RS485 PLC Link Service

Outline

CM1-SC01A/SC01B/SC02A card are used for this service, which is the protocol using a RS485 Network to exchange data between the CIMON PLCs. The specifications are as follows.

• Maximum connected PLCs : 32 units

• Up to 32 sending blocks per PLC can be assigned.

• The interval of communication for each sending block can be set up in the range from 50ms to 3s.

• The data of up to 64 words per one sending block can be sent.

• The number of the communication blocks assigned to each PLC, summing receiving blocks and sending blocks, is up to 64.

• The necessary blocks selected among the sending blocks of other PLCs in a network are assigned to receiving blocks.

Link Points

Processing the Sent Data and the Received Data under PLC Link

An Example is taken to explain how data are processed when they are sent or received under PLC Link.

• Sending Party : This is used to set up the data read, the number of the block where data is sent, data size and sending interval to a sending party in broadcasting method.

• Receiving Party : This is used to set up the station number and block number for the sent data to a receiving party in broadcasting method to receive a desired data.

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[Ex.] Station 0 sends the data of Device D0000 and Station 1 stores received data in Device Y0000.

Open

The block number of a sending party and the one of a receiving party are the same as 0, and the station number of the sending party is set up as 0 like the one of the receiving party. In this condition, the receiving party can receive every 100ms and the data sent from the sending party every 100ms. Though the sending party sends the data of 10-word size, the receiving party selects and receives the necessary data of 4-word size. But, if the size of received data is greater than the size of sent data, the PLC will receive the data as much as the size of the sent data.

Setting up PLC Link Parameter

To run PLC Link and to exchange data between communication modules, the parameter is to be set up in the CICON.

Creating a Project in the CICON

Select the menu to run the CICON and to open a corresponding project.

[Picture 6-1]

Open

Setting up PLC Link Parameter

Selecting PLC Link Parameter:
If you select the PLC Link on the window like [Picture 6-1], a PLC link dialog box
will appear. In the dialog box, up to 4 communication modules can be set up for
one CPU. To set up the PLC Link to a mounted communication module, select Link(0), Link(1), Link(2) and Link(3) on the top of the dialog box and enter the values for each communication module

Setting up PLC Link Type:
PLC Link Type is used to set up basic items such as network type, base, slot number, station number and so on.

[Picture 6-2. PLC Link Setup]

Network
This is used to set up the type of the communication module for PLC Link. If you do not use PLC Link, select the Not Use.
Here, select the RS232C/485.

Base
This is used to select the base where the communication module for PLC Link is mounted. For example, if there is no expansion base (The base where a expansion card is mounted), select the Local. If there is expansion base (The base where a expansion card is mounted), select the Expansion Base where the communication module is mounted.

Slot
This is used to select the slot number of the base where a communication module is mounted.

Setting up the communication block for PLC Link:
Communication Block is used to register the information about sending/receiving real data. If you select RS232C/422 as Network and the Add button in [Picure 6-2. PLC Link Setup], a Communication Block dialog box will appear like [Picture 6-3. Communication Block Setup].

[Picture 6-3. Communication Block Setup]

Sending
When communication modules communicate each other, this is used to send a selected block.

Receiving
When communication modules communicate each other, this is used to receive a selected block.

Station No.
When communication modules communicate each other, in case of sending data, it is not necessary to set up station number. But, in case of receiving data, the station number of a receiving communication module is to be selected. The station number can be set up in the range from 0 to 63.

Block No.
The communication modules for a sending party communicate with each peculiar block number. In the same way, the communication modules for a receiving party have each peculiar block number to receive data. The receiving block number is used to detect the data that a receiving party wants together with the station number when the party communicates with a sending party. But, the block number can be set up in the range from 0 to 31. To receive the data of a sending party, the same number is to be set up as the block number for the sending party and the block number for a receiving party.

Sending Interval
The sending interval, the parameter for deciding the interval at which data are sent, can be set up in the range from 50ms to 3sec according to users’ need. For example, if 50 ms is set up as sending interval, the data will be sent every 50ms.

Device to Pick up Data Sent & Device to Store The Received Data (Address):

When sending: This is used to set up the device where the data sent are read.
When receiving: This is used to set up the device where received data are stored.

Device to Pick up Data Sent & Device to Store The Received Data (Size):

This, the size of the data sent or received, can be set up by the word. But, the size is from one word to 64 words. If the data size of a sending device is greater than the size of the data set up to a receiving device, the necessary data as much as the size of the one set up to the receiving device can be received selectively and used.

[Ex.] The communication module of Station 1 sends Block 0, 1, 2 and 3, and receives Block 4, 5, 6 and 7. And the communication module of Station 2 sends Block 4, 5, 6, and 7, receives 0, 1, 2 and 3. An RS232C/422 card is mounted on Slot 4. Each data size is one word and the interval is 50 ms each.
Such case is taken as an example and the PLC link parameter for it is configured as follows.

[Station 1]

Station 1 sends the data of the sending devices from D0000 to D0003 by the word at each interval.
The received data will be written to the corresponding addresses in the receiving devices from Y0000 to Y0030, if the corresponding station and blocks are in accord.

[Station 2]

Enter 2 as the sending station number and 4, 5, 6, 7 as the block number to send at each interval. If so, the RS232C/422 module of Station 1 receives, comparing the receiving station and the blocks.
In the same way, Station 2 compares the numbers of the blocks in the received frames with Block 0, 1, 2, and 3 of Station 1. And if they are the same, Station 2 receives them and writes the data to the devices from Y0000 to Y0030.