1770 KF3 Replacement

I'm helping a client of mine after a big lightning blast to their water treatment plant. they have a Fix32 node communicating to a SLC 5/03. The comm path is 232 serial to a KF3 module and then RS 485 to the PLC. I believe the KF3 took a big hit and I need a replacement. I'd like to use a device sold by B&B Electronics that is orders of magnitude less expensive. I don't know however if it will work. The KF3 module has a node address that is settable, but I don't see that capability with the B&B device (232ABRJ45). There are no other devices on the network so Point to point would work as long as the Fix32 device driver will work.

Any experience in such matters??
thanks

Have a look here

http://www.ab.com/manuals/cn/17706518.pdf

The KF3 is a DH485 interface. I'm not sure a RS485 converter will
work. But I may be wrong never tried it.

They Just called me and decided to fork out the $$ for an AB KF3, insurance will cover it.
Now we may never know....

The 1770-KF3 and its cousin the 1747-KE are protocol converters, not just signal converters. They actually convert from the full-duplex asynchronous DF1 protocol to the token-passing, time-dependent DH-485 protocol. They also happen to convert from RS-232 signalling to RS-485 3-wire signalling along the way.

A regular old RS-232 to RS-485 converter will NOT do what the KF3 does.

A good alternative that does functionally replace the 1770-KF3 at a much lower cost is the DL-3500 from DataLink.

http://www.protocolconverter.com/products/DL3500.htm

DataLink seems to have some handy products, thanks. I guess I'd have to call them for a qoute?

If FIX can communicate directly via DH485 protocol, then a simple RS232/RS485 converter will be sufficient.

Yeah I see what you mean, I'd have to get into the fix node to see if the driver actually has a DH485 address for the data-sets. I can't remember.

Another option maybe a DR-IAP device server from Lantronix. These are available with some automation protocols including DF1 and Modbus. They communicate out from the untis in either RS232 or RS485.

www.lantronix.com

One more time, with emphasis:

RS-485 is NOT THE SAME as DH-485.

Data Highway 485 is a PROTOCOL. RS-485 is just an electrical signalling standard.

None of the general-purpose Ethernet/serial gateways on the market support DH-485 protocol, including the "industrial protocol" ones from Lantronix.

And while I'm having my fit... a generic RS-232 to RS-485 converter will usually not work with Data Highway 485.

DH-485 uses "Two Wire" RS-485 signalling, with three wires; Data+, Data-, and Signal Common. That signal common wire MUST be part of the network and it's isolated from the devices on the network by those "AIC" isolators.

RS-232 has at a minimum the Tx, Rx, and Signal Common wires. When you convert to RS-485, which uses the same wires for Transmit as for Receive, you have to ask yourself "when do I transmit and when do I receive? ".

With many RS-232/485 converters, the answer is "your protocol has to determine that". With some, the answer is "we use automatic data transmit detection".

But when you're using DH-485, the answer is "The RTS and DTE handshaking lines control transmission and receiving".

That's why the 1747-PIC device is not a trivial 232/485 converter, and why B&B Electronics offers a special "1747-PIC equivalent" as well as their standard RS-232/485 converter products.

Would the easiest be to connect from the FIX PC with a 1761-NET-AIC ?