JP3350904B2 - Data transfer method between programmable controller and motion controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transmitting and receiving data between a PLC and a MC in a system in which a programmable controller (hereinafter abbreviated as PLC) and a motion controller (hereinafter abbreviated as MC) are connected by a two-port RAM.

[0002]

2. Description of the Related Art Conventionally, a method of exchanging data between a PLC and an MC has been performed using a hardware configuration shown in FIG. In FIG. 2, the PLC 201 and the MC 202
PLC 201 coupled by port RAM 208
Are the input / output device 206, the CPU 203, the ROM 204,
It comprises a RAM 205 in which a ladder program and input / output data are stored, and a communication interface device 207. The MC 202 has a 2-port RAM 2
08, input / output device 212, CPU 209, ROM 21
0, RAM 211. Next, the operation of the present system will be described with reference to FIG. Input data input from the input / output device 206 of the PLC 201 is taken into the RAM 205. A ladder program is stored in the RAM 205 in advance.
According to the FF information, the CPU 203 activates the control program in the ROM 204 and decodes the ladder program. Of the decrypted data, output data outside the system is
Output signal 21 out of the system via input / output device 206
Conveyed as 4. On the other hand, MC of the decrypted data
The data required to control the
To the MC. Here, the method of transmitting and receiving data between the PLC and the MC via the two-port RAM includes a semaphore method using an interrupt or the like or an asynchronous method in which arbitration is performed by hardware and completely asynchronous. . By the way, since the MC operates by feedback control unlike the above-described scan operation, in order to decode the MC program, a high-speed and fixed period of time is required for input / output data exchange between the MC and the outside of the system. Is done. To fulfill this request,
The MC 202 has an MC-dedicated input / output device 212 through which input / output data is exchanged with the outside of the system.

[0003]

However, in the prior art, when one of the input / output devices in both the PLC and the MC is deleted to simplify the system, there are the following problems.
That is, when an input / output device is provided only on the MC side, MC
The number of data input / output points required for data transmission is extremely small compared to that required for the PLC.
In order to perform the input / output processing of the data for C, there is a problem that a large-scale modification of hardware is required. When an input / output device is provided only on the PLC side and input / output data is exchanged between the outside of the system and the MC using the input / output device as an interface, the input / output data dedicated to the MC is stored in the RAM 205 once. Are transmitted and received via a 2-port RAM through a ladder program decoding process,
It has been impossible to constantly transmit and receive input / output data between the outside of the system and the MC in a high-speed and constant period of time. In view of the above, the present invention solves the above-described problem when the PLC and MC input / output devices are integrated into one, and provides a PLC and a MC that can exchange input / output data dedicated to the MC at high speed in a fixed period of time.
An object of the present invention is to provide a method of exchanging data between Cs.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a system in which a programmable controller having an input / output device, a RAM, and a motion controller are connected by a two-port RAM to transfer data between the programmable controller and the motion controller. In the transmission / reception method, the programmable controller transmits and receives data between the RAM of the programmable controller and the motion controller via a partial area of the two-port RAM based on a program decoding result of the scan cycle. An interrupt program of the programmable controller is operated for each clock signal having a constant cycle independent of the cycle, and the input / output device is operated.
Specific input / output data among the input / output data
With the input / output device via the other area of the 2-port RAM
Data is directly transmitted and received between the motion controllers at the predetermined short period .

[0005]

