AM882 Alarm Circuit

[Neale]

I'm sure that there is something wrong with that Leadshine circuit. The "R" for the alarm circuit should not be 0 for the 5V case. That would short out the 5V supply when the alarm went off, followed by the demise of the opto-isolator microseconds later. What you should use as a pull-up will depend on what is in the block on the left. Personally, I would put the 24V relay where R sits, connect alarm outputs in parallel, and corresponding terminals to 24V ground, but it's 6 of one and half-a-dozen of the other and the other suggestions would work fine.

[irving2008]

Not sure why you want the relay, its one more thing to go wrong. The FAULT input on a PMDX is already pulled up internally so just wire all ALM+ to Fault and ALM- to GND on J13. The ALM outputs are already opto-isolated so the additional isolation of the relay is superfluous.

I'm sure that there is something wrong with that Leadshine circuit. The "R" for the alarm circuit should not be 0 for the 5V case. That would short out the 5V supply when the alarm went off, followed by the demise of the opto-isolator microseconds later. What you should use as a pull-up will depend on what is in the block on the left. Personally, I would put the 24V relay where R sits, connect alarm outputs in parallel, and corresponding terminals to 24V ground, but it's 6 of one and half-a-dozen of the other and the other suggestions would work fine.

You're right, and Leadshine have changed the manual as in the other thread referenced the Leadshine circuit shown there (and copied here) R only applies to the opto-inputs not the output... its not labelled 'R', though I agree its potentially misleading.