Mesa 5i25+7i77 plug-n-go configuration

I changed the polarity in the ".ini", no luck. My next plan is to test the drive independent of the 7i77, maybe I have the drive (BE25A20C) configured wrong.
I attached my hal and ini, its very possible I am making a basic error on the software side also.

When I soft enable the be25ac20 drive goes green indicating that it has been enabled.

The 7i77 TB5 aout0 reads 1.43 volts?
The 7i77 TB5 gnd reads 0

This appears to be enough for the motor driver to start the servo, because it runs away only to be stopped with "joint following error"

Why would the auot0 be giving me 1.43 if no motion was commanded?

If AOUT0 (TB5 pin 4 = fourth from bottom measured relative to pin 3) is 1.43V when disabled
(linuxcnc is not running) and you have disconnected all connections to
external hardware, this indicates a bad 7I77.

if it only happens when you enable linuxcnc, its most likely feedback related
and you will have to trace the PID inputs and output with halmeter to figure out what
is going on (you may also have to widen the ferror limits so see whats happening)

The other thing to try is the open loop test in pncconf and seen if you can make the
motors run each direction (beware that this may runaway)

I am pretty green at this,

When we say feedback, I associate that with the encoder.
The encoder apears to function, I see the icon move when I spin encoder by hand.

Since it is the 7i77 that is supplying signal to the driver, (1.43) what other "feedbacks" could I be messing up? Have I missed an entire wire group?

The feedback to the driver, I pulled from the encoder bank on 7i77

All my signal grounds go to 7i77 field ground.

Is thier a list of PID inputs & outputs I should start checking. I am not sure how many thier are total?

First: did you measure the voltage between TB5 pin 4 (AOUT0 ) and TB5 pin 3 (ANALOG GND) with linuxcnc not running?
and all TB5 connections disconnected? If this is not very close to 0V, (and 7I77 5V is OK) there is a hardware problem with the 7I77

Second: Field I/O ground should normally have NO connections to the analog I/O section of the 7I77.

analog wiring is all to TB5

AOUTN --> DRIVE AIN+
GNDN --> DRIVE AIN- or DRIVE ANALOG GND

GNDN is next to AOUTN on TB5

I have attached a illustration of how I wired it.
It sounds like I should have the #11 signal ground on the TB5 gnd, the same location i have the #5(-ref in)?

Yes the drives signal gnd can be returned to TB5 pin 3 (analog gnd) with a separate wire
also, there should be no explicit connection of any field I/O pin to the analog signals so
the field power gnd connection should be removed

I checked the voltage at TB5 from pin 3 to pin 4. (with all TB5 wires disconnected)

I get 1.1volt with Linux off.

I have the 5v supplied at Tb1 from the 5i25, that is currently showing 4.8.

My interpretation of your statement is that the 1.1volt reading indicates a bad board? because we would expect to get zero at this location.

I checked the 3&4 pins of other axis and I get a similar reading approx. 1.1volts

Is it time to order a new board?


fixing the signal ground to pin 3 instead of field ground had no effect

I would request a RMA number from Mesa for the 7I77 and when you get the number,
send the 7I77 back to Mesa for evaluation, repair and possible replacement

33zy: we have received and repaired and returned your 7I77
Since I dont have any contact information I will post this here

The problem found was a bad 74ACT04, This likely indicates
that the7I77s 5V supply was wrong (Either backwards or >7V)
So please check your power supplies before re-installing the 7I77