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Homing Offset - how to use?

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Motor DH102M stands vertical and has a round scale attached, marked with 0..360. Real "Vertical" (0 of my scale) does not correspond to motor's encoder's "Vertical", difference is about 20 degrees. So, when I perform Homing, motor stops slightly not really vertical. I thought it's not a big deal, so I opened DriveGUI and estimated ROFFS parameter of my S346 to a value of actual vertical position (3370, as my scale really is from 0 to 3600). 

The ROFFS parameter can be used to assign a freely chosen absolute position as the reference position (zero position) that will be reached at the end of a homing movement.

 - stated in a Help file.

Next, I started my app, made some movements back and forward, then made Homing. As a result - motor stopped not in my 0, again 20 degrees from vertical (as previous), but now it thinks it's position is 3370. I monitor it with PDO 0x6064. 

It stops in a point where PRD is 0, but shows a position value equals to ROFFS. 

What is correct way to set homing position?

 

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2 Answers

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Actually, found a solution. It was not obvious for me, as it is concerned to topic Encoder Emulation (first I thought Why emulation? My encoder is real):

ENCOUT = 524288 makes the whole circle as 524288 counts and ENCZERO then defines required offset as (ENCOUT/360)*337 = about 490790

 

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Hello,

There could be different reasons why the offset is not working properly. First you should ensure that the offset at the actual position is working in the way you need to have it.

With Roffs you set the absolute position after the homing to this value.

If you have an absolute encoder than it might be worse for you to work with the parameter ROFFSABS:

The ROFFSABS parameter is used with an absolute encoder (multi-turn, homing to reference point is also possible)
The ROFFSABS sets an offset to the absolute encoder position. This procedure is executed by drive power on. The parameter must be saved in the EEPROM (using the SAVE command) after every alteration of the ROFFSABS variable, and the amplifier must then be switched off and on again (COLDSTART command).

Example:
If a position 10000 (PFB) is shown when the amplifier is switched on with ROFFSABS = 0, ROFFSABS = –10000 will shift the position to the value 0.

If this also doesn't work, please forward additional information about your system and the parameter file to: [email protected]

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