sequenced go-no-go gage

Looking for a solution, we are building a fixture to test an injection molded part with 4 metal inserts. the fixure is built, just having problems with the program. Using micrologix 1000 plc. We need to test for continuity in each of the 4 inserts, but we cant have continuity between two different inserts. All we are doing is energizing one relay output at a time to activate the corresponding input and then unlatching it. I'm unsure as to how I can save that signal after unlatching that output and moving on to enegize the next output to recieve the next signal. I'm very unfamiliar with this new RSlogix software. I thought of energizing an internal relay for each signal, and then using all 4 relays to signal a green light or red light for bad part. What are the internal relay designations in this software, or is there a better way to go about it? How would I reset those relays if used?
Thanks for the time
Chris

Something like this?

Thanks, that is just what we were looking for, it worked great.
Thanks for your time.
Chris

I'm not sure on your process, but you may want a short condition, to fault out the test. Most likely if two pins are barely shorted, one of the tests will show bad, however it only takes one ladder scan to show a good part in the example above... You may miss an intermittent contact.

Brijm said:

I'm not sure on your process, but you may want a short condition, to fault out the test. Most likely if two pins are barely shorted, one of the tests will show bad, however it only takes one ladder scan to show a good part in the example above... You may miss an intermittent contact.

Click to expand...

Good point! You may also wish to have the test exercise the contact integrity at the rated load. (See Ohm's Law to set up the load circuit voltage, current, and resistance values.)

I wouldn't run the test too hastily or you will indeed miss the intermitant problems. Run the test for whatever time is available (1/2 second?) or run multiple tests while in the test station.

Chris-trmaint said:

Thanks, that is just what we were looking for, it worked great.
Thanks for your time.
Chris

Click to expand...

IMO, Alaric's example could use some more control reliability with respect to when the rungs for the OTLs are true. Placing a normally open contact (XIC) of the output in series with the expected XIC input would assure that the OTL instruction is energized only when its supposed to.

Example: if the timer value is 2, O:0/2 is on. If you are expecting only I:0/2 to come on and only I:0/3 comes on instead, the rung OTL B3/3 would be energized and give a false positive, a big no-no in the gaging world. To add reliability:

In rung 6 insert -| |- O:0/0 at the beginning of the rung.

In rung 7 insert -| |- O:0/01 at the beginning of the rung

In rung 8 insert -| |- O:0/02 at the beginning of the rung

In rung 9 insert -| |- O:0/03 at the beginning of the rung

That will coordinate the input response with the output.