( Solved ) Mesa 7i76 encoder problem

PCW wrote:

It could also be a 5I25 or cable problem

I have re seated the 5i25 and the cable. Would re flashing the card help. or is there anyway to test.

I do have the 7i76e could the 7i76 be plugged into that to test with the correct firmware.

I also have a 7i96

If the card was working, reflashing will not help.
Reflashing basically never helps unless you need to change
the firmware or replace corrupted firmware, but corrupted
firmware on a 5i25 will result in loading the fallback config
which has no encoders or stepgens so will be obvious.

Can you read the input-a pin state when the
7I76 is not connected vs connected (with encoder unplugged)?
That will verify if the 5I25 is OK

It should read high if the 7I76 is unconnected and
low if the 7I76 is connected if the 7I76 is jumpered for
TTL mode and the encoder is unplugged

To load the driver and read pins without the 7I76 you can do this:

halrun
halcmd: loadrt hostmot2
halcmd: loadrt hm2_pci config=" "
halcmd: loadrt threads name1=servo-thead
halcmd: start
halcmd: addf hm2_5i25.0.read servo-thread
halcmd: getp hm2_5i25.0.encoder.00.input-a

PCW wrote:

Can you read the input-a pin state when the
7I76 is not connected vs connected (with encoder unplugged)?
That will verify if the 5I25 is OK

It should read high if the 7I76 is unconnected and
low if the 7I76 is connected if the 7I76 is jumpered for
TTL mode and the encoder is unplugged

To load the driver and read pins without the 7I76 you can do this:

halrun
halcmd: loadrt hostmot2
halcmd: loadrt hm2_pci config=" "
halcmd: loadrt threads name1=servo-thead
halcmd: start
halcmd: addf hm2_5i25.0.read servo-thread
halcmd: getp hm2_5i25.0.encoder.00.input-a

Ok With the encoder unplugged from the 7i76

7I76 is unconnected
A shows true
B shows true

Rebooted then:-

7I76 is connected
A shows true
B shows true

Does this mean the 5i25 is faulty. I have not changed the PP cable but is is a good quality one and short

I would guess that the 5I25 is OK but both A and B should be low
when the 7I76 is connected (and the encoder is unconnected)
Are you sure the 7I76 is jumpered for TTL mode?

PCW wrote:

I would guess that the 5I25 is OK but both A and B should be low
when the 7I76 is connected (and the encoder is unconnected)
Are you sure the 7I76 is jumpered for TTL mode?

I don't understand it this has be running for a few years. I have just checked and you are of course correct, they were wrong.

They are now set as single ended now it is working again.

Could it have worked before ? !!

Many thanks for the patience.

It can sort-of work with single ended signals and differential inputs
because you can develop a 100 mv or so differential input with single
ended signal because of the way the termination works.

PCW wrote:

It can sort-of work with single ended signals and differential inputs
because you can develop a 100 mv or so differential input with single
ended signal because of the way the termination works.

Thanks that explains a lot.

It must have been just on cusp of it working.