External motor motion skipping

Hey guys,

I have been working with KRC4 8.6.6, it is connected to 8 external motors , 3 motors are used as robot motor while 5 are asynchronous external axes.

To make it clear i have attached a picture regarding the connections. All the motors works fine except for one which is E4 motor, E4 motor is endless type and uses degrees for position measurement and this motor is also coupled because its position has to reset(coupling/decoupling method) to zero at certain location. For this motor 1 degrees is 1m.

This motor has 3 different type of motion depending in situation and this motions are under conveyor_auto2ok(). This sub program is called under test( ), as you can see in below code.

Inside conveyor_auto2ok() program, there are 3 stop_points, stop_point 1 and 3 are working perfect, but somehow stop_point 2 doesnt work as it should.

the exact problem is in the external mode stop_point 2 motion is missing in the loop of test(). By the way this skipping of motion does not happen in T2 mode, happens only in external mode.

when the program runs for first time it completes conveyor_auto2ok(1), then moves toward conveyor_auto2ok(2) and conveyor_auto2ok(3), all the motion are completed in first round, but then comes loop where it should repeat conveyor_auto2ok(2) and conveyor_auto2ok(3) but for some unknown reason it skips through conveyor_auto2ok(2) and only completes conveyor_auto2ok(3).

if i do the same program in T2 mode this does not happen it works nice and smooth. but not in external mode. is there any explanation for such behaviour. i have tried to check the position variable that commands motor to move to certain position i.e E4_relative.E4 . E4_relative.E4=1.05 just before motion command and after motion command. but there is no movement from motor at all.

is there anything that i should know about ASYPTP motion command? i dont understand how motion works in T2 mode but not in External mode.

======================= test.SRC ======================

DEF test( ) ; main program for testing the conveyor/E4 motor (Asynchronous)

conveyor_auto2ok(1)

asycancel 4

wait sec 2

loop

conveyor_auto2ok(2)

wait sec 2

conveyor_auto2ok(3)

asycancel 4

endloop

END

======================= test.SRC ======================

==========================conveyor_auto2ok.SRC===================

DEF conveyor_auto2ok(stop_point:in)

INT stop_point

E4_relative=$AXIS_ACT

$OV_ASYNC=50

wait sec 0

if stop_point==1 then

E4_relative.E4 = 5;

wait for $async_state<>#busy

ASYPTP E4_relative ;motion command for conveyor.

wait for $async_state<>#busy

Reset_2()

endif

if stop_point==2 then

if pallet_width_HMI>1200 then ; position according to pallet size.

E4_relative.E4 = E4_relative.E4 + 1.05 ;positions are in degrees.

else

E4_relative.E4 = E4_relative.E4 + 0.78 ;positions are in degrees.

endif

wait sec 3

ASYPTP E4_relative ;motion command

wait for $async_state<>#busy

endif

if stop_point==3 then

N=N+1

if (N<13) then

E4_relative.E4 = + 1.79; back to 0

else

E4_relative.E4 = 1.79-0.01; back to 0

N=0

endif

ASYPTP E4_relative ;motion command

wait for $async_state<>#busy

Reset_2() ;reset subprogram resets to zero after reaching the final position.

asycancel 4 ;just incase to avoid the extra movement

endif

END

==========================conveyor_auto2ok.SRC===================

SkyeFire

Stop point 1 and 3 are fine they do execute well.

About stop point 2, when i checked the e4_relative.e4 just before it starts to move the value was 1.05 that means it went through the IF statement. but again mysteriously skipped the motion. Also i did add monitoring variable that goes true inside the IF statement of stop point 2 , the monitoring variable went to true as well.

This is executing in robot interpreter.

ASYPTP point

WAIT FOR $ASYNC_STATE<>#IDLE ; ensure motion starts

WAIT FOR $AYNNC_STATE<>#BUSY ; motion complete, or cancelled

what if do it like this:

ASYPTP point

   WAIT FOR $ASYNC_STATE==#BUSY ; if motor does not move it will wait in this line.

