Technical Manual
WDGA with EtherCAT
4 - EtherCAT
© Wachendorff Automation GmbH & Co. KG
37
Rev.1.09
As can be seen from the above, value 89h defines that the cam switch positions CAM
1, CAM 4 and CAM 8 are high and the remaining cams are low. When the shaft turns
further, it could happen that ultimately CAM 4 also becomes low. In this case, the value
of the CAM state register = 81h:
Position
7(MSB) 6
5
4
3
2
1
0(LSB)
Type
CAM 8 CAM 7 CAM 6 CAM 5 CAM 4 CAM 3 CAM 2 CAM 1
Value
1
0
0
0
0
0
0
1
Logic
High
Low
Low
Low
Low
Low
Low
High
Table 4.31: CAM state register - value 81h
The independent switching of each individual CAM means that different states can be
created within an object and sub-indices 256 that can be used to control machines.
4.3.4.14
6301h
– CAM enable register
Every cam switch position of the CAM channel in the encoder must be "engaged"
individually for use. The individual CAMs are "engaged" by writing the appropriate
value into object 6301h sub-index 01h. The correct value can be found by setting the
bit for each cam switch position that is supposed to be active to 1 in binary notation. If
only CAM 2, CAM 4 and CAM 7 are supposed to be active, for example, then according
to the binary notation:
Position
7(MSB) 6
5
4
3
2
1
0(LSB)
Type
CAM 8 CAM 7 CAM 6 CAM 5 CAM 4 CAM 3 CAM 2 CAM 1
Value
0
1
0
0
1
0
1
0
Table 4.32: CAM enable register - value 4Ah
This corresponds to the value 4Ah. If this is written into object 6301h sub-index 01h,
only the cam switch positions CAM 2, CAM 4 and CAM 7 are active and able to change
depending on their configuration.
4.3.4.15
6302h
– CAM polarity register
The CAM polarity register in object 6302h sub-index 01h allows the polarities of every
cam switch position in the CAM channel to be changed. By default, the polarity is set
so that all cam switch positions "jump" to high (= 1b) when their position values are at
their limits (default = 00000000b = 00h). By changing the individual bits, the individual
polarities of the cam positions can be changed. This means that, at a value of 13h (=
00010011b), CAM 1, CAM 2 and CAM 6 are inverted (bit = 0b (low) if the position value
is within the limits).
Position
7(MSB) 6
5
4
3
2
1
0(LSB)
Type
CAM 8
CAM 7
CAM 6
CAM 5
CAM 4
CAM 3
CAM 2
CAM 1
Value
0
0
0
1
0
0
1
1
Logic
Default Default Default Inverted Default Default Inverted Inverted
Table 4.33: Example of the CAM polarity register
Summary of Contents for WDGA 58A
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