Author Topic: Discovering PLCID via TBasic?  (Read 13423 times)

Joel Moore

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Discovering PLCID via TBasic?
« on: March 24, 2004, 01:30:27 PM »
Is there a way for an M-series PLC to determine it's own PLCID via TBasic?

I want to interact with the PLC via the RS485 port but I also want to put other devices (namely the ICP I-7018 thermocouple module) on the same RS485 line.  Unfortunately, ICP has chosen to use their own protocol rather than implementing MODBUS so I was hoping to write some TBasic code that can figure out how to handle ICP-style messages that are addressed to the PLC's ID.  But I want the PLC to be able to handle whatever address is assigned to it in case I have several PLC's on the line.

Or does anyone have any other ideas for dealing with this situation?  I find it really frustrating when companies offer products that use RS485 but don't adhere to any of the standard protocols for communicating on party lines.  Are they so egocentric that they think people have no need for other company's products in their applications?  Sure, I could add a second RS485 port to deal with ICP's modules but this is added complexity (and cost and wiring) that I really don't need.

support

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Re:Discovering PLCID via TBasic?
« Reply #1 on: March 24, 2004, 03:37:42 PM »
The PLC can find out its own ID using the 'status(8) ' function.

Our M-series PLC supports MODBUS ASCII, MODBUS RTU, OMRON and our own native protocols so it a very flexible platform.
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Joel Moore

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Re:Discovering PLCID via TBasic?
« Reply #2 on: March 24, 2004, 04:00:58 PM »
Thanks.

Trust me, I wasn't compaining about your PLCs.  I agree that they are very flexible.

I was complaining about ICP (and other companies in general) not supporting MODBUS when they support RS485.  However I've since learned from ICP that they plan on offering MODBUS in the I7018 (and maybe others?  I didn't ask.) by June so I may have an elegant solution after all.


support

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Re:Discovering PLCID via TBasic?
« Reply #3 on: March 24, 2004, 04:14:56 PM »
That will be good news. It'll also make it easier for the M-series PLC to talk to modbus based I-70xx (if it is true) since M-series PLC has built-in support for reading from a MODBUS slave. I agree it is more elegant solution since multiple devices from different manufacturers can all be connected on the same twisted pair cable.
« Last Edit: March 24, 2004, 04:15:51 PM by support »
Email: support@triplc.com
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Joel Moore

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Re:Discovering PLCID via TBasic?
« Reply #4 on: March 25, 2004, 03:35:52 PM »
According to the person I talked to at ICP today (John Gong) they are going to start beta testing the MODBUS stuff on several of their analog modules next week (again, sorry, I don't know exactly which models -- I'm mainly interested in the I-7018 module) and he said they'll probably be adding MODBUS to their other modules in the future.

Oh, and he also had good things to say about you guys.  :)