Sector 7 OMS Servo motor installation


Eric Dufresne
Sector 7
Started September 10, 2002
(www.xray.aps.anl.gov/~dufresne/Manuals/servos/)



Sector 7 OMS-8s servo motor EPICS installation and related information.

Introduction.

On 7ID in early 1999, we started using small MicroMo motors controlled by an OMS
VME58-8s servo card supported by the motor record in EPICS. The APS Beamline 
Controls and Data Acquisition group designed a modified motor transition module
for the task. The links below describe the EPICS set up currently used on 7ID
to drive three slit units with small MicroMo servo motors. Similar installations
exist also at PNC and IMM-CAT. The work at Sector 7 was done by Ernest
Williams, Harold Gibson, Debra Hilborn, Tim Nurushev, Steve Dierker, Eric
Dufresne, Ron Sluiter (APS), Kurt Geotze (APS).

09/29/05 Please make sure that you use the correct version of the BC-003
paddle board. Only BC-003 rev. 2 will work with servo motors. Thanks
to Julie Cross for pointing this out.
See BC-003 harware manual on BCDA site.

Motor type used at Sector 7.

On 7ID we use MicromoMotors for driving slits.  We can drive also
the new ThorLabs Z6 actuators.  The Micromo Motors are: 
1016M012GK380+10/1K1024:1+HEM1016M10
This type of motor is the only type tried on 7ID.

The Motor pin out: 
We first replaced the original MicroMo 10 pin connector with DB-9 male ones.
The cable 1-6 on the 6 motor ribbon cable were connected to pin 1-3 and 6-8 of
a DB-9. The wiring diagram below is for a 6 wire D9 to D25 adapter cable used to
connect the motor to the BCDA transition module DB-25 female connectors.

Micromo ribbon cable #      Motor DB-9 Pin      DB25 pin on transition module
 1 Motor (+)                      1                         3
 3 Encoder chan. A                2                         7
 5 -VDC (ground)                  3                        24
 2 +VDC (encoder power)           6                        14
 4 Encoder chan. B                7                         8
 6 Motor (-)                      8                        11

Please make sure that you use the correct version of the BC-003 paddle board.
Only BC-003 rev. 2 will work with servo motors. Thanks to Julie Cross for
pointing this out! The above wiring was also double checked on 9/29/05.

ThorLabs Z6 actuators operation notes:
The new servo screws from ThorLabs are another example of micrometer one
can use with the OMS servo card. These micrometer replacement actuators
(MRA) are also equipped with limit switches. One problem I've noticed is
that if one reaches a hard limit, the motor current is disabled. If one
doesn't realize that this just happened, one may loose motor position. 
Also, when the servo reaches its upper limit, the lead screw is out
about 17 mm from the body of the actuator. See below  for the manual and my
initial EPICS record settings:



Thorlabs new stages Z825B have a 1 mm pitch screw with a higher encoder
count (256/motor rev) and a different gear 67:1.

Links to the APS Beamline Controls and Data Acquisition (BCDA)
group for their servo version of BC-005.

Kurt Goetze from BCDA designed the servo version of the APS transition module
for the OMS VME 58-8S cards. Below are links to the BCDA Home page for
documentation on the unit. For more information,  please contact Kurt Goetze
([email protected]) or Peter Fuesz ([email protected]).

EPICS screens used at Sector 7 and motor record links.

For the servo drivers, several additional fields are initialized in the motor 
record, thus modifications of a typical EPICS motor screen were done to include
the P,I,D coefficient and the motor power on/off switch. Below are links to all
these screens and useful EPICS info on the set up.

EPICS record startup, magic tricks, bugs from 7ID experience.

To set up one motor: 
1-Make sure the transition module is powered. The red and green lights on the 
  module should be on.
2-Connect the motor to the transition module cable.
3-Refresh the motor record by typing the ENTER key in the P,I,D Coefficient
4-Enable the motor power
5-Tweak the motor and make sure the encoder are updating during the tweak.
6-If not, restart at point 3.
7-Make sure thet motor is not oscillating if so disable the motor and restart
  at point 3 until the motor stops oscillating.

Note when the VME crate reboot, it is possible that if the autosettings.req
file are not setup right, the motor will return in a disabled mode.
It is important then to enable the motor power again. Please make sure to 
include all the PID (PCOF,ICOF,DCOF) fields and motor enable buttons in the
autosettings.req file.

The main bug is oscillating motors the first time it is set up. It is typically
easy to fix. This often occurs if the transition module power supply was turned
off with the VME power cycled.

Note that the OMS servo board are more sensitive to damage than the stepper
versions. We've damaged a few channels typically due to improper wiring, i.e. 
putting 12 V on the encoder channels so care is needed.

We never tuned our parameters so I don't have much experience with tuning the
OMS servo loop. Defaults parameters worked for the Micromo motors mentioned 
above and displayed on the screen.
Back to my xray internal homepage (retour vers ma page maison).
Récemment modifié le 16 octobre 2020
par Eric Dufresne,
Bldg 432 Rm D007 630-252-0274