Communicating thru other PLC's to the main PLC

John Morris · Sep 15, 2015

Hi guys

Probably another rookie question, but here it goes.

OK I assign N110, N111, and N112 to the cpu's 2, 3, and 4, respectively. Ill have alarm inputs from each of these. How do I point them back to CPU1 to halt machine state.

Any help would be appreciated.

Thank you in advance

keshik · Sep 15, 2015

You're probably going to want to say what PLCs you are using, and what communication protocol.

John Morris · Sep 15, 2015

Please accept my apologies.

4 Micro 1400 A, RSEmulator 500, FTV using RSLINX, RSLOGIX

rdrast · Sep 15, 2015

And how are the PLC's communicating with each other?
I would generally just poll all of my slave PLC's from the master with MSG instructions (MSG Read, instructions).

John Morris · Sep 15, 2015

Nice boat BTW

I have two MG90 and an MG91. I'll have to back thru the books and refresh on that one.

Thank you

John Morris · Sep 15, 2015

Ok

Here's a question. I can sim motor overload and a low float. They show up on the HMI. And when I touch reset alarms, I can see the bit N9:0 go hi in CPU1 , but, the cmnds to cpu 2 and 3 are not toggling. its like it a one way street.

Any ideas

Mickey · Sep 15, 2015

Are you trying to do this with RSEmulate?

If so I don't believe the "MGS" instruction is fully supported.

John Morris · Sep 15, 2015

Ok so information comes in but I cannot send it out.

Is that what its telling me?

I can sim alarms and they show upon the HMI, the reset toggles on CPU1 but does not transfer to CPU2,3,or 4. I'm just wondering if I have everything set correctly.

I'll double check

If you can think of any thing else, please forward.

Thank you very much, All, for your valuable time

Saffa · Sep 15, 2015

Is your alarm bit part of a register that is being written back to each of your remote PLCs? You should have a MSG instruction for writing each block of registers to each remote PLC, and another MSG induction for reading registers back. Sounds like you've got the read registers instruction but either no write instructions or that bit isn't included in the range of registers being written.

Post your code from the master PLC and from one of the slaves.

John Morris · Sep 15, 2015

HMmmm

Didn't think of that, Ok i checked the set up screens for the MSG 90, under tab MultiHop, these units are addressed to 192.168.1.12. I removed RS ENterprise, and made RSLinx the primary OPC server in FTV. its emulating DHP. have i crossed two wires here.

Communicating thru other PLC's to the main PLC

John Morris

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