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Controlling torque outside of torque mode

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(@Techsmart07)
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I have a SM23165D-BRK smartmotor (Firmware 5.0.3.41) connected to 2 other smartmotors on a 3-axis scanner. Each motor is able to control the axis freely, when nothing is placed on it. However, when the scanner equipment is attached, the Z axis motor (the model listed above) is unable to lift it, giving an excessive position error. However, if I go into torque mode and raise the torque to around 2500, it is able to slowly lift the equipment. The motors have shown that they are able to lift the equipment, but are unable to compensate for the weight if in position/velocity mode. Is there a setting I can change/modify to allow the scanner to exert more torque if the need arises? If not, is there a way to set a base torque that the scanner bases its movements on? Sort of like setting the origin to 0, setting a counter-clockwise torque of something like 2000 to be default and whenever a move is called, it raises or lowers torque appropriately. The structure is 19 lbs, and if I remember correctly,the motors are rated to handle 25 lb. loads. I would prefer keeping the equipment in all position/velocity mode if possible.

thanks for any help.

Edit - I also had another question come up from something a coworker brought up. currently I have 2 limit switches on the scanner, one positive one negative. Normally, I would just do EILN and EILP on the switches. However, I would need both switches to be normally closed (if memory serves), and one set of switches is normally opened. I am unable to swap them, so I was wondering if there was a way to tell the smartmotor to invert the IO on a certain pin/limit.

 
Posted : 28/01/2013 9:36 am
(@csearcy)
Posts: 316
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Two things you can try.
1. Set the EL variable to a larger value than the default (1000 encoder counts). I would try 8000 for testing.
2. Use the KG tuning parameter to offset the gravitational load.

EILP and EILN will only work with normally closed switches. The workaround is to create an interrupt on the normally open switch and write your own code in the subroutine that is called.

 
Posted : 28/01/2013 4:02 pm
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