JPH0260332A - Data collector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data collection device, and particularly to a data collection device used as a vehicle operation recorder.

[Conventional technology]

In vehicle operation recorders, etc., EMI (Electronic Ma
Electrical noise may be superimposed due to gnetic InLerrerence (electromagnetic wave interference), and this electrical noise may cause data destruction (for example, even though the sensor has transmitted a digital signal of "1", the electrical gjt
In order to prevent problems such as arriving at the driving recorder as "0" due to the influence of EM+MI routers and those equipped with feedthrough capacitors are known.

To briefly explain this based on FIG. 5, this example is a data collection device as a vehicle operation recorder, and one end of the shielded wire 5 provided outside the communication line 1 is connected to the case 43 of the sensor 4. By grounding the other end through the case 33 of the driving recorder 3, the communication line is shielded to reduce the influence of electrical noise from the outside due to L' and MI.

Furthermore, EMI filters (or feed-through capacitors) 32, 42 are provided between both ends of the communication line 1 and the data receiving circuit 3I and the data output circuit 41, so that electrical noise that has entered the communication line 1 due to EMI is removed from the data. Receiving circuit 3I
It is made so that it is difficult for people to get into it.

[Problem to be solved by the invention]

However, in the case of the data collection device as a vehicle operation recorder as described above, since the vehicle body is made of metal, the operation recorder case 3 fixed to the vehicle body is made of metal.
3 and the sensor case 43 are both grounded to the body, and when the shield wire 5 is connected to these cases, the operation recorder case 33, the shield wire 5, and the sensor case 4 are connected.
This creates a ground loop consisting of 3 and the body.

In addition, an induced current flows in the ground loop due to changes in the interlinked magnetic flux of EMI, and this induced current sometimes causes electrical noise to be superimposed on the communication line.

For this reason, if the driving recorder case and sensor case are both grounded as described above, there is a problem in that it is not possible to directly connect the two cases with a shielded wire to avoid the formation of an asloop. However, if the energy of the electromagnetic waves is large, there is a problem that the coil becomes magnetically saturated or, in the case of a Vt type capacitor, the capacitor breaks, making it impossible to eliminate noise caused by EMI.

Therefore, the present invention enables E
An object of the present invention is to provide a pig collecting device that can reduce the influence of MI.

[First stage of failure to solve the problem] In order to achieve the above object, the data collection device according to the present invention includes a communication line and a harness for detecting external noise provided in 7 rows, and a harness for detecting external noise provided in the communication line and seven lines. A circuit that detects the induced noise voltage, records the received data from the communication line in the memory while the output voltage of the circuit is below the permissible value, and when it exceeds the permissible value, records the latest data before exceeding the permissible value. calculation means for recording the received data in the memory.

[For production]

In the present invention, the calculation means reads the noise voltage induced in the extraneous noise detection harness provided in parallel with the communication line as the output voltage of the noise voltage detection circuit. Then, while this output voltage is below the set value, the data received from the communication line is recorded in the memory, and when the output voltage exceeds the set value, it is determined that it is affected by EMI etc. , the latest data before exceeding the set value is recorded in memory.

Therefore, the calculation means collects data with high reliability by holding data that is less affected by EMI in the memory.

〔Example〕

Embodiments of the data collection device according to the present invention will be described below.

FIG. 1 is a block diagram showing the system configuration of an embodiment in which the data collection device according to the present invention is used as a vehicle operation recorder, where 1 is a communication line and 2 is parallel to the communication line 1. 3, a data receiving circuit 31 connected to the communication line 1, and a data receiving circuit 31 connected to the communication line 1, and a harness 2 connected to the communication line 1,
Noise voltage detection circuit 34 that detects EMI etc. generated on the
4 is a sensor or data transmission source having a data output circuit 41 connected to the communication line 1; Second
The figure is a flowchart of a program executed by the CPU 35, and the operation of the system configuration shown in FIG. 1 will be explained based on this figure.

