B
Ben
- Jan 1, 1970
- 0
Hi,
I need help. I have been in electronics design for almost 20 years but this
is getting me down.
I had to design a stepper controller for a linear actuator from Haydon. It
has a worm screw and a nut and it is used to lift a panel to exact
positions.
I have a controller/driver chip like PBL3717 and I drive it from a
Micdoprocessor .
The controller chip uses a chopper drive with the 5V motor running off 40V @
I max=560mA
Motor is 200 step/rev bipolar.
I am stepping in fullstep mode with 2 coild nergized at all times.
The 4 step phases are:
A1A2 B1B2
0 1 0 1
0 1 1 0
1 0 1 0
1 0 0 1
I am stepping batches of 400 steps at a time and I repeat this over and
over.
I use a accelerate and decelerate routine as follows:
Step 0-23 = accelerate 0 to 635 stpes/sec
Step 24 - 374 = run at 635 steps/sec
Step 374 - 399 = decelerate to - and then stop.
Problem:
Motor starts runs and stops correctly but as I repeat the batches of 400,
suddenly, RANDOM (!) motor starts and runs at a higher (audible buzz) speed
in the opposite direction.
This is NOT caused by the drive sequence or anything in the pulses. In fact,
there is no electrical difference at all in the driving. The motor just does
his. The next batch will be ok again. Sometimes it works fine for 30 an
dmore batches and suddely it does it again.
Has anyone come across a problem like this and how is it best solved?
I tell you, stepper motors are not simple when resonance, acceleration and
exact position all come into it simultaneously!
Regards
Bernt
I need help. I have been in electronics design for almost 20 years but this
is getting me down.
I had to design a stepper controller for a linear actuator from Haydon. It
has a worm screw and a nut and it is used to lift a panel to exact
positions.
I have a controller/driver chip like PBL3717 and I drive it from a
Micdoprocessor .
The controller chip uses a chopper drive with the 5V motor running off 40V @
I max=560mA
Motor is 200 step/rev bipolar.
I am stepping in fullstep mode with 2 coild nergized at all times.
The 4 step phases are:
A1A2 B1B2
0 1 0 1
0 1 1 0
1 0 1 0
1 0 0 1
I am stepping batches of 400 steps at a time and I repeat this over and
over.
I use a accelerate and decelerate routine as follows:
Step 0-23 = accelerate 0 to 635 stpes/sec
Step 24 - 374 = run at 635 steps/sec
Step 374 - 399 = decelerate to - and then stop.
Problem:
Motor starts runs and stops correctly but as I repeat the batches of 400,
suddenly, RANDOM (!) motor starts and runs at a higher (audible buzz) speed
in the opposite direction.
This is NOT caused by the drive sequence or anything in the pulses. In fact,
there is no electrical difference at all in the driving. The motor just does
his. The next batch will be ok again. Sometimes it works fine for 30 an
dmore batches and suddely it does it again.
Has anyone come across a problem like this and how is it best solved?
I tell you, stepper motors are not simple when resonance, acceleration and
exact position all come into it simultaneously!
Regards
Bernt