JPH02150902A - Data transmission system - Google Patents

Abstract

PURPOSE:To shorten the time required for transmission of a large quantity of data by setting the proper lag times against the rise and fall time points of a strobe signal after switching this signal in a cycle T and meanwhile reading the data. CONSTITUTION:In case a host computer 2 functions as a programmable controller, a strobe signal SR is switched between H and L levels in the same period as the changing period T of the 2-bit data forming the state information MD. The head data shows the address of a state information RAM 41. While a picture display controller 1 uses the rise and the fall of the signal SR as triggers to apply a prescribed time lag and produces a read control signal RS when a time Td elapses to read the data. In this case, the lag time Td is set shorter than the period T with the H-L switching time point of the signal SR defined as a start point and also setlonger than the least time time during which the 2-bit data forming the information MD is set at the stable value, i.e., the rise time of an input circuit 21 and the fall time of an output circuit 23 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a data transmission system from a main information processing circuit such as a host computer to a terminal information processing circuit equipped with a display or the like.

(Prior Art) Conventionally, an image display device is connected online to a host computer, and the operating status of a plant consisting of tanks, piping, valves, etc., and the process information of a machine shop are displayed on the screen of the image display device. It has been proposed to display and monitor the progress status etc. (For example, Japanese Patent Publication No. 52-6130
reference).

In this type of image display device, monitoring data from instrumentation systems such as tank level meters and limit switches that detect opening and closing of valves is first sent to a host computer. The host computer processes the monitoring data according to a preset procedure, creates a control command for changing the image, and sends it to the image display device.

As a result, the image drawn on the image display device is changed in accordance with the change in the monitoring data.

(Problem to be Solved) When a so-called programmable controller is used as a host computer, the communication method between the programmable controller and the image display device is as follows. ), input processing that takes in monitoring data from the instrumentation system.
P, and a predetermined program processing P for the monitoring data.
P and output processing oP for outputting the processing results are cyclically repeated at a constant period T.

In the conventional transmission/reception system, the programmable controller maintains the output data MD by the output processing OP for a period twice the period T (2T) as shown in FIG. The 9-point programmable controller, which repeats in cycles, generates a strobe signal SR for synchronizing data reception on the image display device side along with the output data.
and a star signal ST for specifying the start point of a series of data (DI, D2, . . . ). Here, the reason why the output data MD is maintained for a period of 2T is because the image display device takes in the data MD at the falling edge of the strobe signal SR, and the falling and rising edges of the strobe signal are controlled by the program processor F! ! This is because it is formed by the execution of PP.

On the other hand, the image display device performs a reception operation in synchronization with the received strobe signal and start signal, determines that the output state of the data MD is stable at the falling edge of the strobe signal, and outputs the data at the falling edge of the strobe signal. Incorporate MD.

Therefore, in the conventional communication system, the cycle of data communication is 2T, and there is a problem in that it takes time to transmit a large amount of data.

An object of the present invention is to switch the strobe signal at the cycle T of the program processing, set an appropriate delay time from the rising and falling points of the strobe signal, and read data when the delay time has elapsed. In the data transmission system according to the present invention, the main information processing circuit is configured to perform data processing. Data MD and strobe signal SR are changed in the same period as period T.

Further, a timer means is set in the terminal information processing circuit to measure a predetermined delay time TtJ from the falling and rising points of the received strobe signal. The delay time Td is the time required for the changed data to become stable Tll1i
The timer means is set to a length longer than n and shorter than the period T, and is activated from the rise and fall times of the strobe signal, and reads data at the time of delay time TJ.

(Operations and Effects) According to the transmission system of the present invention, data and strobe signals can be updated at the same cycle as the data processing cycle T of the main information processing circuit, thereby allowing rapid communication. However, since the optimum delay time T' can be set in consideration of variations in the rise time Ton or fall time Toff of the input/output circuit, reliable reception processing is guaranteed.

(Examples) Examples are provided to explain the present invention, and should not be construed as limiting the invention described in the claims or reducing its scope.

Hereinafter, a configuration example of an image display control device for implementing the present invention will be described in detail with reference to the drawings. Although the image display control device also has the functions of a conventional general graphic display device, illustrations and explanations of these well-known configurations will be omitted.

The image display control device (1) is connected online to the host computer (2) as shown in Fig. 2, and includes a communication controller (13) and a keyboard (12) for receiving data from the host computer (2). I10 controller (14) for receiving input signals from CP
U (15), ROM (4) in which system programs (Figs. 9 to 11) described below are registered, various R described below.
A M (41) (42) (43) (44), a register (3) for controlling the data read timing by the communication controller (13), and a display (
14) is provided with a graphics controller (5) for controlling the drawing operation.

