Machine and cam data
9.9 Example: Adjusting the absolute encoder
FM 352 electronic cam controller
Operating Instructions, 05/2011, A5E01071724-03
85
Result of "Set reference point"
The Set reference point operation creates the following relationship between the encoder
and coordinate system:
The reference point coordinate on the axis (-125) is assigned to the encoder value (1798)
which is determined by the absolute encoder adjustment.
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DEVROXWHHQFRGHUDGMXVWPHQW
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6/6
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The encoder returns 2048 unambiguous values. The working range is determined by the
software limit switches. However, due to the set resolution of 1 mm/pulse, the encoder's
working area extends beyond the set software limit switch range.
At the set resolution, the working range is already covered by 2001 values. In the example,
this produces a "remainder" of 47 pulses which symmetrically enclose the working range.
Alternative: Mechanical encoder adjustment
To achieve a correct relationship between the coordinate system and the encoder, perform
the following:
1. Move the axis to a reproducible position (for example, the software limit switch start).
2. Enter this coordinate value in the machine data as the reference point coordinate.
3. Read the encoder value indicated at this position in the service screen form of the
programming interface.
4. Enter this value as the absolute encoder adjustment in the machine data.
The parameters will thus always return the correct actual value.
As an alternative to steps 3 and 4, you can also set the encoder to zero by means of a
"Reset" signal (if this exists), and then enter the value "0" as the absolute encoder
adjustment in the machine data.
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