JVL MAC050 User Manual page 69

2.12 Absolute Multiturn Encoder
2.12.4 For MAC800/1200 users only:
Please observe the motor position scaling used. The motor resolution is by default 8000
counts/rev. The absolute build in encoder uses 8192 counts/rev. therefore scaling is done
when the position is reset. This may cause some confusion since the actual shaft position
is not the same as the absolute encoder position.
So with the motor in position mode, ordering a movement to motor position = 100.000
counts, results in a encoder position of 97.656 due to the larger encoder resolution (8192
counts/rev).
2.12.5 Resetting the position when not using MacTalk.
The procedure for adjusting the an encoder offset and thereby resetting a certain motor
position to be zero position (Actual position = 0) is basically described in 4 steps:
1. Read register 226 which is the absolute encoder position value.
2. Multiply the position value (from above) by -1 (inverse the sign).
Notice: If 'Inverted motor direction' is selected, skip this step and proceed to step 3.
3. Store the value in register 225 which is the offset register.
4. Save the offset value permanently in the flash memory. This procedure is basically
performed from the command register 211 by writing 211 = 2. When using a bus
module please refer to the manual of actual type of bus module to do the save in flash
operation. Please notice that if the value is not stored in the flash memory the zero
point is lost after a power cycle.
For MAC800/1200 users:
The MAC800/1200 is default set to a resolution of 8000 counts/rev. compared to other
motors which have 8192 counts/rev. as default.
The MAC800/1200 default resolution can be changed from 8000 to 8192 by setting bit
21 to 0 in register 39 (HW_SETUP). Default it is set to 1.
If the default has not been changed the 4 step procedure shown above can simply be used
If the default have been changed and the MAC800/1200 is set to 8192 counts/rev. (bit
21=0)
1. Read register 226 which is the absolute encoder position value.
2. Register 225 = - (8192*(register 226)) / 8000. Remember that the result must be ne-
gated before entering it into register 225.
3. Save the offset value permanently in the flash memory. This procedure is basically
performed from the command register 211 by writing 211 = 2. When using a bus
module please refer to the manual of actual type of bus module to do the save in flash
operation. Please notice that if the value is not stored in the flash memory the zero
point is lost after a power cycle.
JVL A/S - User Manual - Integrated Servo Motors MAC050 - 4500
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