The video RAM (44) is used to develop the data in the graphic RAM (43) into an image on the display screen when the graphic controller (5) controls the drawing operation of the display (11).

On the other hand, the host computer (2) is a programmable controller, and includes an input circuit (21) for receiving monitoring data from the instrumentation system and storing the received monitoring data in memory according to a predetermined procedure. Processing circuit for (
22), and an output circuit (23) for reading data from the processing circuit (22) and sending it to the image display control device (1) together with a strobe signal SR and a start signal ST, which will be described later.
It consists of

FIG. 3 shows the correspondence between the address space of the status information storage memory (24) provided in the host computer and the address space of the status information RAM (41) of the image display control device. As shown in the figure, the 0th
An 8-bit long storage section consisting of bits to seventh bits is provided at necessary addresses (0th address to Nth address).

The monitoring data supplied to the host computer (2) is processed by a procedure preset in the processing circuit (22).
After being converted into binary data of 0"1" (status information MD), from the 0th bit of the memory (24)/\0th address,
The first bit of the 0th address, . . . , the 0th bit of the 1st address, . . . are stored in order.

When one cycle of monitoring data from the instrumentation system is stored in the memory (24) of the processing circuit, the data in the memory (24) is transferred to the image display control device (1) by the operation of the output circuit (23). The status information RAM (41)'\ is transmitted and stored via the communication controller (13). On this occasion,
The data stored in the memory (24) of the host computer is
The read and write operations are controlled so that the data is moved to the storage location indicated by the same bit and address of the state information RAM (41) of the image display control device, and the contents of both memories are the same.

FIG. 4 shows the configuration of the display change processing Hw stored in the event RAM (42). Hereinafter, the structure of the display change processing word W when changing the display color of the bulb will be specifically explained based on FIGS. 5 to 7.

The screen in FIG. 5 is composed of three display blocks showing a tank (7), a pipe (71), and a valve (2).

The tank (7) and piping (71) are created as a fixed image on the display (11) as shown in Fig. 6, and the graphic data is stored in the graphic RAM (43) with a file number Fl (for example, No. 1). ing.

Also, as shown in the seventh factor, the valve (2) is created as a separate image block that can be called relative to the fixed image, and the file number F2 (for example, number 700) is stored in the graphic RAM (43). is registered with.

When registering the display change processing word W in the event RAM (42) of FIG. 4, the apparatus is set to the drawing mode, and the registration procedure shown in FIG. 9 is performed by operating the keyboard (12).

By keying the file number Fl (number 1 in this case) of the fixed image mentioned above, the file number is stored at address 0 of the event RAM (42) shown in FIG.

Next, state information (for example, "
Address A1 and bit address Bl (for example, A1-〇, B1=
O), these data can be used as event RA
They are stored at the first and second addresses of M (42), respectively.

Further, the address AI of the state information RAM (41),
The bit of the state information stored in bit address Bl is ON (
0N10FF data S (for example, “
1°°). The data is event RAM (42
) is stored at the third address.

Next, the type of image block (event) whose display should be changed,
In other words, data that distinguishes whether the display is a mark such as a valve, a library with a more complex structure than a mark, a time display, etc. (For example, when displaying a mark, the ).

The data is stored at address 4 of the event RAM (42).

Ru.

As shown in Fig. 5, a “valve °
To display the event name TN ', enter the display start position of the event name on the screen, and then press the key "Valve". These data are stored in the 5th and 6th addresses of the event RAM (42). Stored in address.

Next, state information RAM (41
) in address A2 and bit address B2 (for example, A2-0
, B2=1), these data are stored at the seventh and eighth addresses of the event RAM (42), respectively.

Furthermore, the registration file number F2 of the valve image 1 block
By keying the file number (here, number 700), the file number is stored at address 9 of the event RAM (42).

After that, when the status information of address A2 and bit number tlB2 is ON (“1”) and OI? Key in the ゎzu ON10 FF color information ZD. For example, when ON, operate the red designated key, and when OFF, operate the green designated key. The ON10 FF information ZD is the event R.
It is stored at address 10 of A M (42).

Coordinate data I-(D (X and Y shown in FIG. 5) indicating the display position of the mark (bulb) on the screen is input to Rlk. This coordinate data is the 11th
Stored in address.

By repeating the above procedure for creating the display change processing word W for all the events that should be changed,
Registration of A M (42) is completed.

Incidentally, the above procedure can be easily carried out in an interactive manner between the display (11) and the user's key operations.

