CLX - Local IO in another chassis

Hi,
Does anybody know what's the equivalent Local IO Extension Module of PLC-5 series (1771-ALX) into CLX (1756 series)?

Does the 1756 series have any option for Local Chassis extension at all? I tried to search in most of the Rockwell Documents about this but they have always mentioned about Remote IO Chassis using CNET/ENET etc.

Your help in this regard would be appreciated.

Thanks in Advance.

Regards,
--Rahul.

There is none that I am aware of.

Why would you need that in a ControlLogix system?

There is no extended local i/o in the CLX family. Use EtherNet/IP or ControlNet and you can get equivalent performance.

OG

To the best of my understanding it would be difficult to get clogix backplane performance accross a interconnect cable.

But if he describes "why" he needs this, we could provide MUCH better responses instead of guessing. I never used the extended backplane PLC5 processors, so I don't know what their performance would be relative to what you can do with ControlLogix with either a CN or Ethernet I/O. with a 17 slot rack you can have 16 slots of local I/O.

Confirmed: There is no "extension" cable for the 1756 backplane.

Related:

For a PLC-5 to ControlLogix migration a few years ago I did a speed test comparing local block transfers in the PLC-5 to a ControlNet scheduled connection to a remote 1756 chassis.

With just two adapters on the ControlNet, running the default 5 ms RPI, I was able to match or exceed the update rate of a local block transfer. I think the modules I was comparing were 1771-IFE and 1756-IF6I.

The ControlBus backplane runs too fast to be extensible; the length of a 17-slot chassis is pretty much what it can do.

I haven't encountered any applications where I needed local I/O performance and couldn't either fit the I/O into local chassis or connect them with a dedicated fast network link.

Ken Roach said:

With just two adapters on the ControlNet, running the default 5 ms RPI, I was able to match or exceed the update rate of a local block transfer.

Click to expand...

Ken, what do you mean by the two adapters on CN? Do you mean the I/O modules?

jkerekes said:

Ken, what do you mean by the two adapters on CN? Do you mean the I/O modules?

Click to expand...

He means one 1756-CNB (or CNBR, or CN2, or CN2R) in the local chassis, and one 1756-CNB (et al) in the remote chassis.

I've got semi-large ControlLogix systems here, running many remote I/O chassis, with a mixture of full 1756 chassis, Point I/O, and Flex, and have no issues with speed. A typical line has 5 1756-A17 Chassis, 7 Flex IO with 5 to 8 modules each, and another 10 to 15 Point I/O drops, all including smart (complex) I/O modules such as counters and analogs.

On Largish systems, the only thing I do do, just to make things logically cleaner, is to separate out my I/O ControlNet, and the Drives ControlNet. I use separate networks there.

Ken Roach said:

Confirmed: There is no "extension" cable for the 1756 backplane.

Related:

For a PLC-5 to ControlLogix migration a few years ago I did a speed test comparing local block transfers in the PLC-5 to a ControlNet scheduled connection to a remote 1756 chassis.

With just two adapters on the ControlNet, running the default 5 ms RPI, I was able to match or exceed the update rate of a local block transfer. I think the modules I was comparing were 1771-IFE and 1756-IF6I.

The ControlBus backplane runs too fast to be extensible; the length of a 17-slot chassis is pretty much what it can do.

I haven't encountered any applications where I needed local I/O performance and couldn't either fit the I/O into local chassis or connect them with a dedicated fast network link.

Click to expand...

Thanks Ken!
I was looking for the Local IO extension option because it's a pain to convince the EPC involved in the project I am working on about keeping the plant EtherNET traffic away from these kind of dedicated networks like remote IO connected on EtherNET.

Now they don't want to use ControlNET for remote IO connectivity. So we proposed the EtherNET for remote IO which got accepted by them however they want to connect all these to a single Stratix switch (1783-MS06T). After explaining them about keeping the remote IO isolated from any other Ethernet data; they asked us to connect different EtherNET networks having different Subnets to the same switch and according to them it should not affect/interfere with each other. I am not an IT/Network guy so would like to know whether it can be achieved this way.

Another thing is does this switch 1783-MS06T work with single mode fibre cable for its fibre port(s)?

I would appreciate if you could shed some light on these questions.

Thanks in advance!

Regards,
--Rahul.

Yes you can do that with stratix 8000 series it's called a Vlan. may not be necessary though. How much IO are we talking?

Whats the layout ? How many racks / ENBT and is there and HMI? How Many?

Depening on the firmware you flash your processor with (19 i think) you can use unicast for the IO connections and you won't have all that multicast traffic to deal with.

The Plc Kid said:

Yes you can do that with stratix 8000 series it's called a Vlan. may not be necessary though. How much IO are we talking?

Whats the layout ? How many racks / ENBT and is there and HMI? How Many?

Depening on the firmware you flash your processor with (19 i think) you can use unicast for the IO connections and you won't have all that multicast traffic to deal with.

Click to expand...

Thanks, The Plc Kid!!

Regards,
--Rahul.