Hi,
I have a desk with linear actuators (without controller) where in the manual from the manufacturer i find this :


I then found how the plug on the controller is looking so i know which pins are what :


In the manual for the telescopic pillar i found following :






and now i wanted to buy a Dual DC Motor Driver to control these. From the specs they can be driven by 24V and a 5A power supply.


but i am unsure whether i can use PWM and especially unsure how not to trip the limit switch so that i can't move the table again. I am not sure i interpret the diagram at the top correct but does the diagram and the description from the manual mean that if both limit switches a re tripped over i can move the table anymore so i have to physically open the pillar ? The table 3 meter wide and has alot of things on so that would be a major challenge.

/mihai

 

The limit switches prevent the controller from running the telescopic pillar too far in one direction or the other. When a limit switch is opened, the motor stops but can be operated in the opposite direction.

From the schematic you don't need PWM if you use a 24 volt power supply.

 

but i understand the diagram that if both limit switches are activated i can't move the actuator regardless of the direction or am i wrong ?

 

I tried applying carefully 0-24 V to motor + and motor - with a max limit current on 0A and nothing happened to either legs which leads me believe there is something more to be done. I know the motors work because i test the motors directly before everything was assembled but in doubt the electronics described above with the limit switches does something that hinders me to operate the motors.

 

If the limit switches are at opposite ends of the travel (which is the only way they make sense to me) they cannot both be activated at the same time. You can always get to the point where the limit switch trips but no further, but you can always back away from that position.

How much torque do you think you can get from the motor with 0 amps flowing through its windings.

Everything sound like it is ok. Try the 5 amps specified.

 

If the limit switches are at opposite ends of the travel (which is the only way they make sense to me) they cannot both be activated at the same time. You can always get to the point where the limit switch trips but no further, but you can always back away from that position.

How much torque do you think you can get from the motor with 0 amps flowing through its windings.

Everything sound like it is ok. Try the 5 amps specified.

Sorry I meant 1.5A limit, it was pulling no current at 24v so something is not right.

 

If the limit switches are at opposite ends of the travel (which is the only way they make sense to me) they cannot both be activated at the same time

I bet one of the limit switches is wired backwards. The controller thinks the limit switch has been hit, preventing motion in that direction. It's also possible both switches are wired backwards. IF they can not be wired incorrectly, perhaps the upper limit switch has been installed on the lower end of the travel. My money is on a mis-wiring of the limit switches or the switches may be installed incorrectly.

Another possibility is the bar that taps the switches may be installed backwards. Perhaps a notch that the switch is looking for when the limit is reached may be 90 or 180˚ reversed. If the TS has done the assembly correctly then it should work. Something's a-miss.