6-86
*How to obtain pulse data
The PG pulse data is incremented in B-phase forward (running forward) and decremented in A-phase
forward (running backward). Therefore, obtain the difference of data sampled this time and last time for
the t (ms) task, and add it for every t (ms) to calculate the pulse count value. As the pulse count value is
obtained by multiplying the encoder value by four, the formula is "4×encoder pulse count／revolution
".
Figure 6.5.8
*How to detect Z phase
The PG pulse can be obtained as mentioned above. However, with differences of the U62 "Position
detection (internal or PG(PD) input monitor" and U63 "Position detection (Z-phase input) (PG(PD)
monitor" within a task as PG_CNT and PG_CNT_Z respectively, the added data within the task period
(tms) is cleared to 0 by hardware Z-phase detection as shown in the figure below. By comparing each
memory within the next task, Z phase is detected if they do not match.
Figure 6.5.9
Note: Detection of the Z-phase standard position is enabled only when the OPC-VG1-PG (PD) option is
installed. If this PG is selected while this option is not installed or the o05 feedback pulse is
selected, the monitor data of U63 cannot be referenced.
32767
0
-32768
t: period
(SX task period)
32767
0
-32768
t: period
(SX task period)
T
T
When PG encoder runs forward
When PG encoder runs reverse
0
t: period (ms)
Task
When PG_CNT≠PG_CNT_Z, Z
phase is recognized by software.
Encoder Z phase
PG_CNT
PG_CNT_Z
When PG_CNT≠PG_CNT_Z,
Z phase is detected
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