DH+ to Ethernet

Hello,
I’m looking for a device that can convert a DH+ network to Ethernet, and then convert it back to DH+ - in order to extend a DH+ network.

In a nutshell, I have a system that has a PLC that is talking to a PC. We want to move the PC to a data center that is about 5000' from the current location. We are trying to avoid modifying the PLC and PC hardware/software. Does anyone know of a device that can convert DH+ to Ethernet, then covert it back to DH+ - - - and be transparent to the DH+ network devices?

Thanks for your help!
James

You should be able to use (2) 1761-NET-ENI adapters.

I wouldn't recommend the NET-ENI, this puts your processor on ethernet, but has very limited connections, and does not seem to handle lots of information well.

As far as anything being transparent, I do not know of anything. You could set up an ethernet bridge with a control logix rack, a 1756-ENBT, and a 1756-DHRIO card. You would then put your PC on ethernet to the ethernet card in the control logix rack, and leave the PLC on DH+. You would then change your routing in the PC from the DH+ driver to the ethernet, to the ethernet card thru the backplane to the PLC. Therefore all you should have to change is in RSLinx, or what ever OPC server you are using, all your tag names should remain the same in the PC and PLC with no tricky messaging or anything.

If you have fiber single mode between the locations, you could use DH+/Fiber transceivers. AB made a module in the past, but I believe it has been discontinued at this time.

Funny thing is that we still have a dozen of them in service.

FYI: DH+ can span up to 10,000', but you would have to buy and install 5000' of "blue hose" to connect the sites:
http://www.plctalk.net/qanda/showthread.php?t=49836

We have some of these too:
http://www.westermo.com/Resource.ph...bre-optics/fieldbus-devices/allen-bradley.htx

But we are not using them any more.

windows has a built in remote desktop if you could leave the pc where its at and add a pc at the data center this could work just depends what you want to do at the new location. just a thought

hmm good idea tho bce PC are getting cheap.. and some of the hardware mentioned is just as much

heck if it's going to a "data center" they should have a pc there anyways.

yes robo i use this on remote sites over the www to control sites using a local hmi have remote ptz,s so can see whats going on its cheap and works

Welcome to the Forum, PinJim !

The exact PLC model, and the hardware and software running on the PC, will help refine the suggestions you get.

With just those three details, "PLC, PC, DH+", the system could be anything from a PLC-3 and ControlView to an SLC-5/04 with SST-5136 and Wonderware. The best solutions for each of those may be different.

In my opinion, the ideal approach would be to change the PC so that it's communicating on Ethernet, then provide an Ethernet-to-DH+ interface. That gives you a number of options, including RSLinx Gateway, ControlLogix 1756-series network modules, and devices from QTS and DataLink.

I don't think there is a way to do what you precisely state: to connect PC -> DH+ -> Ethernet -> DH+ -> PLC, without changing any configurations.

The closest thing to what you state would be to use a 1756-ENBT and 1756-DHRIO at each end of the Ethernet network, but that would require that the PC and software support Remote DH+ Addressing, and that you change the PC configuration to use a Remote Address. This is both the most expensive and slowest method.

No, wait, I thought of a slower and more expensive way.

PC-> DH+ -> 1770-KF2 -> RS232/Ethernet -> Ethernet -> Ethernet/RS232 -> 1770-KF2 -> DH+ -> PLC.

The 1770-KF2 could be a DataLink DL3500, since the KF2 hasn't been in production for decades.

The RS-232/Ethernet could be a Lantronix or Moxa or Digi device. It doesn't need the Industrial application protocols, just a device-to-device "nailed-up" mode.

The PC would address a local DH+ address and the KF2 would provide a back-to-back link to the other DH+ network.

Ought to cost about $8000 to start and will be slow a molasses in January.

But it will satisfy your originally posted requirement of not modifying the PLC or PC.

Lol

Byte the bullet and put Ethernet/IP in the PLC. It will make life a lot easier for you in the long and short run