2
0
2
0
-0
3
26
Communication with WCS read heads
Description of the protocol data
Activation of the read head
Data from read head
*) Speed information
The speed is binary coded in bits SP0 to SP6.
Diagnostic function F0=1
The read head can be requested to perform a diagnosis of the photoelectrics via the request
byte to the read head. For this purpose, the read head must be located outside of the code rail.
On the WCS2B and WCS3B read heads, the degree of dirt accumulation on the photoelectrics
is monitored automatically during operation and the diagnostic bit (DB) set if dirt accumulation
is too high. Thus the request for diagnosis to the read head via F0 in the request byte is no lon-
ger necessary. However, for reasons of downward compatibility, this function is also supported
by the new read heads.
F0
A1
A0
Read head address
x
0
0
Read head address 0
x
0
1
Read head address 1
x
1
0
Read head address 2
x
1
1
Read head address 3
0
x
x
Send position value
1
x
x
Send diagnosis result
Function number for read head F0=0 (send position value)
ERR
DB
OUT
SST
Description
State of the read
head lens
0
0
0
x
Current position value in P00 ... P18, binary
coded
Good
0
0
1
x
Read head outside the code rail, no position
value (see OUT message)
Good
0
1
0
x
Current position value in P00 ... P18, binary
coded
Poor
0
1
1
x
No position value, read head outside the code
rail (see OUT message)
Poor
1
x
x
x
No position value, error message from read
head, error number in P00 ... P04, binary
coded
-
x
x
x
1
Current speed unknown, last speed in
SP0 ... SP6 *)
-
x
x
x
0
Current speed in SP0 ... SP6 *)
-
SP0...SP6...
Speed in 0.1 m/s, binary coded
0:
Speed less than 0.1 m/s
126:
Speed more than 12.5 m/s
127:
Speed unknown
Example:
SP0...SP6...
1:
Speed 0.1 m/s
37:
Speed 3.7 m/s
112:
Speed 11.2 m/s