Encoder
Parameters/Attributes
Dec 2021
ATM60 / ATM90 / KHK53
29
6.4.4 Preset Value
The encoder supports, as a Class 2 function, electronic adjustment (preset) to a user-defined
position value.
Definition of the preset value (4-bytes) with a max. resolution of 'nn' bits. -- (2**
nn
).
Byte_1 (MSB)
Byte_2
Byte_3
Byte_4 (LSB)
31 30 29 28 27 26 25 24
23 22 21 20 19 18 17 16
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
m
x x x . x x
Number of revolutions (1...8192)
CPR (1...8192)-[steps per rev.]
[CMR]
To activate the preset value, set bit_31 to one (
1
) (marked as
m
). The actual preset value is
predetermined as an nn-bit value. -- (here: 26)
The time needed for a valid activation is determined by the cycle time of the transmission, and
is dependent on the arrangement of all subscribers in the entire network.
After a valid activation of the preset value, the current position value is set to this value (see
display in module of the DP Master).
Disabling the function: - Set bit_31 to zero (
0
).
Example: Seen as UDINT value (81,938
D
) in the "Big Endian" data format.
Byte_1 (MSB)
Byte_2
Byte_3
Byte_4 (LSB)
Active
8 0 0 1 4 0 1 2
[
8
0.01.40.12]
hex
Byte_1 (MSB)
Byte_2
Byte_3
Byte_4 (LSB)
not active
0 0 0 1 4 0 1 2
[00.01.40.12]
hex
Activation by Bit_31 in the master device can lead to a display format with nega-
tive numerical value!
Activation of a new preset value always results in a diagnostic message with low
priority being triggered. This detail is contained in the FDL header of the data ex-
change response message. The Master can then request a diagnostic message,
to obtain information on the 'offset' value of the encoder!
The preset function is not intended for dynamic adjustment processes. The func-
tion is meant for electronic adjustment during commissioning, to allocate a certain
position value to any mechanical shaft position of the encoder. In case of con-
stantly recurring activation of the preset function, the corresponding memory lo-
cations in the EEPROM are destroyed, over time!
The use of the preset function leads to a change in the position value output. This
could cause an unexpected movement which may lead to damage of the system,
other objects or bodily harm.
