JPH0744550B2 - Loop / multi-drop module device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is particularly intended for application to distributed instrumentation systems for chemical, steel and power generation plants, but is also a communication method suitable for OA equipment. Regarding

[Conventional technology]

The conventional communication module, for example, Japanese Patent Laid-Open No. 58-56548 has a one-model one-communication system such as a loop system and a multi-drop system. For this reason, it was not possible to respond organically to the needs of customers.

[Problems to be Solved by the Invention] The above-mentioned conventional techniques have the following problems.

(1) If the loop communication method is applied to a communication system in which responsiveness does not matter, the wiring cost increases.

(2) When a customer's existing communication system is expanded, it is necessary to provide as many models as the number of communication methods, which reduces cost efficiency.

An object of the present invention is to solve the above problems at low cost.

[Means for solving problems]

In the distributed communication module device for performing one of the loop communication method and the multi-drop communication method, the above-described object is to provide a first control circuit for controlling the loop communication method in a communication path in which a plurality of modules are connected in a loop. A second control circuit for controlling a multi-drop communication system in a communication path in which a plurality of modules are coupled in series, and a first storage means having respective programs for operating the first and second control circuits A switching unit for selecting the loop communication system or the multi-drop communication system; a second storage unit for storing selection information generated by selecting the communication system by the switching unit; One of the programs for operating the first or second control circuit is selected based on the selection information stored in the storage means, and It is achieved by having a central processing unit for executing the selected communication scheme.

[Action]

The above-mentioned means, when constructing and expanding the communication system,
It shows a method that enables us to efficiently meet the needs, but since the program and hardware are completely separated and selected by the manual switch, there is no malfunction.

〔Example〕

 An embodiment of the present invention will be described below.

In FIG. 1, the upper ring communication path 1 and the lower ring communication path 2 are K.
= Hierarchical communication system connected by main switching module 4 (or 3) and standby switching module 3 (or 4) having addresses of 250 (250 ') and 250 (251'), and multidrop bus An example of a multi-drop communication channel system connected by 21 will be described. A switching switch 22 is installed in the module 5 to manually switch the ring communication system and the multi-drop communication system. In the ring communication path system (hereinafter referred to as a loop), a bypass switch 6 is connected to the ring communication paths 1 and 2 and is turned on / off by a self-diagnosis circuit 7. A communication signal is input to the communication control circuit 10 while the bypass switch 6 is off. This serial signal is input to the communication control LSI 11. A signal is input to the communication control LSI 11 from the clock synchronization circuit 12, and the DMAC 13, CPU 15, and RAM 17 are connected by a bus line. The signals transmitted through the ring communication paths 1 and 2 are input to the communication control LSI 11 and at the same time send an interrupt signal to the DMAC 13, and the communication information is transmitted from the communication control LSI 11 to the RAM 17 without passing through the CPU 15. In the multi-drop communication path system (hereinafter, referred to as multi-drop), the bypass switch 6 is connected to the multi-drop bus 21 and the self-diagnosis circuit 7 turns it on.
Turn off. A communication signal is input to the communication control circuit 20 while the bypass switch 6 is off. This serial signal is input to the communication control LSI 11.

Next, the switching of the communication method, which is the center of this embodiment, will be described in detail. First, the communication path system is switched and selected by the switches 22, 23, 24, 25 and 26 before the power of the module is turned on. In this switch, all the switch contacts are operated at the same time by one operation, and the positions are maintained. Switching switch 22 to 25
The contact is a contact, and the switch 26 contact is b contact. a
Switch to the contact operation direction Select switches 22 to 26 when multi-drop operation is performed, and select reverse loop when operated in the opposite direction. First, by the operation of the switching switch contact 22,
Vcc is input to the I / O port of the process input / output LSI 18. C
The PU 15 reads this port and records the selection result in the RAM 17. During program execution This recording selects the multidrop program and loop program. Next, the switching switch contacts 22 and 26 are used to switch the input line to the clock synchronization circuit from the loop communication control circuit 10 to the multidrop communication control circuit 20. Also, the switching switch 24 contacts switch the reception line to the communication control LSI 11, and the switching switch 25 contacts switch the transmission line.

FIG. 2 shows an embodiment of a method for selecting the loop program 37 and the multidrop program 38. By the RESTART routine, the result of communication method selection is sent to RAM1 as described above.
Record 31 to 9. Next, select the communication method 3
2, 33 processing is executed, and management processing 34, 35 programs are executed. In this state, the flag interrupt or timer interrupt causes the IRQ routine to operate, and depending on the communication system, 36,
Each transmission / reception program 37, 38 is operated. During this time, interrupts are disabled. When the processing of the transmission / reception program ends, the interrupt is released and the RESTART routine management processing 34, 35 is executed.

〔The invention's effect〕

 The present invention has the following effects.

(1) There is no need to make a model according to the communication method, which is advantageous in terms of cost.

(2) One model can meet customer requirements or system needs.

(3) Even if one of the communication control circuits fails, the other communication method can be used, and the utility value as a product is great.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a ring communication path system and a multidrop system according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a communication system selection procedure. 1 …… Higher circular communication channel, 2 …… Lower circular communication channel, 5 ……
Module, 10, 20 ... Communication control circuit, 11 ... Communication control LSI, 15 ... CPU, 22-26 ... Switching switch, 21 ... Multi drop bus, 37 ... Loop communication transmission / reception program.

Claims (1)

[Claims] 1. A first control circuit for controlling a loop communication system in a communication path in which a plurality of modules are connected in a loop in a distributed communication module device for performing one of a loop communication system and a multi-drop communication system. A second control circuit for controlling a multi-drop communication system in a communication path in which a plurality of modules are coupled in series, and a first memory provided with each program for operating the first and second control circuits Means, switching means for selecting the loop communication method or the multi-drop communication method, second storage means for storing selection information generated by selecting the communication method by the switching means, and the second storage means. Selecting one of the programs for operating the first or second control circuit based on the selection information stored in the storage means of Loop / multidrop combined communication module apparatus characterized by having a central processing unit for executing the selected communication scheme.