According to the above-mentioned means, it is possible to exchange MC-dedicated input / output data between the PLC input / output device and the MC at a high speed and at a constant cycle irrespective of the PLC scan cycle. The circuit is integrated and the system is simplified.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of a hardware configuration for implementing a signal transfer method of the present invention.
101 and MC 102 are connected by a two-port RAM 108. Here, the PLC 101 is a CPU 10
3, a ROM 104, a RAM 105, a communication interface circuit 107, and an input / output device 106. Among the input / output circuits included in the input / output device 106, a signal input / output circuit for directly transmitting and receiving input / output data between the outside of the system and the MC is particularly called a direct input / output circuit, and the input / output circuit is transmitted / received via the direct input / output circuit. The signal performed is called direct input / output data. The MC 102 is a CPU 10
9, ROM110, RAM111 and 2-port RAM1
08, and the 2-port RAM 108 has a PLC and M
Transfer of C data is performed. FIG. 3 is a flowchart showing the operation of the scanning process of the PLC among the control programs stored in the ROM 104. Figure 4 shows the ROM
4 is a flowchart showing direct I / O processing of a PLC among the control programs included in the control program 104; FIG.
Is the clock generated by the PLC and the direct I / O processing.
And management is a timing diagram illustrating the access side of the two-port RAM. The 2-port RAM 108 is a switch memory that accesses the PLC when this signal is “H” and accesses the MC when this signal is “L”. Hereinafter, the operation of the present invention will be described. Of the input signal 112 and the output signal 113 outside the system in FIG.
Data is exchanged between the input / output device of the LC and the RAM 105 of the PLC. Input / output data outside the system is exchanged with the RAM 105 via the input / output device 106,
Thereafter, in a ladder decoding process 301, the ladder program stored in the RAM 105 is read by the CPU 103.
Therefore it decrypts the fourth control program, decrypted data is again placed in RAM 105. And personal computer
Command processing 302 (PC 103 of personal computer and PLC)
After performing the communication process between the
Then, the input data is again taken into the RAM 105 from outside the system via the input / output device, and the output data is output from the RAM 105 via the input / output device 106 to the outside of the system as a signal. Next, in the MC unit service 304, data dedicated to the MC other than the direct input / output data (of the data required by the MC, data transmitted and received after performing the PLC program decoding process)
The data is transferred to a part of the 2-port RAM. The exchange of data between the PLC and the MC in the partial area via the 2-port RAM is asynchronous, and the PLC exchanges data with the 2-port RAM by the MC unit service in the flowchart of FIG. The MC side exchanges data with the 2-port RAM at the falling edge of the clock shown in FIG. Thereafter, the program returns to the ladder circuit decoding process again, and the above operation is repeated. By the way, the input / output signal for controlling the MC operates as follows. M
The C-dedicated input data is once taken into the direct input / output circuit in the input / output device 106 and interrupts the scan process executed by the CPU 103 of the PLC at the rising of the clock signal in FIG. Direct input / output processing is executed. As a result, input data dedicated to the MC is transferred from the input / output device 106 to the 2-port RAM 108.
Passed directly to At this time, the output data is directly passed from the two-port RAM 108 to the input / output device 106 and is output as an output signal to the outside of the system. After executing all of the direct input / output processing, the scan processing program is executed again from the point where the interrupt is input. When the clock signal falls, the two-port RAM and the MC exchange data. The transmission and reception of data between the PLC and the MC are completely synchronized because the two-port RAM 108 is a switch memory, and the PLC and the MC are smoothly transmitted without any delay such as wait due to arbitration. Further, the processing time of the PLC and MC shown in FIG.
It is set from the responsiveness of input / output data that requires the high speed of C. As described above, since the input / output data dedicated to the MC is processed within the processing time of each time, the input / output data used by the MC for the calculation or the like does not have a time lag due to scanning. As described above, as an integrated system of PC and MC, input / output data is exchanged with the outside of the system by only one input / output device, and input / output data of MC requiring high speed can be processed.

[0007]

As described above, according to the present invention, P
Since the processing of input / output data can be realized at one place in the PLC when configuring a system in which the LC and the MC are combined, the system configuration is simplified, and the total system size and cost can be reduced. Also, without being restricted by the PLC scan cycle, the MC
It is now possible to constantly transfer input / output data to and from the device at high speed and for a fixed period of time.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically illustrating a hardware configuration according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a hardware configuration of a conventional example.

FIG. 3 is a flowchart illustrating a PLC scanning process.

FIG. 4 is a flowchart showing direct input / output processing according to the present invention.

FIG. 5 shows a clock signal , direct I / O according to the invention .
The figure which shows the relationship of a process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Programmable controller 102 Motion controller 103 Programmable controller CPU 106 I / O device 107 Communication interface device 108 2-port RAM 109 Motion controller CPU 112 Input signal 113 Output signal 201 Programmable controller 202 Motion controller 212 MC dedicated input / output device 213, 215 Input Signal 214,216 Output signal

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-27405 (JP, A) JP-A-2-173804 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G05B 19/04-19/05

Claims (1)

(57) [Claims] 1. A method for exchanging data between a programmable controller and a motion controller in a system in which a programmable controller having an input / output device, a RAM, and a motion controller are connected by a two-port RAM, wherein the programmable controller has a program decoding result of a scan cycle. based on the performed transfers data between RAM and the motion controller of the programmable controller through a partial area of the two-port RAM, while the programmable controller for each clock signal having a constant period independent of the said scan cycle of the interrupt program is operated, and out by the input-output device
Specific input / output data of the input data
M and the motion input / output device through the other area of M.
A method of transmitting and receiving data between a programmable controller and a motion controller , wherein data is directly transmitted and received between the controllers at the above-mentioned fixed period .