[Barry_CNC]

Hi I have an Omron R88M-U1K0315V-S1 brushless servo motor which I am planning to drive with a Copley Controls Xenus.

The motor has an incremental encoder fitted as standard with differential X, Y and S (Z). The manual I have indicates that I should be expecting a single transition per turn on the S(Z) output marking a specific point in the motors rotation. As there are no halls in the motor I guess this could be used for commutation?

I have checked all outputs from the incremental encoder using an oscilloscope A- and A+ and B- and B+ are working as expected producing a pulse train.

However, Z+ and Z- are also producing a pulse train throughout the motors rotation rather than a single transition per revolution. The pulses from the Z+ and Z- are both 5V and well shaped.

Is this a fault? Perhaps miss alignment of the read head so its not reading the Z track properly?

Thanks

Barry

[Al_The_Man]

The Z pulse is usually used as a home reference, the servo is moved until it see's the switch and then goes into low rpm until the marker is seen.
this is then registered as zero.
One output is usually not the commutation method, three are usually required, one for each winding.
Al.

[Barry_CNC]

Thanks Al, the encoder I have is a UTOPH-81AWF.
The guys from OMRON have indicated that the pulse train on the Z/Z- channels are correct. Apparently superimposed on the single Z Pulse is commutation data that the OMRON servo drive interprets. The A/A- and B/B- appear to work as normal for an encoder.
Regards
Barry