RS232 Communications in ControlLogix

MorphuisOGrady · Feb 18, 2008

Hi Guys,

Part of a project requires me to communicate via RS232 with 2 special sensors using a ControlLogix L-61.

What are my options? i.e I have only one DF-1 port on CPU. Do I purchase a Micrologix to handle the other one and messgae it or can someone suggest a better approach.

I have never written any code for RS232 communications. Is this complicated? Can someone suggest a starting point for me?

Thanks

diat150 · Feb 18, 2008

check into prosoft cards to do the communications for you. it slides into the controllogix rack. im assuming these sensors communicate via modbus.

http://www.prosoft-technology.com/

MorphuisOGrady · Feb 18, 2008

Nope. They do not communicate via Modbus. I have a feeling this is going to be a right headache.

Have you ever used a rockwell RS232 Port splitter

JHarris · Feb 18, 2008

I've used a serial multiplexer with success. Do a few web searches and see what you find. One vendor is: http://www.tomantron.com/

Regards,

Justin

Archie · Feb 18, 2008

To my knowledge, and I may be wrong since I have never used one, but I think the port splitter only supports DF1 protocol. If your sensors are only ASCII output, I don't think it would work.

Is there a PC on the system that is used for an HMI? If so, maybe you can feed the sensors into RS232 ports on it and then have the HMI write the result to the ControlLogix.

curlyandshemp · Feb 18, 2008

MorphuisOGrady said:
Hi Guys,

Part of a project requires me to communicate via RS232 with 2 special sensors using a ControlLogix L-61.

What are my options? i.e I have only one DF-1 port on CPU. Do I purchase a Micrologix to handle the other one and messgae it or can someone suggest a better approach.

I have never written any code for RS232 communications. Is this complicated? Can someone suggest a starting point for me?

Thanks

Do these special sensors have a unique serial address?. A port splitter, or a RS232 to 422/485 coverter would work only if the devices have unique addressing. Which sensor is going to know it is being interrogating , assuming its a bi directional interface. On a SLC or a PLC5, this would have been an ideal application for the Basic Cards. I beleive Prosoft make a generic Basic card

JHarris · Feb 18, 2008

Update on my earlier post - I used a B&B Electronics (http://www.bb-elec.com) splitter. It worked great. I used it to read/write ASCII data to multiple devices. They call them "Serial Port Combiners." Note the 12VDC power requirement.

Regards,

Justin

JHarris · Feb 18, 2008

curlyandshemp said:
Do these special sensors have a unique serial address?. A port splitter, or a RS232 to 422/485 coverter would work only if the devices have unique addressing. Which sensor is going to know it is being interrogating , assuming its a bi directional interface.

Check out B&B Electronics Serial Data Switches (Cat.#232MSS2 for example). Whether this will work depends on the application requirements which we don't have all the details (do you need continuous read/writes to both devices simultaneously?)

MorphuisOGrady · Feb 18, 2008

Good Idea!

That is exactly how it works. The sensors use a program called AquaPro which communicates over RS232. Now any suggestions on how I could get the data from AquaPro and into my CLX

Archie said:
To my knowledge, and I may be wrong since I have never used one, but I think the port splitter only supports DF1 protocol. If your sensors are only ASCII output, I don't think it would work.

Is there a PC on the system that is used for an HMI? If so, maybe you can feed the sensors into RS232 ports on it and then have the HMI write the result to the ControlLogix.

TConnolly · Feb 18, 2008

Do you have device-net or e-net availalbe?

AB and Beckhoff make modules that communicate with RS-232 sensors that furnish the information back to the PLC over device-net IO or ethernet IO.

This keeps your serial port free as a programming port.

http://www.ab.com/io/download/1734-232ascapp.pdf

http://www.beckhoff.com/english.asp?busterm/kl6001.htm

kamenges · Feb 18, 2008

Originally posted by MorphuisOGrady:

Now any suggestions on how I could get the data from AquaPro and into my CLX

OPC using KEPWare or RSLinx OEM over Ethernet? I don't know what you can get out of AquaPro and their website doesn't say much.

However, I would go with the ProSoft card or Alaric's suggestion or a stand-alone serial port on a bus. Alaric's suggestion would be especially attractive if you already have an Ethernet bridge or DeviceNet scanner and you go Beckhoff.

Keith

RS232 Communications in ControlLogix

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