In need of A-B SLC-150 RS-422 comm protocol info


Thread Starter

Carlos E Ibarra

In order to change easily the values of some counters and timers in an Allen-Bradley SLC-150 I need to connect a PC to the SLC-150. I have a Pocket programmer (Allen-Bradley 1745-PT1) and a TCAT (Allen-Bradley 1745-TCAT) for changing the counter and timer values. I know that the SLC uses a serial RS-422 for communications and I assumme that it adheres to the standard voltage levels and handshake lines but I do not know the DIN connector pins assignment. In Allen-Bradley internet site I found a reference to its publication number 1745-2.11 titled SLC Programmable Controllers Comm. Protocol. This publication is dated as of 01 Jun 1988 and marked as obsolete. Nevertheless, I asked to the help service of Allen-Bradley who gently and quickly replied confirming that the publication is no longer available.
I intend to write some code that will change the values in accordance with a formula and, obviously, the knowledge of the protocol and pin assignment will help quite a lot.
Thanking in advance for any advice and help, sincerely:
Carlos E. Ibarra C.