Siemens SIMATIC FM 351 - Reference Point Approach Mode

8
8-11
FM 351 Positioning Function Module
EWA 4NEB 720 6001-02
After the initial parameterization further steps are necessary to create a cor-
rect relationship between the encoder and the coordinate system.
1. Set the axis to a defined reproducible point with which you are familiar
and which is physically unambiguous.
2. Call the setting Set reference point with the known coordinate.
The FM 351 now determines the correct absolute encoder adjustment
(= 1798) for the reference-point coordinate entered in the machine data.
You can read out this value with the parameterization interface in the ser-
vice mask.
3. Enter the read-out value as a new value in the machine data Absolute
encoder adjustment.
4. Save the machine data.
5. Load the data under the configuration interface to the CPU. The CPU
must be in the STOP state for this. The FM 351 is then directly parame-
terized.
Note
You carry out this adjustment only once when you set up the FM 351. After
parameterization, the FM 351 is now synchronized on starting.
The relationship appears as follows after Set reference point:
SLESLS
Axis
–1000 10000
Value of absolute encoder
0
2048
REF
–125
1798
Value found for the 875
Unambiguously covered travel range with this encoder
1024–1023
absolute encoder
adjustment
Determining the
Correct Absolute
Encoder Adjust-
ment
Result after Set
Reference Point
Machine Data and Increments