Next, regarding the operation in the operation mode in which the image display control device (1) is connected to the host computer (2),
9 to be explained with reference to FIG. 10. When the power is turned on to the apparatus, first it is determined whether or not it is in an online state with the host computer, and if NO, the above-mentioned drawing mode is set. If YES, data communication processing is performed from the host computer (2) to the image display control device (1), and status information RAM (41
) The status information MD is written to 9. Next, the contents of a large number of display change processing words W stored in the event RAM (42) are sequentially read out and the following procedure is executed.

First, based on the screen call address A1 and screen call bit B1 included in the read display change processing word W, read the value of the state information MD stored at address (At, Bl) of the state information RAM (41). , the read value and the screen call ON included in the display change processing word, -
' Compare with the value of OF data S. If there is a mismatch, it is determined that the host computer (2) has not instructed to change the display, and the process returns to the data communication process.

When the state information MD and the 0N10FF data S match, the file number F included in the display change processing word W
1, a fixed image is called from the graphic RAM (43).

Next, the mode is branched according to the type of event included in the display change processing word W, and processing is advanced for each mode. For example, in the case of displaying a mark (valve), the event included in the display change processing word Based on the name start position and the event name TN,
The event name TN (
'Draw valve °).

Thereafter, based on the event display call address A2 and the event display call bit B2 included in the display change processing word W, the state information data MD is read out from address (A2.B2) of the state information RAM (41). Data M
It is determined whether the value of D is "'ON" or 'OFF'.

If the above judgment result is "ONoo", the graphic data of the image block (bulb) registered in the graphic RAM (43) is read out based on the registered file number F2 included in the display change processing word W, and An image block (bulb) is displayed at the screen position specified by the coordinate data HD included in the display change processing word W in the color (red) when the ON10FF color information is "'ON". If the judgment result is "OF", the graphic data of the image block (bulb) registered in the graphic RAM (43) is read out based on the registered file number F2 included in the display change processing word W, and further The 0N10FF color information is “OFF” at the screen position specified by the coordinate data HD included in the display change process 3”W.
” Displays the image block (bulb) in the color (green).

Thereafter, the process returns to the data communication process and continues the display change based on the next display change process 1W.

Through the above procedure, the screen of the display (11) changes every moment according to the data sent from the host computer (2).

In the image display control device (1), a program is provided to the host computer (2) that converts monitoring data from the instrumentation system into status information and stores it in the memory (24) shown in FIG. However, most of the programs store the monitoring data directly in the memory (24) as status information.
Since the process involves moving the file to the specified location I\, it is extremely easy to create a program.

Furthermore, in the image display control device (1), an event base TN is written for each event for which a display change is to be made for the event RAM (42) in FIG. When it is desired to modify the registration of (42), it is possible to cross-search event RAM (42) using the event group as a keyword. This result is, for example, the 8th
The data will be edited and output as a diagram as shown in the figure. Therefore, the user can easily refer to this diagram and
M (42) can be rewritten, which is convenient.

Next, a transmission/reception method between the image display control device (1) and the host computer (2) shown in FIG. 2 will be explained.

When the host computer (2) is a well-known programmable controller, the input circuit (21), processing circuit (22) and output circuit (23) of the host computer (2) are as shown in FIG. 12(a) and FIG. 13(a). As shown in FIG. return.

In the conventional transmission/reception method between an image display device and a programmable controller, the programmable controller
Output data M by output processing OP as shown in FIG. 13(b)
D is maintained for a period twice the period T (2T), and this is repeated at a period of 2T.

In addition to the output data, the programmable controller also generates a strobe signal SR for synchronizing data reception on the image display device side, and a series of data (D+-Dz...
) and outputs a start signal ST for specifying the start point. Here, the reason why the output data MD is maintained for a period of 2T is that the image display device takes in the data MD at the falling edge of the strobe signal SR, and the falling and rising edges of the strobe signal are determined by the execution of the program processing PP. On the other hand, the image display device performs a receiving operation in synchronization with the received strobe signal and start signal, and determines that the output state of the data MD is stable at the falling edge of the strobe signal. , data MD is taken in at the falling point.

Therefore, in the conventional communication method, the period of data communication is 2T.
Therefore, there was a problem in that it took a long time to transmit a large amount of data.

Therefore, as shown in FIG. 12, a transmission/reception method capable of performing data communication at a period T was developed and adopted in this embodiment.

That is, in this embodiment, as shown in FIG.
・D, ・D,) “H” and “
In this embodiment, the first data D1 is the state information RAM (4
1) shows the address.

