Multiple Redlion HMIs to A-B SLC PLC

I want to connect two Redlions (G306) to an Allen-Bradley SLC 5-03 PLC.

I want to keep one port free on the PLC for programming purposes, so I would like to have both HMIs communicating to the PLC via the same Comms port (probably RS485).

Can anyone (especially anyone from Redlion) can advise if this is recommneded and/or practical?



N.B. What I don't want to do, is have one HMI connected to the PLC, and then passing data onto the second HMI, because if the first HMI fails, then the second HMI is rendered useless.

you cant have two masters on a 485 bus without using some sort of splitter that is designed for that purpose.

Would an Allen-Bradley 1761 AIC module work?

At the moment, all our panel builder is getting told from his distributer & Red-Lion rep, is that RS232 link between HMI-1 & PLC, and Ethernet Server-Client link between HMIs is the only recommnended solution.

Which as I have already stated, is not an acceptable solution.

Any suggestions, anyone?

in your case since you dont want to do the server client thing I would look at maybe using a digi one iap to convert serial to ethernet then use the ethernet port for both hmi to communicate to the plc.

Yes, it will work. You just need to make sure that each G3 has its own address. You set the G3's address by clicking on the 485 Comms Port. The "Station Number of Terminal" is the G3s address. I currently have a SLC 503, address 1, a G310 with an address of 2, and a G310V2 with an address of 3, and they are all talking.

Regards,
Dan

DH485 is a token passing network where each node takes a turn as the master.

Perhaps that's the reason for Red Lion to name the driver "DH485 Master"?

Not trying to hijack, but Dan, can you comment on this thread about why this protocol doesn't appear to support the 5/01 and 5/02?

Dan,

Just to clarify things:
Is that Yes that will work if I do use the A-B 1746 AIC module?

Or is Yes it will work, without needing to use the AIC module?

Regards,

Marc

It will work without needing the AIC. For my test, I used the following:

CBLAB003: http://www.redlion.net/Support/Cable/CBLAB003.pdf

connected between the PLC and a:

DRRJ45P6: http://www.redlion.net/Products/Groups/Archive/DRAdaptersandCables/Docs/12036.pdf

Then from that I connected 2 straight through Ethernet cables to the 2 G3s' 485 ports.

Regards,
Dan