Getting Encoder Reading with 7i96s + 7i85s

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18 Mar 2024 00:34 #296163 by ltcnc
I'm working through PnCConf for a new build but I can't seem to get any kind of encoder readings when I test my stepper motors. I'm using a 7i96s + 7i85s card. The encoders are technically differential and have QAX, QAX/, QBX, and QBX/ signals. (No index pulse.) I was reading odd pulse voltages (only 1-2V with respect to ground) when I tried using the differential pulse, so now I'm running them as TTL (disconnected QAX/ and QBX/ signals) and changed the jumpers on the 7i85s to the "up" position. This gives 0 and 5 volt readings on both QAX and QBX when I rotate the encoder, but I'm still just seeing encoder readings of zero on the hal probe when I test the motor. 

I'm pretty sure I'm using the correct firmware (downloaded from mesa). I flashed the 7i96s_7i85sd.bin, which PnCConf seems to be discovering correctly (at least, I have the option to choose the encoders on the P1 tab). I'm also pretty sure everything is wired correctly, I'm testing encoder 0 on the TB3 connector of the 7i85s and have double checked the wiring multiple times. Also, I can get the 7i96s to drive the stepper, but again only seeing 0's on the encoder reading.

Here's my rough HAL file (I haven't really tuned anything in, mostly trying to get this issued solved first):
# Generated by PNCconf at Sun Mar 17 19:57:24 2024
# Using LinuxCNC version:  Master (2.9)
# If you make changes to this file, they will be
# overwritten when you run PNCconf again

loadrt [KINS]KINEMATICS
loadrt [EMCMOT]EMCMOT servo_period_nsec=[EMCMOT]SERVO_PERIOD num_joints=[KINS]JOINTS
loadrt hostmot2
loadrt hm2_eth board_ip="10.10.10.10" config="num_encoders=6 num_pwmgens=1 num_stepgens=9 sserial_port_0=00xxxxxx" 
setp    hm2_7i96s.0.pwmgen.pwm_frequency 20000
setp    hm2_7i96s.0.pwmgen.pdm_frequency 6000000
setp    hm2_7i96s.0.watchdog.timeout_ns 5000000
loadrt pid names=pid.x,pid.y,pid.z,pid.s

addf hm2_7i96s.0.read          servo-thread
addf motion-command-handler   servo-thread
addf motion-controller        servo-thread
addf pid.x.do-pid-calcs       servo-thread
addf pid.y.do-pid-calcs       servo-thread
addf pid.z.do-pid-calcs       servo-thread
addf pid.s.do-pid-calcs       servo-thread
addf hm2_7i96s.0.write         servo-thread
setp hm2_7i96s.0.dpll.01.timer-us -50
setp hm2_7i96s.0.stepgen.timer-number 1

# external output signals


# external input signals


#*******************
#  AXIS X JOINT 0
#*******************

setp   pid.x.Pgain     [JOINT_0]P
setp   pid.x.Igain     [JOINT_0]I
setp   pid.x.Dgain     [JOINT_0]D
setp   pid.x.bias      [JOINT_0]BIAS
setp   pid.x.FF0       [JOINT_0]FF0
setp   pid.x.FF1       [JOINT_0]FF1
setp   pid.x.FF2       [JOINT_0]FF2
setp   pid.x.deadband  [JOINT_0]DEADBAND
setp   pid.x.maxoutput [JOINT_0]MAX_OUTPUT
setp   pid.x.error-previous-target true
# This setting is to limit bogus stepgen
# velocity corrections caused by position
# feedback sample time jitter.
setp   pid.x.maxerror 0.012700

net x-index-enable  =>  pid.x.index-enable
net x-enable        =>  pid.x.enable
net x-pos-cmd       =>  pid.x.command
net x-pos-fb        =>  pid.x.feedback
net x-output        <=  pid.x.output

# Step Gen signals/setup

setp   hm2_7i96s.0.stepgen.00.dirsetup        [JOINT_0]DIRSETUP
setp   hm2_7i96s.0.stepgen.00.dirhold         [JOINT_0]DIRHOLD
setp   hm2_7i96s.0.stepgen.00.steplen         [JOINT_0]STEPLEN
setp   hm2_7i96s.0.stepgen.00.stepspace       [JOINT_0]STEPSPACE
setp   hm2_7i96s.0.stepgen.00.position-scale  [JOINT_0]STEP_SCALE
setp   hm2_7i96s.0.stepgen.00.step_type        0
setp   hm2_7i96s.0.stepgen.00.control-type     1
setp   hm2_7i96s.0.stepgen.00.maxaccel         [JOINT_0]STEPGEN_MAXACCEL
setp   hm2_7i96s.0.stepgen.00.maxvel           [JOINT_0]STEPGEN_MAXVEL

