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Max Current no Effect - force control

Posted: Thu May 02, 2019 5:09 am
by PdoubleU

Im am using Roboclaw 2x15
IN Ion studio, general setting gives the options to determine a Max Current for each motor. But this value actually seem to have no effect:

We are trying to move to a defined position using the position control tab. When the movement is beeing executed and I am trying to hold the axis back by hand, the M1Current immediately went up to 40-50 Amps.

In my thinking when reducing the M1MaxAps this value should be limited, right? But whatever value I put in, the Current always goes up to 40-50 Amps.

The only effect I recognize is what I put the max current to a very low value, and trying to move the axis by PWM, fo rexample, roboclaw immediately goes into M1 Over Current error without moving.

Could you please help with that?

Is there any other way to control the force of a movement?

Re: Max Current no Effect - force control

Posted: Thu May 02, 2019 10:13 am
by Basicmicro Support
I tis unlikely but there could be a problem with the current sensor. It is just an analog input measuring the curretn across a shunt resistor so there isnt much that can go wrong though.

On a 2x15 controller 40 to 50 amps isnt usually possible since the hard current limit is 30amps at 25C so I expect it is a current sensor hardware problem.

Can you confirm the current reading is the one shown in Motion Studio? Also please confirm you are using the latest firmware 4.1.33.

Just to be sure, reset the unit to defaults(Device menu) and then set all your settings one more time. Then test in PWM settings by slowly increasing power while olding the motor still(or while under a constant load). The current should rise pretty linearly with the power level under stall or constant current.

Also is there anything unusual about your motor(s)? Do you have specifications for them?

Re: Max Current no Effect - force control

Posted: Wed Jun 05, 2019 2:44 am
by PdoubleU
Hi again,

Sorry for the late reply.

I have tried multiple boards now. The problem is just always there. Even if in Ion Studio I go to the settings page and enter a "10" for max current and then driving the motor via the positioning tab the current reading easily goes to 35-40 Amps (depending on the PID settings of course). Am I missing a point?


Re: Max Current no Effect - force control

Posted: Thu Jun 06, 2019 10:18 am
by Basicmicro Support
Well, your main problem is going into "Ion Studio". That is old software. Please uninstall it and download Basicmicro Motion Studio. Ion Studio is no longer updated and will not automatically upgrade to Basicmicro Motion Studio.

Make sure your firmware is up to date after installing the new software and re-test and get back to me with the results. We can work from there.