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Encoder Decode Problem


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I just reset my UMAC using :



I0..8191 = 0

P0..8191 = 0

Q0..8191 = 0

M0..8191->*M0..8191 = 0




after that i setup my motor using PMAC setup pro. but i found problem with encoder decode. i wanted to use 4x quadrature decode but i seems that its only detect 1x decode. any suggestion to solve this problems ?



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I generally would not recommend setting all the I variables to zero. The $$$*** will set them to factory default.

Default for the M-vars is ->* =0, and the P & Q-vars will also be cleared to zero. In addition, the UNDEFINE ALL is unnecessary.


The I vars controlling encoder decode recognize '0' as the setup for pulse & direction decode.

When you issue I0..8192=0, PMAC is simply decoding using the zero format per your instruction.

Default value for decode is I7mn0=7 for CCW quadrature.


Generally easier to start from the factory defaults instead of clearing to zero.

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Reset with $$$***

Make sure encoder connections are correct

Set the addressing on your 24E2(A) for whatever motors it represents (careful to observe that addressing for the servo IC begins at 2. 0&1 are reserved for 'on board' systems. This means I72xx correlates to Motor #1. See the 24E2 manual - Hardware Setup)

Enable motor by setting Ixx00=1 (Only Motor #1 is enabled after reset)

The Encoder Conversion Table for motors #1 thru 8 are configured by default for quadrature decode.

If you are checking Motor #9 or greater, you will need to make the appropriate entry to the encoder conversion table starting at I8000.

Manually rotate motor/encoder

Should see counts from the encoder as x4 quadrature ccw+


If there are no counts:

Check connections, cable, plug, etc.

Check for power to encoder at pins 7&8 (assume terminal block connections)

Check board configuration for Single ended / differential encoder signals

Verify the Encoder Conversion Table for the correct entries

Refer to the 24E2 manual

Refer to the Software Reference for ECT settings (I8000)


I am assuming that you are using Acc 24E2 cards in the local rack.

If you have a MACRO system you will need to alter a number of I-vars from the default.

If you are using MACRO, the addressing is covered in the manuals, but you may need some help to know which variables to consider.


This is NOT an adequate setup to actually run a motor, only to confirm encoder counts.


Best Regards

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