this test mode, recorder 10
Since the set point signal to 2 is being ignored, both controller sensors can be checked by adjusting the set point potentiometer up and down -10 degrees Celsius.
Release key 17 returns display 19 to its failure mode. Recorder 10 forms a single parallel 8-bit bidirectional channel for communicating with interrogator/printer 26 or tape recorder 27. A strobe signal is generated by the "write" signal when an output channel is addressed and data is provided to the printer I/O connector, and an external device such as an interrogator/printer 26 determines the timing of data transfer to the tape recorder 27. control. Input channel is read and CPU92
A confirmation signal is issued to the external device. The data transfer is a unique 5
It is initiated by interrogator/printer 26 or tape recorder 27 placing a bit code on the input line of I/O connector 150 and indicating a data ready signal. Upon recognition of a successful data transfer request, the recorder's display indicates data transfer activity. Data is then transferred from the recorder to the interrogator/printer 26 in a fixed recording length followed by a checksum. If interrogator/printer 26 transmits a negative confirmation, the previous recording is retransmitted. A positive confirmation causes the next block to be transferred until the record transfer is complete. The number of allowable retransmission attempts is limited by interrogator/printer 26. The affirmative or negative confirmation character is the interrogator/
The results of the checksum calculations and comparisons performed on the received data by printer 26 are sent to recorder 10 . A positive confirmation allows the recorder to transmit the next successive block of data or to terminate output if the data transfer is complete. A negative confirmation causes the previous block to be transmitted. The interrogator/printer thereby controls the number of attempts to transmit a block of data. If you fail to obtain confirmation, a 1-byte data transfer is completed, or a “printer giveaway”
If the signal is sent for more than 250 msec, the interrogator service will be terminated and the recorder/interrogator communication will need to be restarted. Interrogator/printer 26 receives data at its maximum data transfer rate and stores the data in internal buffer memory where it is available for analysis and printing. Data received from recorder 10 is decoded into temperature and condition information and separated into separate stores for each recording interval. The format of the data output to the printing device is determined so as to minimize the capacity of the working memory. Interrogator/printer 26 communicates with the operator via keyboard 52 (input) and printer 56 (output). The conversation adapts the interrogator and provides the communication with the operator necessary to retrieve data from the recorder or printed report. In order to transfer the data to the tape recorder 27,
Recorder 10 is commanded through keyboard 100 or from a tape recorder to transfer data to tape recorder 27 . Since the data transfer of information from recorder 10 is a read of information stored in RAM 124, the information remains in RAM 124 until overwritten. In summary, the recorder 10 records the air supplied to the refrigerated container and the air returned from the refrigerated container.

【table】

【table】

Table of Contents While the preferred embodiment of the invention has been illustrated and described, various modifications may be made by those skilled in the art. For example, an interrogator/printer may be located at a remote location and connected to the recorder through appropriate wires and a modem. Also, an interrogator/printer can be combined with a recorder to record and recall within one unit. Accordingly, the scope of the invention should be limited only by the scope of the claims that follow.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the recorder and data transfer structure. FIG. 2 is a functional block diagram of the recorder. FIG. 3 is a block diagram of the interrogator/printer. 4A, 4B and 4C are block diagrams of the recorder. FIG. 5 is a schematic diagram of the power supply section of the recorder. FIG. 6 is a schematic diagram of the reset circuit. FIG. 7 is a diagram showing a modified panel. 10... Data recorder, 11... Refrigerated container, 12... Control panel, 13-18... Membrane key, 19... Display, 20... Indicator panel, 21-25... Indicator lamp (indicator) , 26...Interrogator/printer, 2
7...tape recorder, 28...calculator, 29...
...Offline teleprinter, 32...Signal interface, 34...Control logic circuit, 36...Memory, 38...Interrogator/printer tape recorder interface, 40...Display interface, 42... ...power supply section,
43...battery pack, 44...charger, 45...
I/O connector, 46... Control circuit, 47...
I/O buffer, 48...Single/chip
CPU, 50...keyboard controller, 51...scan decoding, 52...keyboard, 55...printer driving electronic circuit, 60...program memory, 62...data memory, 64...address latch, 65 ...Address decoding, 66
... Audible signal, 68 ... Temperature control device, 69 ...
Interface and power connector, 70... Evaporator, 74, 75... Thermistor, 76... Excitation circuit, 78, 79... Multiplexer, 80... Clamp circuit, 82... Division circuit,
84...Analog-digital converter, 86...
Voltage reference, 88...Division circuit, 90...Buffer, 92...CPU timer RAM, 100...Keyboard, 16...Address latch, 110...
Address decode, 116...Low RAM address, 118...High RAM address, 124...
CMOS RAM, 130...Clock, 134...
...Display control section, 136...Current control section,
138...digit driver, 140...
LED display, 146...Printer data buffer, 150...Printer I/O connector, 160...Relay driver, 162...Relay.

Claims (1)

[Scope of Claims] 1. In a recording device for recording a plurality of conditions in a refrigeration system for later recall, means for accepting a plurality of inputs representing refrigeration system conditions, comprising: a means for accepting information and providing a first analog signal indicative of supply air temperature; b means for accepting information and providing a second analog signal indicative of return air temperature; c means for accepting information and providing a third analog signal indicative of a thawing condition; d means for accepting information and providing a fourth analog signal indicative of a temperature set point; e multiplexing means for individually selecting each one of said four analog signals and providing said selected signal as a first output signal; f digitizing said first output signal and providing said first output signal; analog-to-digital converter means for providing one output signal as a second output signal; and logic for processing and periodically storing the second output signal in time order; Memory means comprising: a random access memory means for storing data and recalling stored data; b random access memory for operating the random access memory as a circular buffer; a random access memory addressing means for providing address information to the random access memory addressing means; c. an address address having a plurality of output signals for providing instructions to the random access memory means and said random access memory addressing means; decoding means; d. said multiplexing means for individually selecting each one of said four analog signals; d. said analog-to-digital converter for accepting said second output signal; d. said address. said address decoding means for producing said output signal to said decoding means; d. a central processing unit and program memory means connected to said random access memory means for completing storage of data; logic and memory means for accepting an information query and transferring said data stored in said random access memory means in response to said information query; and for transmitting said data stored in said random access memory means under the control of said central processing unit and program memory means in response to said information query; and means including input/output connector means connected to said logic and memory means.