How to communicate between Siemens S7-1200 and Allen-Bradley MicroLogix 1400?

[ulotrichous]

Hi everyone, I'm working on a project where I need to exchange data between a Siemens S7-1200 PLC and an Allen-Bradley MicroLogix 1400 PLC. The Siemens PLC is the master and the AB PLC is the slave. The data consists of a few integers and booleans, and the communication needs to be fast and reliable. I'm looking for the best way to achieve this, and I'm considering the following options:

• Using an Ethernet/IP adapter module for the Siemens PLC, such as the CM 1243-5, and configuring the AB PLC as an Ethernet/IP scanner. This would allow me to use the standard Ethernet/IP protocol to read and write data between the PLCs, but I'm not sure about the compatibility and performance of this solution.

• Using a Modbus TCP adapter module for the Siemens PLC, such as the CM 1241, and configuring the AB PLC as a Modbus TCP client. This would allow me to use the widely used Modbus TCP protocol to exchange data between the PLCs, but I'm not sure about the ease and flexibility of this solution.

• Using a serial communication module for the Siemens PLC, such as the CM 1242-5, and connecting it to the RS-232 port of the AB PLC. This would allow me to use a custom protocol to send and receive data between the PLCs, but I'm not sure about the speed and reliability of this solution.

Has anyone here tried any of these options, or have any other suggestions? I would appreciate any advice or feedback from fellow PLC experts. Thank you for reading my thread and I hope to hear from you soon.

 

[Puddle]

You don't need an adapter for Modbus TCP on an S7-1200, just use the onboard network port. I would imagine this is the best option.

CM-1241 has a 9-pin serial port for RS232/422/485.
There are several varieties of CM-1242 and CM-1243 and most are for Profibus communication.

 

[drbitboy]

I agree with @Puddle.

> Has anyone here tried any of these options

I have implemented Modbus TCP between MicroLogix and S7 PLCs: it is generally reliable; it is also straightforward to set up once the Kool Aid on either side has been ingested.

> the communication needs to be fast ...

Modbus is a polling protocol, which limits the speed, so it suitability depends what is meant by "needs to be fast" for this application. I suspect that over TCP/IP the data rate will be adequate, since a likely slower serial option is also on the table.

> The Siemens PLC is the master and the AB PLC is the slave ... [considering] configuring the AB PLC as a Modbus TCP client.

The client is usually synonymous with the master; the server is usually synonymous with the slave. However, the master/client should be the device that "needs" to know if the communication fails (e.g. network cable disconnected); if both systems need to know then there should be a heartbeat bit so both sides can monitor the connection.

 

[mk42]

Not gonna lie, this part below reads a bit like ChatGPT. These three modules don't have the functions you mention, even tho it has all the right key words. Siemens doesn't sell dedicated communication modules for EIP or Modbus TCP, they do the communication via instructions. Modbus TCP is built in, and EIP requires a library downloaded from the support site. You can either use the built in ethernet port or add an extra. Serial requires an RS232 card, not the Profibus card.

• Using an Ethernet/IP adapter module for the Siemens PLC, such as the CM 1243-5, and configuring the AB PLC as an Ethernet/IP scanner. This would allow me to use the standard Ethernet/IP protocol to read and write data between the PLCs, but I'm not sure about the compatibility and performance of this solution.

• Using a Modbus TCP adapter module for the Siemens PLC, such as the CM 1241, and configuring the AB PLC as a Modbus TCP client. This would allow me to use the widely used Modbus TCP protocol to exchange data between the PLCs, but I'm not sure about the ease and flexibility of this solution.

• Using a serial communication module for the Siemens PLC, such as the CM 1242-5, and connecting it to the RS-232 port of the AB PLC. This would allow me to use a custom protocol to send and receive data between the PLCs, but I'm not sure about the speed and reliability of this solution.

Instead of an in rack module, I typically use a gateway. I often use hilscher nettaps, but anybus is also popular. I think Siemens came out with one a couple years ago, a PN/MF coupler. These devices translate PLC A's preferred protocol into PLC B's preferred protocol, and they do it pretty much in real time. It's way easier than messing around with trying to get things to work in software in the PLC.

 

[Manglemender]

In addition to the anybus and hilscher modules mentioned above, I've also recently been using little Exor panels as gateways to handle comms between Siemens plcs on Profinet and Omron PLCs on Ethercat. Exor panel

 

[Ken Moore]

I have setup and used Modbus TCP between S7-1200's and ML-1400 many times, it very straight forward. Reasonably fast. Both natively support Modbus TCP, so no additional cost. If you want to spend money, perhaps a RedLion Data station.

 

[tarik1978]

CIP Client – exchanging process data with third party control systems:​

SIOS

support.industry.siemens.com

 

[iLikeWaffles]

I've used the Prosoft PLX31-EIP-PND Gateway with good results. They are expensive though.

 

[ulotrichous]

Not gonna lie, this part below reads a bit like ChatGPT. These three modules don't have the functions you mention, even tho it has all the right key words. Siemens doesn't sell dedicated communication modules for EIP or Modbus TCP, they do the communication via instructions. Modbus TCP is built in, and EIP requires a library downloaded from the support site. You can either use the built in ethernet port or add an extra. Serial requires an RS232 card, not the Profibus card.


Instead of an in rack module, I typically use a gateway. I often use hilscher nettaps, but anybus is also popular. I think Siemens came out with one a couple years ago, a PN/MF coupler. These devices translate PLC A's preferred protocol into PLC B's preferred protocol, and they do it pretty much in real time. It's way easier than messing around with trying to get things to work in software in the PLC. geometry dash

I know it sounds like chatgpt but it's actually my issue right now. Anyway, thank you for all your help, I think that I know what I'm gonna do