# ---closedloop stepper signals---

net x-pos-cmd    <= joint.0.motor-pos-cmd
net x-vel-cmd    <= joint.0.vel-cmd
net x-output     => hm2_7i96s.0.stepgen.00.velocity-cmd
net x-pos-fb     <= hm2_7i96s.0.stepgen.00.position-fb
net x-pos-fb     => joint.0.motor-pos-fb
net x-enable     <= joint.0.amp-enable-out
net x-enable     => hm2_7i96s.0.stepgen.00.enable

# ---Encoder feedback signals/setup---

setp    hm2_7i96s.0.encoder.00.counter-mode 0
setp    hm2_7i96s.0.encoder.00.filter 1
setp    hm2_7i96s.0.encoder.00.index-invert 0
setp    hm2_7i96s.0.encoder.00.index-mask 0
setp    hm2_7i96s.0.encoder.00.index-mask-invert 0
setp    hm2_7i96s.0.encoder.00.scale  [JOINT_0]ENCODER_SCALE

net x-pos-fb               <=  hm2_7i96s.0.encoder.00.position
net x-vel-fb               <=  hm2_7i96s.0.encoder.00.velocity
net x-pos-fb               =>  joint.0.motor-pos-fb
net x-index-enable    joint.0.index-enable  <=>  hm2_7i96s.0.encoder.00.index-enable
net x-pos-rawcounts        <=  hm2_7i96s.0.encoder.00.rawcounts

# ---setup home / limit switch signals---

net x-home-sw     =>  joint.0.home-sw-in
net x-neg-limit     =>  joint.0.neg-lim-sw-in
net x-pos-limit     =>  joint.0.pos-lim-sw-in

#*******************
#  AXIS Y JOINT 1
#*******************

setp   pid.y.Pgain     [JOINT_1]P
setp   pid.y.Igain     [JOINT_1]I
setp   pid.y.Dgain     [JOINT_1]D
setp   pid.y.bias      [JOINT_1]BIAS
setp   pid.y.FF0       [JOINT_1]FF0
setp   pid.y.FF1       [JOINT_1]FF1
setp   pid.y.FF2       [JOINT_1]FF2
setp   pid.y.deadband  [JOINT_1]DEADBAND
setp   pid.y.maxoutput [JOINT_1]MAX_OUTPUT
setp   pid.y.error-previous-target true
# This setting is to limit bogus stepgen
# velocity corrections caused by position
# feedback sample time jitter.
setp   pid.y.maxerror 0.012700

net y-index-enable  =>  pid.y.index-enable
net y-enable        =>  pid.y.enable
net y-pos-cmd       =>  pid.y.command
net y-pos-fb        =>  pid.y.feedback
net y-output        <=  pid.y.output

# Step Gen signals/setup

setp   hm2_7i96s.0.stepgen.01.dirsetup        [JOINT_1]DIRSETUP
setp   hm2_7i96s.0.stepgen.01.dirhold         [JOINT_1]DIRHOLD
setp   hm2_7i96s.0.stepgen.01.steplen         [JOINT_1]STEPLEN
setp   hm2_7i96s.0.stepgen.01.stepspace       [JOINT_1]STEPSPACE
setp   hm2_7i96s.0.stepgen.01.position-scale  [JOINT_1]STEP_SCALE
setp   hm2_7i96s.0.stepgen.01.step_type        0
setp   hm2_7i96s.0.stepgen.01.control-type     1
setp   hm2_7i96s.0.stepgen.01.maxaccel         [JOINT_1]STEPGEN_MAXACCEL
setp   hm2_7i96s.0.stepgen.01.maxvel           [JOINT_1]STEPGEN_MAXVEL

# ---closedloop stepper signals---

net y-pos-cmd    <= joint.1.motor-pos-cmd
net y-vel-cmd    <= joint.1.vel-cmd
net y-output     => hm2_7i96s.0.stepgen.01.velocity-cmd
net y-pos-fb     <= hm2_7i96s.0.stepgen.01.position-fb
net y-pos-fb     => joint.1.motor-pos-fb
net y-enable     <= joint.1.amp-enable-out
net y-enable     => hm2_7i96s.0.stepgen.01.enable

# ---Encoder feedback signals/setup---

setp    hm2_7i96s.0.encoder.01.counter-mode 0
setp    hm2_7i96s.0.encoder.01.filter 1
setp    hm2_7i96s.0.encoder.01.index-invert 0
setp    hm2_7i96s.0.encoder.01.index-mask 0
setp    hm2_7i96s.0.encoder.01.index-mask-invert 0
setp    hm2_7i96s.0.encoder.01.scale  [JOINT_1]ENCODER_SCALE

net y-pos-fb               <=  hm2_7i96s.0.encoder.01.position
net y-vel-fb               <=  hm2_7i96s.0.encoder.01.velocity
net y-pos-fb               =>  joint.1.motor-pos-fb
net y-index-enable    joint.1.index-enable  <=>  hm2_7i96s.0.encoder.01.index-enable
net y-pos-rawcounts        <=  hm2_7i96s.0.encoder.01.rawcounts

