PLC5 upgrade to Control Logix

[grider75]

I am working on upgrading all of our PLC5's to Control logix. My current project has a PLC remote rack 500 feet away from the main rack. There is already a dh+ cable in place for the PLC out to the remote rack. I know the preferred method of connecting a remote rack in control logix is Ethernet, but due to the distance I was going to try and use the dh+ to save time and money, but having issues getting it to see the rack in my program. Is this even possible? Do I need to pull fiber out to this remote rack? Please let me know if I can do this and how to set up the communication's. Thanks

 

[jkerekes]

Is this a remote PLC rack with just I/O in it OR a remote PLC? Because DH+ is not for remote I/O. If its remote I/O using RIO, which is implemented on the same type of cable as DH+, you can use a 1756-DHRIO or better yet a 1756-RIO module.

 

[Paullys50]

You'll need to provide more detail. What exactly is the remote rack? Is it a PLC5 Chassis w/an adaptor? Or did you install something like FlexIO or PointIO? Or is it a ControlLogix rack w/an adaptor?

You cannot use DH+ for IO. However, DH+ shares the same "Blue Hose" as an RIO network (which is typical for older PLC5 systems). If your remote rack is a PLC5 rack w/a 1771-ASB then you need to use RIO protocal. The CLX would require a 1756-DHRIO, or 1756-RIO card to communicate w/the remote rack. This is a bit to configure in a ControlLogix, but not too bad. Read manuals.

EDIT: Beaten to the punch...

 

[grider75]

Is this a remote PLC rack with just I/O in it OR a remote PLC? Because DH+ is not for remote I/O. If its remote I/O using RIO, which is implemented on the same type of cable as DH+, you can use a 1756-DHRIO or better yet a 1756-RIO module.

I am wanting to add a remote I/O rack to a Control logix. The remote rack I have set up for testing has a 1756-DHRIO card and some I/o cards. The main rack also has a 1756-DHRIO card. I have them both set up as dh+ communications on channel A. I can see my remote rack and cards in RSlinx through my main rack DHRIO card, but have a communication error in my program where I added my DHRIO card to the I/O configuration. Error is 16#ff00 No connection instance.

 

[grider75]

You'll need to provide more detail. What exactly is the remote rack? Is it a PLC5 Chassis w/an adaptor? Or did you install something like FlexIO or PointIO? Or is it a ControlLogix rack w/an adaptor?

You cannot use DH+ for IO. However, DH+ shares the same "Blue Hose" as an RIO network (which is typical for older PLC5 systems). If your remote rack is a PLC5 rack w/a 1771-ASB then you need to use RIO protocal. The CLX would require a 1756-DHRIO, or 1756-RIO card to communicate w/the remote rack. This is a bit to configure in a ControlLogix, but not too bad. Read manuals.

EDIT: Beaten to the punch...

Ok, so I cannot add a control logix remote I/o rack with dh+? Guess im pulling fiber out there.

 

[jkerekes]

You didn't answer our questions. You currently can't be using DH+ to communicate with any remote I/O. DH+ is for peer to peer communication. What hardware do you have in that remote PLC rack?

 

[Paullys50]

RIO would be your only option to re-use the "blue" hose. It is an obsolete protocol for IO.

To my knowledge, you cannot use a 1756-DHRIO or 1756-RIO card as a "slave". Your proposed setup won't work. Yes you will need to use Ethernet if you intend to use the CLX rack (ControlNet, DeviceNet could be options).

 

[grider75]

You didn't answer our questions. You currently can't be using DH+ to communicate with any remote I/O. DH+ is for peer to peer communication. What hardware do you have in that remote PLC rack?

The remote rack I have set up for testing has a 1756-DHRIO,1756-IA16,1756-OW16I, 1756-IF16H

 

[jkerekes]

As Paully said, you can't use DHRIOs or DH+ that way.

 

[mellis]

If the remote rack was an existing 1771 rack with a 1771-ASB module, THEN you could use a 1756-DHRIO module in the processor rack to talk to the remote rack over RIO using the existing cable. As far as I know, there is no 1756 series RIO adapter module that you could put in a remote rack.

You need a processor on both ends to use DH+.

 

[JeremyM]

+1 for Ethernet/IP.

I'm assuming both racks are of the 1756 line. Concerning the distance, a switch placed between the two racks outfitted with 1756-EN2T (or a variant) would overcome the distance limit of CAT 5E cabling, or you can employ a 1756-EN2F in each rack and use fiber to connect each bridge directly.

 

[Operaghost]

He is going from a 1756 chassis to another 1756 chassis using the DHRIO modules. Look at post #8. DH+ obviously does not support what he is attempting (no I/O over DH+) so he needs change the dial settings on the DHRIO to use Universal Remote I/O Scanner Mode in the main chassis and Adapter Mode in the remote.

He wants to use an old network and an old protocol so he can reuse the cabling? This should be EtherNet/IP.


OG