Modicon 984/680 requires additional comms port

I'm new to Modicon. We're looking at an application where the client has a Modicon 984/685 series CPU and both comms ports are in use.

We need to be able to connect a HMI to the system now. Short of adding an extra communication module (and I'm not sure if we even have the room to do this if it was possible) would any one have any recommendations as to how we might gain an extra serial port?

Some form of multiplexer perhaps? Any advice is always appreciated.

Regards, Dave

http://www.prolinxgateways.com/content/view/full/8891

Click on this link and see if this is what you are looking for.

I have used some of their other products but not this one so I don't know anything about how it works.

Sid

Your processor has a Modbus Plus port (as well as the two Modbus ports)so you can use any available Modbus Plus to Modbus convertor. For that matter, if your HMI has an ethernet port you can use a Modbus Plus to ethernet convertor

In the old days Modicon called their product a "bridge mux" (part numbers began with NW-BM85). They were stand alone units and did not need rack space.

984 680 has 2 modbus ports

984 685 has 2 modbus and 1 modbus+

which do you have?

Brian

The client has the 680 model, I made a mistake in the earlier post. Thanks for your suggestions guys.

What are the two ports being used for right now?

Can the funciton of one of those ports be handled by an Ascii module or an Ascii/Basic module?

Also try prosoft technologies:
Modbus Master/Slave to Ethernet converter:
http://www.prolinxgateways.com/content/view/full/7003

Generic Modbus to Ascii converter:
http://www.prolinxgateways.com/content/view/full/6909

One port of each goes to a modem for connection to a SCADA system, the other port goes to the electricians office for programming purposes. There are no spare slots in any of the racks

David,
In reference to your last post, please note in the links that Alaric and I posted, these are stand alone modules. They are not used in the rack.

Copy & Paste from a portion of one of the links:

The ProLinx family Modbus TCP/IP to Modbus Master/Slave communications module (4201-MNET-MCM) creates a powerful connection between devices on a Modbus TCP/IP network and Modbus serial devices. The module, encased in either plastic or aluminum (ProLinx Plus 5000 series), is a stand-alone DIN rail-mounted protocol gateway that provides one ethernet port and up to four serial ports.

Sid

David, if the customer is going to be hanging on to these dinosars for a while then I recommend at least bringing the communicaitons up to a level that can operate with todays technology. If you can use a gateway converter to get one of those modbus ports up to Modbus TCP/IP on ethernet then in my opinion that is the way to go to best extend the longevity of these very trusty but old plow horses.

There is also a Quantum option, where the 984 processor is replaced by a scanner and a Quantum is mounted in a new rack - but all of the old 800 IO remains exactly as it is. Your Modicon distributor will have to help you with this - its not the cheapest way to go, but it does preserve all the old IO and wiring and is less than a whole new system. And it gives Connection: closeyour system modern communication abilities.