# ---setup home / limit switch signals---

net y-home-sw     =>  joint.1.home-sw-in
net y-neg-limit     =>  joint.1.neg-lim-sw-in
net y-pos-limit     =>  joint.1.pos-lim-sw-in

#*******************
#  AXIS Z JOINT 2
#*******************

setp   pid.z.Pgain     [JOINT_2]P
setp   pid.z.Igain     [JOINT_2]I
setp   pid.z.Dgain     [JOINT_2]D
setp   pid.z.bias      [JOINT_2]BIAS
setp   pid.z.FF0       [JOINT_2]FF0
setp   pid.z.FF1       [JOINT_2]FF1
setp   pid.z.FF2       [JOINT_2]FF2
setp   pid.z.deadband  [JOINT_2]DEADBAND
setp   pid.z.maxoutput [JOINT_2]MAX_OUTPUT
setp   pid.z.error-previous-target true
# This setting is to limit bogus stepgen
# velocity corrections caused by position
# feedback sample time jitter.
setp   pid.z.maxerror 0.012700

net z-index-enable  =>  pid.z.index-enable
net z-enable        =>  pid.z.enable
net z-pos-cmd       =>  pid.z.command
net z-pos-fb        =>  pid.z.feedback
net z-output        <=  pid.z.output

# Step Gen signals/setup

setp   hm2_7i96s.0.stepgen.02.dirsetup        [JOINT_2]DIRSETUP
setp   hm2_7i96s.0.stepgen.02.dirhold         [JOINT_2]DIRHOLD
setp   hm2_7i96s.0.stepgen.02.steplen         [JOINT_2]STEPLEN
setp   hm2_7i96s.0.stepgen.02.stepspace       [JOINT_2]STEPSPACE
setp   hm2_7i96s.0.stepgen.02.position-scale  [JOINT_2]STEP_SCALE
setp   hm2_7i96s.0.stepgen.02.step_type        0
setp   hm2_7i96s.0.stepgen.02.control-type     1
setp   hm2_7i96s.0.stepgen.02.maxaccel         [JOINT_2]STEPGEN_MAXACCEL
setp   hm2_7i96s.0.stepgen.02.maxvel           [JOINT_2]STEPGEN_MAXVEL

# ---closedloop stepper signals---

net z-pos-cmd    <= joint.2.motor-pos-cmd
net z-vel-cmd    <= joint.2.vel-cmd
net z-output     => hm2_7i96s.0.stepgen.02.velocity-cmd
net z-pos-fb     <= hm2_7i96s.0.stepgen.02.position-fb
net z-pos-fb     => joint.2.motor-pos-fb
net z-enable     <= joint.2.amp-enable-out
net z-enable     => hm2_7i96s.0.stepgen.02.enable

# ---Encoder feedback signals/setup---

setp    hm2_7i96s.0.encoder.02.counter-mode 0
setp    hm2_7i96s.0.encoder.02.filter 1
setp    hm2_7i96s.0.encoder.02.index-invert 0
setp    hm2_7i96s.0.encoder.02.index-mask 0
setp    hm2_7i96s.0.encoder.02.index-mask-invert 0
setp    hm2_7i96s.0.encoder.02.scale  [JOINT_2]ENCODER_SCALE

net z-pos-fb               <=  hm2_7i96s.0.encoder.02.position
net z-vel-fb               <=  hm2_7i96s.0.encoder.02.velocity
net z-pos-fb               =>  joint.2.motor-pos-fb
net z-index-enable    joint.2.index-enable  <=>  hm2_7i96s.0.encoder.02.index-enable
net z-pos-rawcounts        <=  hm2_7i96s.0.encoder.02.rawcounts

# ---setup home / limit switch signals---

net z-home-sw     =>  joint.2.home-sw-in
net z-neg-limit     =>  joint.2.neg-lim-sw-in
net z-pos-limit     =>  joint.2.pos-lim-sw-in


#******************************
# connect miscellaneous signals
#******************************

