AB PLC5/15 and serial device

  • Thread starter Pierre R. Hinse CET
  • Start date

Thread Starter

Pierre R. Hinse CET

I am looking for a way to connect a serial device, the customer does not want to change the PLC CPU.
Serial: RS232 belt scale 2400bd, ascii


Sudbury, Ontario, Canada
What about a DB module, this would allow a dos type of program to do anything with the data you would like.

Bob Peterson

You could add a 1771-DB basic module. Its somewhere around $1500 as I recall. Plus you will need the PBase software to program it. Another $500 or so. If you are clever and extra cheap, you could use a terminal emulator in place of the PBASE software but you might regret it in the end. BTW-PBASE runs only in DOS or a solid DOS window, and AFAIK will not run at all in NT or later variants.

By the time you screw around with all that, you might as well just go to a PLC5 with a built in serial port. Why spend > $2000 and end up with a bunch of obsolete stuff? Spend a few grand more and get something that is not obsolete. Might even be a good time to look at a switch to a different processor series.

Bob Peterson

If you've got a spare slot, you can use the 1771-DB module. It's a basic module with serial ports.

If you don't have a spare slot, you can either add a remote I/O rack with the 1771-DB module, or use a SLC-5/04. The SLC-5/04 has a serial port and DH+ communications (back to the PLC-5/15).

Some scales support Remote I/O as an option (i.e. Hardy 2151 series) so you might want to check this out.


Mark Wells
Runfactory Systems Inc.
1235 Bay Street, Suite 400
Toronto, Ontario, Canada M5R 3K4
Ph. 416-934-5038
Fax 416-352-5206

Yosef Feigenbaum

If you're just looking to read in simple ASCII strings you might want to look at the 1771-DA (ASCII module). A-B has got sample code and I wrote a program called DACONFIG that you might be able to find somewhere to make the configuration process easier. Once you get it going it's simple and rock solid.

A BASIC module (1771-DB) will also do the trick
but you'll have to check the cost.

If cost is not a problem, think about replacing
the CPU with a 5/20 which has an integral serial

You could use a 1771-DB BASIC module in a local or remote chassis; a fairly simple BASIC program would read and write strings. A new technology
alternative would be Prosoft's 1771MVI module, which is fundamentally a x386 DOS computer in a PLC-5 chassis module.

A Prosoft 1794-MVI with a 1794-ASB2 adapter would work on Remote I/O, as would I expect Prosoft's ProLinx Gateway product.

DataLink Technologies ( "www.dltech.net":http://www.dltech.net ) makes some specific-purpose DH+/ASCII and RIO/ASCII interfaces designed just for this purpose for use with PLC-5 Classic controllers, or Enhanced controllers that don't have the Channel 0 serial port available.