DH+ Long Gone?

I have a DH+ PLC network which has a number of PLC5 & SLC5/04 and control logix, There is also a control logix gateway used for communication to computers for programming and troubleshooting.

Now I personally don't have a problem with the PLC5 line they seldom give trouble and I have so many spare parts I don't see a conversion coming anytime soon so here is the thing. I have a few areas small still hardwired areas I wanna control via PLC and connect to the plant and the Micrologix line seams to be the best way for its size and ability to act as a high speed counter and so on. But I in no way would like these small controllers to be isolated in many is of not all the cases there are data I would liked sent back to the Main PLC5's. I would rather not use the existing control logix gateway (ETH to DH+) because of its location so my question is what are my options.

Desired communications Micrologix 1100,1400 to PLC5/40

Cat 6E is cheap use ethernet and bridge with the CLX.
Why not you don't have to run the cable back to the bridge if you have a plant wide ethernet. I have been looking at Elpro wireless radios to replace my wired systems and for any new installations.

If you look at a radio at let's say $2,000.00 per raidio. 2 units minimum so we are at $4k. What does pipe, wire, and labor cost? On a 50' run it wouldn't be such a good choice. 500' looks real good.

I don't have plant wide Ethernet I have plant wide DH+. The only Ethernet is a control logix gateway that is used to connect the Ethernet network to the DH+ network. The Ethernet network is only used for computers for troubleshooting. The control logix gateway is located to far from the micrologix to be feasible for use to connect to.

For this reason I am looking at the best means of connecting a micrologix to a PLC5. My thoughts thus far are tending towards the 1761-NET-ENI.

Kabir said:

I don't have plant wide Ethernet I have plant wide DH+. The only Ethernet is a control logix gateway that is used to connect the Ethernet network to the DH+ network. The Ethernet network is only used for computers for troubleshooting. The control logix gateway is located to far from the micrologix to be feasible for use to connect to.

For this reason I am looking at the best means of connecting a micrologix to a PLC5. My thoughts thus far are tending towards the 1761-NET-ENI.

Click to expand...

Which is fine, but your still running ethernet so I'm lost as to what your problem is. Your going to put a net-eni in the plc5 too?

compactlogix and controlnet

RS Logix 5000

OK let me see if I can make it clear yes I do have Ethernet. The control logix gateway is located in the package area which is close to the office hence the control logix gateway Ethernet links the package DH+ to the engineering computers (troubleshooting). There is another plant on the other end of the compound that has a DH+ network as well connected to the control logix gateway via DH+. It is inside this plant where I wanna link a PLC5 and a ML1100. So it may not be practical to run Ethernet from all the way across the compound back to the control logix gateway just to send it back to PLC5 in the same plant where the data came from (or is it?).

What I was thinking was a 1761-NET-ENI module connected to the PLC5 to communicate to the ML1100 via Ethernet as my best solution. Now I Realise in this solution I would not be able to go online or download data into the ML1100 however I would still be able to have it send data such as alarms or Machine position to the main PLC5 of that plant.

Kabir said:

I have a few areas small still hardwired areas I wanna control via PLC and connect to the plant and the Micrologix line seams to be the best way for its size and ability to act as a high speed counter and so on. But I in no way would like these small controllers to be isolated in many is of not all the cases there are data I would liked sent back to the Main PLC5's.

Click to expand...

It's hard to say for sure, because I don't know your plant layout or all of your goals, but this sounds to me like a good place to use Flex I/O. We use Flex with RIO adapters (1794-ASB) as remote I/O racks off of PLC/5s all of the time.

The Net-ENI will do the job. They can sometimes be a pain to configure, but once you get through the first one, the others should be quite easy. There is a limit to how many connections they support, and even with only one connection, the quantity of data is still limited by the serial side of things.

If the machines are big enough to need a SLC rack, there is nothing wrong with the 5/04...DH+ is not dead yet...

I am partial to DH+. It works very well for years on end without problems if correctly installed...and troubleshooting is very simple too...that is not the case with ethernet in my experience...

OkiePC looks like you have the same view as I do with respect to DH+ (Maybe not the fastest but simple and reliable). I have a few SLC5/04 in storage but what I was really interested me in the ML1100 was the high speed I/O to use it on some small hard wired machines each with an encoder and some valves (Over Kill for the 5/04 in my thinking). I could program the ML1100 to perform the task in full however the challenge would be to relay information back to the main PLC5.

Thanks for all your comments I am always grateful.
Thinking seriously about NET-ENI connected to the PLC5 then Ethernet to the ML1100's.

Oh I should point out the reason why I asked if DH+ was dead is because I could not seam to find a Rockwell device that would link the ML1100 to a DH+ like the NET-ENI.

Give Prosoft a call. They interface everything to everything. I didn't see a DH+ to ETH module, but they might have something.

Micrologix and Devicenet

You might want to consider the A-B 1761-NET-DNI, if you have a ubiquitous DH+ network in your plant(s):

<quote>
The 1761-NET-DNI DeviceNet is a stand-alone, DIN rail or panel mounted, intelligent DF1 to DeviceNet protocol conversion device that allows DF1 full-duplex capable devices to communicate over DeviceNet.
Features Include:




The primary functions of the DNI are:

• Collect or receive data from the DF1 device connected to it's RS-232 port and forward the data to a connected master on DeviceNet
• Monitor output data received from the DeviceNet master and write the data to the DF1 device
• Allow DF1 devices to send and receive messages across DeviceNet

These capabilities allow I/O monitoring and control, peer-peer messaging between controllers, and messaging between PC's and controllers for program upload/download. The DNI is compatible with DF1 compliant devices such as Allen-Bradley controllers (e.g. MicroLogix, SLC 5/03, 5/04, 5/05, PLC-5), PC's, and many operator interface devices.

<endquote>

I was looking into doing something similar, but as I've got to build my network from scratch, I went Ethernet.

This item isn't cheap, unfortunately. Some of the other suggestions posted may be more economical.

If you haven't already purchased, I would also look at a Micrologix 1500 which can use the DeviceNet (1769-SDN) expansion card from the Compact Logix I/O lineup(we've used it thus in my plant). The info is all in the MicroLogix Selector Guide, here:

http://literature.rockwellautomation.com/idc/groups/literature/documents/sg/1761-sg001_-en-p.pdf

and here:

http://literature.rockwellautomation.com/idc/groups/literature/documents/sg/1769-sg002_-en-p.pdf

Adding some remote IO to the far plant's PLC-5 might be the cheaper way to go, depending on what it's already doing and how critical the processes are (one PLC problem shuts down the entire plant, etc.)


I'd be interested to hear what your final solution is.

L8R

> DH+ Long Gone?

We can but hope...