JVL MAC050 User Manual page 73

2.12 Absolute Multiturn Encoder
Option 3 (the unprecise one):
Write a value to the target position register 3 (P_SOLL) that is the actual position plus/
minus the distance to move. This is unsafe/inaccurate because the actual position may
have changed in the time it took to read the value, do the calculation and write back the
new target position. This may still work on some applications, or even be desirable, but
note that a position error might accumulate over time.
In some applications, it may be useful to prepare several position distances in the differ-
ent P1 through P8 registers, and then activate them using different FastMac commands.
2.12.10 ePLC programming - Resetting the position to 0
If a ePLC program is resetting the encoder zero point it must be done as follows.
When the "invert motor direction" IS NOT enabled the offset can be changed by this
formula: Abs.Enc.Offset = 0 – Abs.Enc.Pos.
When the "Invert motor direction" IS enabled the offset can be changed by this formula:
Abs.Enc.Offset = 0 + Abs.Enc.Pos.
Following examples show how to make program commands for resetting the position.
Please notice that the "Set special command to 2" (line 7 and line 12) will save the new
encoder offset value in order to make it effective and the motor will be reset and restart.
JVL A/S - User Manual - Integrated Servo Motors MAC050 - 4500
Only MACxxx-yy-
Insert this little program if motor
direction is set to normal
Insert this little program if motor
direction is set to «inverted»
TT1549-01GB
F
zzz
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