This is my first time to use Unity Pro S and M340 PLC. I have to connect my Automation Direct C-more HMI to PLC using Modbus TCP/IP. Is there any setting in Unity Pro or M340 to enable Modbus messaging? Which function block I have to use for the setup. My PLC CPU module has build-in Ethernet port for Modbus communication. Thanks
Programming M340 with Modbus TCP/IP
- Thread starter Forrest
- Start date
robertkjonesjr
Member
As a ModbusTCP server, which the PLC usually is when connected to an HMI, it should just work out of the box. You don't need any special function blocks to make it service the requests - only be sure the network parameters are configured properly for the device in Unity.
Hi Robertkjonesjr: Network parameters are configured and there is no communication error in connection between HMI and PLC.
That's meant, for example, I just create an indicator in HMI and set the address to 10001. It can read the input with address %I0.1.0 in PLC directly. Am I right? Thanks
That's meant, for example, I just create an indicator in HMI and set the address to 10001. It can read the input with address %I0.1.0 in PLC directly. Am I right? Thanks
Last edited:
robertkjonesjr
Member
Yes, according to the mapping. I am not certain without looking in the manual what 10001 is mapped to, but whatever it is, it should be available to you without any additional work on your part.
No 10001 is not mapped by default to %I0.1.0
In the plc you will need to map your data to %M or %MW addresses
If using an Modbus driver then read %M0 using 00001 and %MW0 using 40001
Note the 1 offset - why I prefer to use modbus drivers that support iec addressing
In the plc you will need to map your data to %M or %MW addresses
If using an Modbus driver then read %M0 using 00001 and %MW0 using 40001
Note the 1 offset - why I prefer to use modbus drivers that support iec addressing
danw
Lifetime Supporting Member
>Note the 1 offset - why I prefer to use modbus drivers that support iec addressing
GeoffC,
Can you tell me which IEC document is involved with Modbus addressing?
5 minutes later:
I knew I'd looked into this before, just a year ago in July on this thread:
http://www.plctalk.net/qanda/showthread.php?t=56516
GeoffC,
Can you tell me which IEC document is involved with Modbus addressing?
5 minutes later:
I knew I'd looked into this before, just a year ago in July on this thread:
http://www.plctalk.net/qanda/showthread.php?t=56516
Last edited:
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