Product description
Chapter
3
Operating Instructions
12
© SICK AG
•
Germany
•
All rights reserved
8014012/1EF3/2021-12-08
Subject to change without notice
3.4.4
Preset
A3M60 Basic
The preset value is applied in message IO<04 or IO<08 as an output from the PLC.
With the aid of a preset value the encoder can be set to any position within the measuring
range. The value is transmitted in two data words (4 bytes) in the output data.
The preset value is activated by setting bit 31. The current position value is only set to
the preset value if bit 31 was set to “0” in the previous cycle, i.e. on a transition from
“0”
to “1”.
Tab. 8: Example of setting
the preset value
WARNING
Example of setting the preset value
Data word
1
2
Step 1
In
pu
t
Hex
0000
00AA
Bin
0000000000000000
0000000010101010
Dec
170
Comment: The encoder outputs the current position (00AAh) as
Input
.
O
ut
pu
t
Hex
0000
FFFF
Bin
0000000000000000
1111111111111111
Dec
65535
Comment: Bit 31 of the
output
is 0, the preset value (FFFFh) is not applied. The encoder
therefore continues to output the measured position 00AAh in step 2 that follows.
Step 2
In
pu
t
Hex
0000
00AA
Bin
0000000000000000
0000000010101010
Dec
170
O
ut
pu
t
Hex
8000
FFFF
Bin
1
000000000000000
1111111111111111
Dec
2147549183 (= 2
31
+65535)
Comment: Bit 31 of the
output
changes to 1, the preset (FFFFh) is applied and output in
step 3 as
input
.
Step 3
In
pu
t
Hex
0000
FFFF
Bin
0000000000000000
1111111111111111
Dec
65535
O
ut
pu
t
Hex
0000
FFFF
Bin
0000000000000000
1111111111111111
Dec
65535
Immediately after triggering the preset function, check whether there is a hazard from
the machine or system in which the encoder is integrated!
The preset function results in a change in the position value output by the encoder. This
change could cause an unexpected movement that may result in a hazard for persons or
damage to the system or other items.
