Welcome! Here are the website rules, as well as some tips for using this forum.
Series 90/135Ω info needed
So our service guys are stuck on an old church with Series 90 controls, & it looks like I'm going to have to help them out. Does anyone have some literature on them? I understand the basic concept (Wheatstone bridge) & I'm reading all the old ModIV etc. manuals from Honeywell as well as The Engineering Manual of Automatic Control
, but I'm hoping for a jump-start on knowing all the tricks & Clever Things the Old Guys used to do.