Communication between PLC5/80 DH+ & SLC5/05 TCP/IP?

[SCADA_Dude]

I've got a tough integration question (for me anyway)

I have an existing DH+ network. I am installing a new SLC5/05 on an ethernet network that needs some information from a PLC5/80 on the DH+ network. Any ideas?

I cant seem to find a gateway that will allow the SLC to communicate with the DH+ network. There is only one open comm port on the PLC5/80 thats used for programming. I've heard the Ethernet card for the PLC5 stinks, is that true?

Thanks!

 

[Ken Roach]

There are three ways I can think of to solve this problem.

1. Add Ethernet to the PLC-5/80. The 1785-ENET only has about half the throughput of the native Ethernet port on a PLC-5E, but that hardly qualifies as "stinks". Who have you been talking to that maligns innocent modules ?

Drawbacks to this method include the cost (a couple thousand), the fact that you might have to upgrade the firmware in your PLC-5/80 to be compatible with the 1785-ENET, and the fact that you need an available slot next to the PLC-5.

2. Add Ethernet to the PLC-5/80 via a serial interface. The 1761-NET-AIC module can connect to the PLC-5/80 Channel 0 serial port and convert DF1 Full Duplex to EtherNet/IP messaging.

The 1761-NET-ENI is about a third of the cost of the 1785-ENET, but is much slower because it has to process all the Ethernet traffic through the DF1 RS232 port. And the open comm port you referred to on the PLC-5/80 might be the RS232 Channel 0 port you already use for programming.

3. Use a ControlLogix family gateway. Connect a 1756-DHRIO module to the DH+ network, and connect a 1756-ENBT module to the Ethernet network. The SLC-5/05 will be able to send a "Multi-Hop" message through the gateway to the PLC-5/80.

This is the most elegant but probably the most expensive method, depending on how much ControlLogix gear you have in the vicinity.

 

[Ken Moore]

If you have any thing else that could benefit from Ethernet connectivity to your DH+ network(s), such as historians, report packages etc...
Then go with the CLX bridge. I installed one last fall, and it's great. I can see everything in the plant now from my office. The only thing I can't do is program DH+ panel views via the bridge. ( I can live with that!).

 

[SCADA_Dude]

Thanks so much for the advice. I will go the Control Logix Gateway route as it seems to fit best with our future plans for the rest of the plant. On a side note, is it then possible to have the Control Logix address the PLC5 RIO racks?

 

[Ken Moore]

Can you expand on that question?

For the ControlLogix bridge, you only need:
1. Chassis with power supply.
2. ENBT module
3. DHRIO module
(no processor required)


If you are wanting to re-use older remote I/O chassis and modules with a CLX processor you can via the DHRIO module. However, there are some gotcha's with analog modules, many folks recommend switching to Control Net.

I have not done a PLC-5 to CLX migration, but there are many post in the forum about it, a search should turn up many hits.