   WAIT FOR $ASYNC_STATE<>#IDLE ;TO ENSURE THE MOTOR HAS STARTED

   WAIT FOR $ASYNC_STATE<>#BUSY ;TO ENSURE MOTOR HAS COMPLETED THE MOTION.

About this i can check if that works, it will take few days or week probably.

How do i use SPTP or LIN for external motor, it always gives me error regarding the frame, pos?

SkyeFire panic mode

lets say same E4 motor that used in the above code, what if i wanted to use the LIN motion for it,

because it is asynchronous motor we use ASYPTP,

what if we synchronize it ? synchronization is possible then probably LIN or SLIN should be possible as well. isn't it ?

panic mode

In the image attached, there is an example that says external axes i.e. motor can be moved synchronously or asynchronously. i am not talking about asynchronous motion, but if the external axes are made synchronous would they move with PTP, i think they do,

but it does not mention anything about SLIN or LIN motion, so i am asking can they move with SLIN or LIN command as well.

panic mode thankyou very much, I got my answer.

panic mode  SkyeFire

hey guys i am summoning you here,

lets recap this thread little bit, so there was a problem of skipping of motion in Automode and external mode but not in the T2 mode, code can be found up above in the thread,

SkyeFire gave an excellent solution regarding this, but it still did not work, the skipping kept on happening randomly like after 4/5 or even after 10 loops. so i went throug the whole program found out there was ASYPTP motion command running all the time in SPS sub.

DEF  E4relative ( )

E6AXIS E4_relative

E4_relative=$AXIS_ACT

$VEL_EXTAX[4]=100

$ACC_EXTAX[4]=100

$OV_ASYNC=100

if (($ASYNC_STATE<>#BUSY) and (E4start_REL== true)) then

E4_relative.E4 = E4_relative.E4 + E4_input_REL

endif

ASYPTP E4_relative

END

There was this E4relative(), that was running in the SPS sub, E4_relative was the common name used which was not intentional, it was a mistake, i am suspecting the problem I mentioned in this same thread occurred because of this. as the SPS sub is running all the time the motor always does ASYPTP motion, since the variable is same it acquires data depending on the speed of program and SPS sub. and that would make sense if it skips the motion, i am going to make a test again soon removing the these from SPS and see if that works.

but still the mystery is that skipping doesn't happen in T2 mode, even though same thing runs in sps sub. I just wanted quick reviews regarding this issue, what is your thoughts regarding the problem?

have there been any similar mysterious problem for you guys too ?

Quote from panic mode

my thought is that there is not much to go on. "it does not work" does not describe the issue. when dealing with program issues, common approach is to post code for review. maybe there is something in SPS like this:

Code

IF $MODE_OP==#T2 THEN
  E4Relative()
ENDIF 

there is no code in sps sub like that, also i removed all the code that would affect the external axis from SPS.sub but some how it still does that skipping.

we are now trying different structure of program to run the motor. actually, this happens for certain cases only, not for all cases even though the code are same for all cases, so now we are trying a different approach to program, lets hope it goes fine.

Quote from panic mode

also setup variable overview page with key things so you can see the values of important things. that includes axis state, axis position, start flag, position increment value etc.

i have no idea what that means... why is there discrepancy in units (degree /meter). is this linear or rotary axis? why is there a need to reset position to zero and how do you keep track of that?

we did check the positions, even the program has

ASYPTP point

   WAIT FOR $ASYNC_STATE==#BUSY ; if motor does not move it will wait in this line.

   WAIT FOR $ASYNC_STATE<>#IDLE ;TO ENSURE THE MOTOR HAS STARTED

   WAIT FOR $ASYNC_STATE<>#BUSY ;TO ENSURE MOTOR HAS COMPLETED THE MOTION.

waiting for the program to be busy then not idle then not busy, it goes through all the lines, probably that means it just thinks motor moved and reached its destination and then stopped.

motor is Rotatory axis which uses degrees, because the motor was made as an endless axis as there was need of coupling and decopuling which i was not able to do it in other axis mode, only in endless mode. And coupling/ decoupling was needed to reset the motor to zero. it does the reset every 1.79 m because the application requires it to be like that.