#  ---HALUI signals---

net axis-select-x  halui.axis.x.select
net jog-x-pos      halui.axis.x.plus
net jog-x-neg      halui.axis.x.minus
net jog-x-analog   halui.axis.x.analog
net x-is-homed     halui.joint.0.is-homed
net axis-select-y  halui.axis.y.select
net jog-y-pos      halui.axis.y.plus
net jog-y-neg      halui.axis.y.minus
net jog-y-analog   halui.axis.y.analog
net y-is-homed     halui.joint.1.is-homed
net axis-select-z  halui.axis.z.select
net jog-z-pos      halui.axis.z.plus
net jog-z-neg      halui.axis.z.minus
net jog-z-analog   halui.axis.z.analog
net z-is-homed     halui.joint.2.is-homed
net jog-selected-pos      halui.axis.selected.plus
net jog-selected-neg      halui.axis.selected.minus
net spindle-manual-cw     halui.spindle.0.forward
net spindle-manual-ccw    halui.spindle.0.reverse
net spindle-manual-stop   halui.spindle.0.stop
net machine-is-on         halui.machine.is-on
net jog-speed             halui.axis.jog-speed
net MDI-mode              halui.mode.is-mdi

#  ---coolant signals---

net coolant-mist      <=  iocontrol.0.coolant-mist
net coolant-flood     <=  iocontrol.0.coolant-flood

#  ---probe signal---

net probe-in     =>  motion.probe-input

#  ---motion control signals---

net in-position               <=  motion.in-position
net machine-is-enabled        <=  motion.motion-enabled

#  ---digital in / out signals---

#  ---estop signals---

net estop-out     <=  iocontrol.0.user-enable-out
net estop-out     =>  iocontrol.0.emc-enable-in

#  ---manual tool change signals---

net tool-change-request    <= iocontrol.0.tool-change
net tool-change-confirmed  => iocontrol.0.tool-changed
net tool-number            <= iocontrol.0.tool-prep-number

#  ---Use external manual tool change dialog---

loadusr -W hal_manualtoolchange
net tool-change-request    =>  hal_manualtoolchange.change
net tool-change-confirmed  <=  hal_manualtoolchange.changed
net tool-number            =>  hal_manualtoolchange.number

#  ---ignore tool prepare requests---
net tool-prepare-loopback   iocontrol.0.tool-prepare      =>  iocontrol.0.tool-prepared

Anyone know what I'm doing wrong?

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18 Mar 2024 03:25 #296171 by PCW
Could be a cable or 5V power option issue

Valid Power options:

7I96S supplies 5V power:
7I96S W6 UP
7I85S W3 UP
7I85S P1 unconnected

External 7I85S 5V power
7I96S W6 DOWN
7I85S W3 DOWN
5V supplied to 7I85S P1



 

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19 Mar 2024 00:48 - 19 Mar 2024 00:58 #296278 by ltcnc
I checked the cable with a multimeter and it seems like the pinout is correct (DB25 matches this link ccm.net/computing/hardware/10101-db25-connector/, IDC 26 seems like typical IDC pinout, assuming pin 1 is marked by the white box on the silkscreen.)

I've been powering the board with a separate 5V line. I also tested with cable power from the FPGA board, but still didn't get the encoder reading. (For whatever it's worth, I don't see the LED light on the 7i85s when I use cable power instead.)

I also tried connecting the encoder to the encoder input of the 7i96s but still no reading. I also tried a separate motor through the 7i85s, but again no reading. This is the motor www.omc-stepperonline.com/ts-series-1-ax...-supply-1-clts48-v41
Last edit: 19 Mar 2024 00:58 by ltcnc.

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19 Mar 2024 02:08 #296283 by PCW
If you don't get the 7I85 power LED illuminated with cable power, that
is:

7I96S supplies 5V power:
7I96S W6 UP
7I85S W3 UP
7I85S P1 unconnected

That really suggests a cable issue.

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19 Mar 2024 11:39 #296311 by ltcnc
Are you able to confirm that the pinout I mentioned in the previous post is correct? I'm not able to tell from the data sheet what the expected pinout is supposed to be, but it seems to me that the cable I'm using is standard for both IDC 26 and DB25. I confirmed that all the pins are good with a multimeter. (Pin 1 DB25 is connected to pin1 IDC26, Pin2 is connected to pin2, etc.) Probably not very helpful, but this is the cable: www.ebay.com/itm/234451277144

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19 Mar 2024 16:08 #296330 by PCW
That's not an IDC DB25 and appears to have the incorrect pinout.

It should be:
HDR26  DB25
1           1
2           14
3           2
4           15

etc

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19 Mar 2024 17:26 #296333 by ltcnc
Resoldered the connector and I can finally see the encoders! (And power the 7i85s from the 7i96s.) I was definitely confused about how the pinout on that cable should work. Thanks a million!

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19 Mar 2024 18:15 #296335 by PCW
Yeah, unfortunately there are 2 "standards"
The cable you have (well the female version)
is often used for motherboard parallel ports.
While the IDC pinout (that works with Mesa cards) 
is more often  used for add-in cards.

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