Machine and cam data
9.8 Determining the correct absolute encoder adjustment
FM 352 electronic cam controller
82 Operating Instructions, 05/2011, A5E01071724-03
9.8 Determining the correct absolute encoder adjustment
Definition
The absolute encoder adjustment and reference point coordinate maps the encoder's range
of values unambiguously to the axis coordinate system.
Address Name Type Start value Comment
48.0 ENC_ADJ DINT L#0 Absolute encoder adjustment
Range: 0 to (2
25
-1)
The "Absolute encoder adjustment" is used to determine the encoder value corresponding to the
reference point coordinate on the axis. The value must be less than the total number of steps of the
absolute encoder.
Procedure
After you completed the basic program, you need to define a balanced correlation between
the encoder and the coordinate system. The procedure shown in the next section is based
on the use of the programming interface.
1. Move the axis to a known and physically unambiguous, reproducible point.
This could be the "Software limit switch end".
2. Call the "Set reference point" function, using the coordinate position defined in step 1.
The FM 352 now calculates an encoder value for the reference point coordinate entered
in the channel DB (REFPT in channel DB), namely the absolute encoder adjustment. You
can view this value at the service screen for of the programming interface.
3. Enter the value from the service screen in the "Absolute encoder adjustment" field on the
"Axis" tab of the parameter assignment interface.
4. Save your parameter assignment to the corresponding parameter DB using the export
function.
5. Close the parameter assignment interface by selecting File and Exit.
6. In HW Config, download the data to the CPU.
7. Restart the CPU (cold restart) to apply the data.
Note
This adjustment is made once during commissioning. After parameters are assigned, the
FM 352 is synchronized during startup as soon as it has received a complete, error-free
encoder frame.
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