ABB ACSM1 - Page 76

Drive control and features
76
t
1
: Rising edge of encoder DI2 signal (proximity switch signal) is detected when the
master position is 0°. The follower position is -130° (stored to signal 4.04 PROBE2
POS MEAS).
t
2
: Rising edge of encoder DI1 signal (proximity switch signal) is detected when the
follower position is 0°. The actual position of the encoder is -30° (stored to signal
4.03 PROBE1 POS MEAS). Distance between the follower position and the actual
position is 0° - (-30°) = 30°.
According to parameter 62.16 PROBE1 POS and 62.18 PROBE2 POS settings the
follower should be 120° behind the master.
The following phase shift between the master and follower is calculated and stored
as reference error 4.05 CYCLIC POS ERR.
(62.18 PROBE2 POS - 4.04 PROBE2 POS MEAS) - (62.16 PROBE1 POS - 4.03
PROBE1 POS MEAS) = [-120° - (-130°)] - [0° - (-30°)] = -20°
t
3
: Error has been corrected and the follower is 120° behind the master. Cyclic
function is ready for a new correction if necessary.
Note 1: Only after the active correction is finished is the next position latching
enabled.
Note 2: The cyclic corrections are always performed along the shortest path. This
must be taken into account in all rollover applications.
Note 3: In rollover applications, the correction range is limited to ±180°.
t
1
t
2
t
1
t
2
-130
-30
-20
0
x
°
-130°
30
360 = 0
x
° - 120°
0°
-30°
t
3
t
3
340
-100°
x°
x° - 120°
DI1
DI2
DI2
DI1
DI2
DI1
0°
0°
-100°
4.03 PROBE1 POS MEAS
4.05 CYCLIC POS ERR
4.18 SYNC ERROR
1.12 POS ACT
MASTER
CYC POS ACT ERR
4.04 PROBE2 POS MEAS
Encoder DI1
Encoder DI2
4.16 SYNC REF GEARED
MASTER FOLLOWER
FOLLOWER