When this program starts, it first resets the noise flag (step SO in FIG. ), C.P.
U35 checks whether the detected voltage of the noise voltage detection circuit 34 exceeds the set value (dark value) (step S2).
.

Here, one embodiment of the EMr detection circuit 34 will be explained based on FIGS. 3 and 4. FIG. 3 is a block diagram showing the circuit configuration, and 343 is a half-wave A half-wave rectifier circuit for rectification, 342 a set voltage generator, 341 a half-wave rectifier circuit 34 that compares the output voltage of the half-wave rectifier circuit 343 and the output voltage of the set voltage generator 342.
When the output voltage of 3 exceeds the output voltage of the set voltage generator 342, voltage "11" is output, and when it does not exceed the output voltage, voltage "I7" is output.
It is a voltage comparator that outputs Note that the set voltage generated by the set voltage generating section 342 is determined and set in advance through experiments to a voltage that will not cause data destruction even if noise is superimposed on the communication line 1 due to EMI or the like.

FIG. 4 is a waveform diagram of the operation of this noise voltage detection circuit. When an AC voltage [■] as shown in FIG. 4(a) is generated on harness 2 by F and MI, it is half-wave rectified. A circuit 343 rectifies and smoothes 16 waves and outputs the result as shown in FIG. 4(1)). Then, the voltage comparator 341 compares this half-wave rectified output voltage with the set voltage from the set voltage generator 342, and sets the voltage H while it is higher than the set voltage (between time t1 and t2 in FIG. 4(C)). Output to CPU35.

In this way, when the voltage comparator 341 outputs the voltage II in step S2, the CPU 35 holds the received data D, in the register R (step S3), but outputs the voltage II. Output voltage when
The data R held in register R immediately before , became H
,, (remains until updated) (step 34), and sets the noise flag in step S.
5), writing process to memo IJ 36 (same step S6)
Proceed to.

Therefore, the CPU 35 uses the latest data before the occurrence of the abnormality instead of the data at the time of abnormality due to EMI or the like.

If the noise flag is set in step S7, the presence of extraneous noise is recorded in the memory 36 (step S8), so that it can be later identified which data has passed through step S4.

Although the above embodiment has been explained using a driving recorder, it goes without saying that the data collection device according to the present invention can be applied to a wide range of control systems such as general engines and tJf vehicles.

〔Effect of the invention〕

As described in -1- above, the data collection device according to the present invention retains the data received when the voltage generated in the external 941 sound detection half strike provided in the V line of the communication line is below the set value, and also retains the data received at the set value. When the set value is exceeded, the data received just before the set value is exceeded is retained, so the data that is retained is less affected by I-) Ml, etc., so the reliability of the collected data is said to be high. effect can be obtained.

In addition, it is possible to reduce the effects of EMI that occurs extremely rarely when a vehicle equipped with a high-power radio passes by a vehicle equipped with the device of the present invention, and it can also be used to control the temperature of cargo. This is particularly effective for signals with small data changes, such as those from recorders.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the system configuration of an embodiment of the data collection device according to the present invention, FIG. 2 is a flowchart of a program executed by the calculation means used in the present invention, and FIG. FIG. 4 is a block circuit diagram showing an embodiment of the EMI detection circuit used in the invention. FIG. 4 is an operational waveform diagram for noise voltage detection. FIG. 5 is a block diagram showing the system configuration of a conventional data acquisition device. In FIG. 1, 1 is a communication line, 2 is a harness for detecting external noise, 31 is a data receiving circuit, 34 is a noise voltage detection circuit, 35 is a CPU, and 41 is a data output circuit. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A harness for detecting external noise installed in parallel with a communication line, a circuit for detecting noise voltage induced in the harness by the external noise, and a circuit for detecting noise voltage from the communication line while the output voltage of the circuit is below a permissible value. 1. A data collection device comprising: arithmetic means for recording received data in a memory and, when exceeding the tolerance value, recording the latest received data before exceeding the tolerance value in the memory.