A new field has been added to the Diax02 Multi-Axis Driver.

In almost all cases, this field should be zero. However, in some drives with high gear ratio's, we run into an issue with Absolute Encoder Travel range. The encoder can only measure 2048 motor turns on either side of zero. If the motor has to travel further than that, the reported position will invert its polarity sign when it crosses the 2048 turn boundary. Position Limits Errors, if enabled, will happen slightly before that.

The maximum travel range can be calculated by 2048 * (Gear Out/Gear In) * Feed Constant. The Travel limits will be +- this calculated value. For example, a gear ratio of 20:1 and a Feed Constant of .2" results in a travel range of +-20.48".

The Offset From Zero lets us use this range more effectively by making it appear that the zero point of the axis is in a different place. If we use our earlier example and we need the axis to travel to 24" we can shift where zero is. We can shift the zero point -10" by entering -10" in the Offset From Zero setting. This will make our travel range -10.48" and + 30.48" inches.

When referencing and sending positions to the drive, the controller lies to it. It offsets the positions it sends and the positions it gets back by the Offset by Zero value to effectively shift the travel range the drive has, into the range that we can use.

If Position Limits are being used, the must be shifted in the drive by the Offset From Zero value. For example, if the Axis upper limit is 30.48", adding the -10" offset from our example means the limit in the drive needs to be 20.48".