Connecting Remote IO to PLCs over Modbus

The iR-ETN firmware supports Modbus TCP/IP protocol.

Launch Remote IO

Inside Remote IO go to the Online tab and click [Automatic Scan] to scan the network for the iR-ETN coupler. The information of the iR-ETN and the connected modules is show as below.

The default IP of a iR-ETN is 192.168.0.212. Please make sure the PC is on the same subnet.

The iR-ETN can be found in Automatic Scan window. Select the iR-ETN you want to configure and click OK.

The iR-ETN and the module’s information will be shown as below.

Select [Change IP] under [Edit] to change the IP address of the iR-ETN and then click OK.

In the Project Window, select an iR-ETN and then go to the [Parameter] tab in the right column. Here you can change the related parameters of the iR-ETN. The actual value of the iR-ETN is in the [Online Value] column. The new value should be entered in the [Project Value] column.

Click [Upload] to read the data from the iR-ETN coupler and present it in EasyRemote IO.

Click [Download] to write the data in EasyRemote IO to the iR-ETN coupler.

* The Maple Modular PLC DOES have Modbus TCP Master capabilities but you have to use the MOD-SENT01 Ethernet module perform this feature.

Launch MapleLogic

Create a new project and select PLC-ES as the CPU type.

Right click on [Program] and select [New Program].

Select [MODBUS/TCP Master] under Communication Configuration. Name your program, and choose an ID number then click [OK].

A Special Function window will open. Click [New] to enter the iR-ETN IP address then click OK. Ensure the slot number is configured to Slot1 then click [Save].

Next add a Data Block to communicate with the Analog Input Channel on the slave device. Click [Add] and choose the function “03 Read Holding Registers (4x)” with the Start Address of “2” click [OK], then click [Save].

Now, configure the Modbus TCP Master IP address. Under [Parameter], click the [Ethernet] tab. Enter the Modbus Master IP address then click [OK].

Lastly, configure the MOD-SENT01 Ethernet Module. To do so first, [Connect and Download] to the Maple Systems Modular PLC. Next, under [Card Properties] double click the MOD-SENT01 card. A Setup Ethernet Module window will appear.

For Slot: select Slot1 as this is the slot number for the Ethernet Module. Ensure the IP address matches the TCP Master Device. Set the MODBUS Unit ID to 1 then click [Write] followed by [Close].

Configuring Logic

Using the steps above a project should have been created and downloaded for the Maple Systems iR-ETN coupler, and Maple Systems Modular PLC. Both devices should be communicating to proceed with this section of the article.

Right click on [Program] and select [New Program]. Select [Scan] under the LD Program column. Next, give it a Program Name, and ID.

Inside the Special Function program add a Data Block to communicate with the Analog Input Channel on the slave device.
Click [Add] and choose the function “05 Force Single Coil (0x)” with the Start Address of “1” pointed at the PLC Device value of “Y0004”. Click [OK], then click [Save].

Right click on R.1 and insert a row above.

Next, double click the first rung block to place instructions. For this example type > into the field. This will generate a S1 is greater than S2 instruction where the S1 and S2 operands can be configured below.

Modify S1 to be D with a value of 00, and S2 to be a constant with a value of 5000 then click [OK].

On the last rung block create a Coil pointed at the register-address of Y04.

The first output on the iR-ENT’s DM16-N module will be turned on when the AI04-VI’s Analog Channel 1 is above the 5000 limit. For this example when the signal generator supplies 6.270mA.

Demo Project Download

• MapleLogic_Demo_Project
• EasyRemoteIO_Demo_Project