On the other hand, in the image display control device (1), a predetermined time delay is applied using the fall and rise of the strobe signal SR as a trigger, and when the delay time Td has elapsed, the first
A read control signal R8 is generated as shown in FIG. 3(d), and data is read.

The delay time Td is 'II'"L of the strobe signal SR.
The minimum time Te1i that is shorter than the period T and until the data shown in FIG.
n, that is, is set longer than the rise time Ton of the input circuit (21) and the fall time Toff of the output circuit (23).

The delay time Td is set as a timer in the read timing register (3) shown in FIG.

The specific procedure of the data reception process will be described below with reference to FIG.

First, it is determined whether or not the image display control device is online, and if the answer is NO, a message prompting the user to set the delay time Td is displayed on the screen. After key-in at Td, the data is set in the read timing register, and the process returns to determining whether or not the system is online.

In the case of online, the start signal ST is from "L" to "
I]°° and when a change occurs in the strobe signal SR, a timer set in the read timing register is activated.

Thereafter, when the delay time Td becomes tight, a read control signal shown in FIG. 1(d) is generated to start reading data.

Next, determine whether the start signal is H or not, and select YES.
In this case, data D (address) is read and the write start address of the state information RAM (41)'\ is set, and then the process returns to the procedure for determining the change in the strobe signal. When the start signal is L'°, data D2, Dl,
D, (state information) is read and these are state information RA.
M (41)/\Storage.

Thereafter, it is determined whether or not it is desired to finish storing the state information RAM (41) to all addresses, and if NO, the address of the state information RAM is incremented to continue storing subsequent data. If YES, the status information tlfIRA M (41) and event R shown in FIG.
AM (42) and Graphic RAM (43)
After performing graphic processing based on
\Move.

According to the above transmission/reception method, data can be updated at the same cycle as the program processing cycle T of the programmable controller as shown in Fig. 12, and rapid communication can be performed. Signal rise time To
Since the optimum delay time Td can be set taking into account the variation in n or falling time Toff, reliable reception processing can be achieved (
I'm stunned.

The drawings and the description of the above embodiments are for illustrating the present invention, and do not limit the invention described in the claims.
Nor should it be construed as limiting the scope.

Further, it goes without saying that the configuration of each part of the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the technical scope of the claims.

For example, the timer means for setting the delay time Td may be not only a software timer but also a hardware timer. In this case, Td can be changed by a switch or the like. be.

Further, the address data D1 shown in FIG. 1 can also be used as a start signal, thereby enabling efficient data transmission.

The transmission method of the present invention can be applied not only to parallel transmission but also to serial transmission. Furthermore, it is effective not only for communication aimed at the image display control device (1) as in the present embodiment, but also as an information transmission method aimed at numerical information processing circuits.

[Brief explanation of the drawing]

FIG. 1 is a timing chart explaining the data transmission method of the present invention, FIG. 2 is a block diagram showing the specific configuration of the image display control device and the host computer, and FIG. 3 is the memory and status information RAM in the host computer. 4 is a diagram showing the structure of the display change processing word stored in the event RAM, FIG. 5 is a diagram showing an example of a display screen, and FIG. 6 is a diagram showing the structure of the screen. Figure 7 is a diagram showing the fixed image part, Figure 7 is a diagram showing image blocks whose display should be changed, Figure 8 is a diagram showing the results of a cross search using event names as keywords, Figure 9 is the operation in drawing mode. 10 is a flowchart showing operations in the operation mode, FIG. 11 is a flowchart showing data transmission and reception operations, and FIGS. 12 and 13 show the data transmission method of the present invention and the conventional data transmission method. This is a timing chart for comparison. <1)...Image display control device (2)...Host computer (11)...Display SR...Strobe signal Td...Delay time

Claims (1)

[Claims] [1] A data transmission method from the main information processing circuit to the terminal information processing circuit, in which the main information processing circuit repeats data processing and output processing according to a predetermined procedure at a constant period T, thereby transmitting terminal information. Data MD representing information to be transmitted to the processing circuit, a strobe signal SR serving as a synchronization clock for data transmission, and a start signal ST specifying the start of a data block constituted by the data are simultaneously transmitted to the terminal information processing circuit. In the data transmission method,
The data MD and the strobe signal SR change at the same cycle as the data processing cycle T of the main information processing circuit, and the terminal information processing circuit measures a predetermined delay time Td from the falling and rising points of the received strobe signal. A timer means is set, and the delay time Td is longer than the time Tmin required for the changed data to stabilize, and the period Td is longer than the time Tmin required for the changed data to stabilize.
The data transmission system is characterized in that the timer means is activated from the rise and fall times of the strobe signal, and data is read when the delay time Td times up.