Cannot get working 5i25 + 7i76 + 8i20

I have LinuxCNC 2.5.2
5i25 upgraded to latest firmware 7i76_7i85s.bit (7i85s board is not connected yet, reserved for the future.)

I have working milling machine controlled by 5i25 + 7i76. 3 servo motors controlled by Step/Dir., 3 Home sensors and MPG pendant.

I have no luck to connect 8i20 to be my spindle motor.
8i20 is alive, I am able to configure it from my Windows via serial port.

The problem is when 8i20 is connected to 7i76 serial port no new devices related 8i20 appears in HAL configuration.

Serial port CONFIG="sserial_port_0=200xxxxx".

I verified serial RS422 wiring form 7i76 to 8i20 multiple times and I see with oscilloscope that there is no traffic on serial line.

How to get more info on how serial devices are detected?

Thanks.

Do you have the 8I20 jumpered for operate mode?

It will not be found in setup mode.
that is W6 must be in the up position

>Do you have the 8I20 jumpered for operate mode?

Yes W6 in Operate mode.

OK so other things needed for 8I20 to start are

1. Proper cable (see colors in 7I76 manual page 11: RS-422 interface)
2. Motor power (>40V) must be present for 8I20 to start
3. 8I20 drive enable powered

if these are right and you still have trouble can you start linuxcnc and attach you dmesg here? that is:

sudo dmesg -c
launch linuxcnc
exit linuxcnc
dmesg > log.txt

and post log.txt here

LinuxCNC is upgraded from 2.5.2 to 2.5.3

>1. Proper cable (see colors in 7I76 manual page 11: RS-422 interface)
Just verified one more time, wiring is properly done.

>2. Motor power (>40V) must be present for 8I20 to start
High voltage is applied, 161 volts (120V line operated supply).
It raised one more problem in Operate mode braking is on all the time. In Setup Mode bake is off.
To avoid damage I added to the brake circuit current limiting resistor.

BRAKEONV and BRAKEOFFV are set like this:

RPD FAULT
Data 65534

RPD STATUS
Data 0

RPD NVMAXCURRENT
Data 200

RPD NVBRAKEONV
Data 2000

RPD NVBRAKEOFFV
Data 1800


>3. 8I20 drive enable powered
Yes connected directly to 12 volts.

Still no communication:
>if these are right and you still have trouble can you start linuxcnc and attach you dmesg here? that is:

The fact that the brake is on all the time does seem to indicate
a faulty 8I20 or at least one with scrambled EEPROM settings

I am a little puzzled by your saying the you needed a current limit resistor for the brake circuit, since the brake circuit always needs a brake resistor

I would request an RMA from MESA to return/evaluate and repair/replace
the 8I20

PCW wrote:

I am a little puzzled by your saying the you needed a current limit resistor for the brake circuit, since the brake circuit always needs a brake resistor

A normal brake resistor is 15 Om and gives 10 amperes of current if brake is on. It is not a problem if it is for short period of time. When it is on all the time it gets overheated very fast and could burn. For test purposes I increased it to 500 Om to limit the current and have more time to test communication.

PCW wrote:

The fact that the brake is on all the time does seem to indicate
a faulty 8I20 or at least one with scrambled EEPROM settings

I would request an RMA from MESA to return/evaluate and repair/replace
the 8I20

Is there a way to reset EEPROM settings?
May be Reflash firmware?

May be it might give some ideas, this board was replaced on recall.
In November last year you ordered the Mesa 8I20-ROHS from our company. Your PO# was PO #221112Y.

Unfortunately MESA had an assembly error which resulted in this part not being fit for use and so they are issuing a product recall.

You have an automatic RMA# for return of the product, and Mesa will replace it for you immediately.

I would still return it
Having the brake stuck on is a serious fault,
and one that should be analysed

I noticed when looking up the brakeonv and brakeoffv
that the 8I20 manual on the website is obsolete and full of errors
So you may just have some EEPROM variables set wrong
Main thing is that all the voltages are in 10 mv units not
100 mv as shown in the manual

I have put an up-to-date manual on the website:

www.mesanet.com/pdf/motion/8i20man.pdf