1769-HSC 1 Encoder, 1 Discrete?

Thought I would post this in its own thread:

I have successfully integrated a TTL signal encoder into the 1769-HSC, and am getting counts in the register. That's the good part.

How can I use one of the other counters for a proximity sensor (spindle RPM)? All of the HSC card setups I have tried yielded card faults.

If it helps, the current setup I am using is 1 counter in Encoder X1 mode. The AB manual doesn't specify how to "mix & match" encoder and discrete inputs.

Ideas?

Please give a litle more info.
TTL is usually 5VDC
Does the encoder have a Z pulse - Assuming it is the same shaft.
the TTL may also be NPN - I do not know
I am not that familure with the AB HSC setup - I understand it to be a 4 Channel card - you would need to be using one of the other channels and set it up as a single pulse counter.

I will clarify that the encoder is not on the same axis or even related to the spindle for which I want to read the RPM - I am simply trying to make better use of the current PLC resources by doubling the functionality of the HSC setup.

The TTL encoder is hooked up to the HSC as follows:

A0+/A0-
B0+/B0-
Z0+/Z0-
Power - +/- 5VDC

The HSC is currently set for one counter with that counter set as type "Encoder X 1".

This setup works great - I have no trouble getting the proper information from the encoder.

I would like to use another counter in the same card to read spindle RPM on the machine from a proximity sensor. I have not been able to figure out the proper configuration of the card which allows the encoder on one counter, and a discrete input on one of the others. I ASSUME that the encoder uses two out of the four counter spaces, so I should have room for two discrete counters remaining.

All configuration attempts thus far have yielded card faults, so I have returned to operating with just one counter setup for the encoder.

iant said:

The information is in this PDF
1769_um006__en_p.pdf
too large to Post
look at the counter setup around 81
the note suggests that you can not change the card settings while it is enabled (porgram is running)
the X1 setting is for Quadrature (A-B Pulse Encoder)
you can not use this setting for a straight counter

Click to expand...

Okay - even though I had looked through that .pdf several times, I missed the part where it gave examples of how to use a quadrature encoder with an incrementing encoder or sensor. Page 18 gives a summary of available counter configurations. I will try the appropriate configuration once I am onsite with the machine this afternoon and report my findings here.

On a side note, I discovered that inhibiting and re-enabling the HSC card is sometimes necessary to clear a card fault (if the program is running).

Thanks!