AB PLC history lesson

[autocontrolit 0]

Silly trivia type question. I came into the plc scene and was introduced to PLC 5 class of PLC. Did Allen Bradley make a PLC put into production use before the PLC 2? I think I have the first PLC 2/30 sold by Allen Bradley, and put into production if my source is correct. It does not look like the PLC 2's I have seen before. Almost all of the PLC 2's I see have a "screen" stlye venting in the outer metal case this one has a stamped metal case with slots for venting.

[TimWilborne 108]

Interesting, can you show us a picture? plcdev.com has a pretty good time line of the history of PLCs http://www.plcdev.com/plc_timeline

[newpageboba 7]

You are making me show my age. Allen Bradley had a Bulletin 1774 product called PLC It used 1778 I/O at first and then the 1771 I/O came out. It talked to the I/O via an I/O distribution panel and individual serial cables to each Rack No. The chassis used a 1778-AR module for 1778 I/O & a 1771-AR for 1771 I/O They also had PLC2/20, PLC 3 & 3/10 and a PLC4

[autocontrolit 0]

I will try to upload a pic tonight.