Connecting an MPG to 7i77

Hi folks.

I'm wondering if it is possible to set the 7i77 board to software mode 0 and then use any of the inputs to connect to an MPG with 24V A/B-pulses.

The reason I ask is because I don't want to tie up four of the inputs (inputs 0-3) as analog inputs by using software mode 3, because I don't need any analog inputs on this project.

-Will a "normal" input have sufficient response-time/sampling-rate to read MPG-signals?
-Are there any significant benefits of setting the board to software mode 3 and using inputs 16-19 for this or is the only reason for this to be able to use 5V signals?

Thanks in advance.

Best Regards:
Frode H.

You don't "lose" any 7I77 inputs in any mode.

That is, even in mode 3, the 32 digital inputs function
normally.

When the MPGs are enabled the input threshold
is set to 2.5V (but only for the MPG count function)
The digital inputs 16..19 function normally with ~ 50%
of field voltage thresholds.

Likewise, the analog inputs do not interfere in any way
with the normal digital input function of inputs 0..3

The advantage of the MPG pins vs field inputs is that they are sampled at
about 50 KHz rather than at the servo thread rate (usually 1 KHz)
so you cannot easily spin a MPG dial fast enough to lose counts
with the MPG inputs, but it's easy to do with field inputs sampled at 1 KHz

Hi PCW.

Thank you for your fast reply to my post.

In software mode 3:
-Can I still use 24V as the field voltage for the board so that the rest of the inputs (except inputs 16-19) can be used for 24V input signals?
-Can I use the analog inputs (inputs 0-3) as normal 24V digital inputs?

One more thing:
-Can I connect a 24V MPG to the inputs on a 7i70 board?
-Will these inputs have sufficient response-time/sampling-rate to process MPG-signals?

Best Regards:
Frode H.

Hi again.

I just noticed that you edited your first post. Now I think I understand the concept.

Thank you so much PCW.

Best Regards:
Frode H.