Last week I try to use the position available functionnality on the place work area with an IRB360 who needs to work at speed of 100picks/min.
Without using this the robot can handle more than 100picks/min. When I try to use the position available signal, the robot lost cycle time and was only able to run at a speed of +/- 90 picks/min.
I try to analyse the problem and found out that the signal position available was coming to late even if there are enough prosition between enter and exit. It seems that the signal goes of when the robot has place one product. I do not know when this signal is coming high again.
What could be the reason of this? Is the robot not able to work with high speed picking and the position available signal functionality?
On a conveyor outfeeder, I would expect Position Available signal to go high when the first empty place holder becomes available between the enter and exit limit. At the moment a product is placed, the signal will become low if there are no more empty place holders between enter and exit. How do you use the signal in the application ?
For me the signal goes always low when the robot place a product. But I can not say when it come back High. But I am 100% sure that there are enough position between enter and exit.
This is the rapid code :
PROC PickPlaceSeq()
Coordinated;
bNoPick:=TRUE;
WHILE bNoPick DO
stGrip:=“Grip1”;
bPosAvailable:=FALSE;
WaitDO soPosAvailable,1MaxTime:=0.2TimeFlag:=bPosAvailable;
IF bPosAvailable=FALSE THEN
Pick PickIndex{1};
IF bNoPick=FALSE Place PlaceIndex{1};
ENDIF
rPLCStop;
ENDWHILE
ENDPROC
I have also tried to use “IF DOutput(soPosAvailable)=1 THEN” instead of “WaitDO”, same result.
Hi Fabrice,
My understanding is that the position available signal works the following way:
When a position is popped from the queue using the GetItmTgt instruction, position available signal goes low. After position has been acknowledged the queue is scanned for positions between enter and exit limit and signal is updated.
We had same type of problem as you some time ago. We solved it by using GetItmTgt instead, something like:
GetItmTgt ItmSrcData{PlaceIndex{1}}.ItemSource,PlaceTargetMaxTime:=0.05TimeFlag:=to;
IF to THEN
bAvail1:=FALSE;
ELSE
AckItmTgt ItmSrcData{PlaceIndex{1}}.ItemSource,PickTarget,FALSE;
bAvail1:=TRUE;
ENDIF
Position available
This output signal is high when there is one or more items between
the enter and exit limits for the work area. (This can e.g. be used to
make post inspection.)
Post inspection
Define enter and exit limits for the post inspection conveyor
work area. When the item is between the enter and exit limits the
Position Available signal, for the post inspection conveyor work
area, will be set high and can be used by external equipment. If
the enter value is 300 mm, the Position Available signal will go
high when the item is 1.3 m from the robots origin
(base_frame_pos_x + Enter value).