Allen-Bradley Push Button Switch Application


Thread Starter

Enrico Diano

Hi, I'm considering to use Allen Bradley switch part number 800T-16JBH5KB7J and I have a question. First of all, this is a 120VAC 3-position switch with a built-in transformer to power the LED. The left position is OFF, the middle position is ON, and the right position is a spring return ON. I want to use this as a main power switch (OFF or ON) but I also want to use the spring return position to send a RESET signal to my PLC. Can I wire a DC voltage (suitable for a PLC input) through the third (RESET) position on the switch? (Or am I limited to using if for only AC signals???) By the way, the PLC is an Allen Bradley Micrologix 1200. Thanks, Enrico Diano Manufacturing Engineering Celestica Inc. Toronto, Canada

Steve Myres, PE

I'm not familiar with this specific part, but in my experience with the A-B 800T line, all output contacts from the device are fully isolated from each other and from the input to the lamp, if any. So you should be able to do what you want with no problem, as long as there is a contact block available. If not, one can easily be added to an existing switch. Steve

Alfonso Padilla

Hi Enrico, You shouln't have trouble in doing this, since AB's switches provide separate contact blocks for each position. Therefore you can wire your AC circuit to the block(s) actuated when OFF and ON, whereas the PLC DC reset circuit can be connected to the momentarily actuated block. The polarity depends if the input is sinking or sourcing-type. The transformer-powered LED may be connected to the AC circuit to be lit when ON (see example on the attachment). I am just upset because I couldn't find the 800T-16JBH5KB7J switch in my AB catalog. I found the 800T16JBL5KB7J instead. One question: what does the H in the middle mean ? Alfonso Padilla QPS Control & Automation Mexico [email protected]

Jeffrey W. Eggenberger

You should have no problem using another set of contacts on the switch for dc as long as you do not exceed the specs of the switch. Jeffrey W. Eggenberger Electrician: Industrial, Commercial, and Residential
I am not familiar with that particular part number, but if it is a dry contact, yes you can. You must however make certain that it is isolated from the 120 volt system. Hugh Browne Project Engineer