External Encoder (X14); Positioning On External Encoder (X14); Slip Compensation With External Encoder - SEW-Eurodrive IPOS plus Manual

6.4

External encoder (X14)

The following encoders can be connected to the MOVIDRIVE
on X14. To find out which encoder type your unit supports, refer to the system manual
or the operating instructions.
•
•
•
•
6.4.1

Positioning on external encoder (X14)

It makes sense to use an external encoder for positioning to compensate any connection
subject to slip or play between the drive and distance (for example, due to slipping
wheels or tooth backlash) or any mechanical play in gear unit backlash.
Table 1: Evaluation of the pulses of the external encoder
Incoming pulses (example)
Quadruple evaluation (fixed)
Scaling external encoder P944 (can be set)
Changing counter reading H510 ACTPOS. EXT
per encoder revolution
Once the control voltage has been switched on, if an AS1H or AV1H is used the absolute
value of this encoder is used as the actual position value of the external encoder H510.
For all other encoder types, H510 = 0 increments. The external encoder can be refer-
enced as the motor encoder (see the chapter "Reference Travel").
6.4.2

Slip compensation with external encoder

A trolley on wheels is run on rails. The carriage is moved by powering the wheels with a
gearmotor. The connection between the wheels and the rails is non-positive. This
causes slip between the rotational movement of the wheel and the resulting translational
movement of the carriage.
This means, for positioning using motor control it is essential that the position of the car-
riage is detected.
To do so, at startup the ratio of the increments of the motor encoder must be set to the
increments of the synchronous encoder. A description of these parameters with exam-
ples, and the procedure for setting them can be found in the descriptions of parameters
P944, P943 and P942 in the section "IPOS Parameters."
Manual – IPOSplus®
Position Detection and Positioning
®
Hiperface encoder type AS1H, ES1H or AV1H (only MOVIDRIVE
sin/cos encoder type ES1S, ES2S or EV1S (only MOVIDRIVE
5 V TTL sensor with DC 24 V voltage supply type ES1R, ES2R or EV1R
5 V TTL sensor with DC 5 V voltage supply type ES1T, ES2T or EV1T via option
DWI11
External encoder (X14)
®
A and B drive inverters
®
2048 2048
8192 8192
x 1 x 8
8192 65536
n
n
kVA
kVA
6
f
f
i
i
P Hz Hz
P
®
B or MCH)
B or MCH)
1024 1024
4096 4096
x 1 x 2
4096 8192
57