UK
CANopen encoder
17
The encoder reads the current position value and calculates an offset value from
the preset value and the read position value� The position value is shifted by the
calculated offset value� The offset value can be read with the diagnostic function
(object 6509h), is stored in a non-volatile memory and reloaded at each start-up�
Only use the preset function if the shaft is stationary�
Format of the preset value
Byte
3
2
1
0
Bit
31 - 24
23 - 16
15 - 8
7 - 0
Data
2
31
- 2
24
2
23
- 2
16
2
15
- 2
8
2
7
- 2
0
object 6003h - preset value
Calculation of the preset value
6.6.2
An offset value is calculated when the encoder receives the preset value, see the
set-up calculation below� The offset value is then used during runtime to shift the
current position to the required output position, see the runtime calculation below�
In the formulas below the current position is the absolute position of the en-
coder disk after the scaling function� The calculations are made with signed
values�
Set-up calculation:
offset_value = preset_value - current_value
A previously set offset value is not included in the current position�
Runtime calculation:
output_position = current_po offset_value