62
Manual – IPOSplus®
6
SSI absolute encoder (DIP)
Position Detection and Positioning
6.5.7
6. Set Zero offset P954
Zero offset is used for assigning the value you want to a specific position. Enter the pa-
rameter as described for P954 in the chapter "IPOS Parameters".
6.5.8
7. Set encoder factors P942 and P943
The parameters are used for internal adaptation of the speed control and for monitoring
functions in the DIP11.
Practically, this adapts the physical quantity, a mechanical ratio between the motor en-
coder and external encoder and the mechanical feedrate constant (for example, for ex-
ternal incremental linear encoders).
The following diagram shows the connection between the parameters and variables.
To find out how to determine encoder factors, refer to the parameter descriptions for
P942/P943.
6.5.9
8. Set P941 actual position source
This parameter determines which position encoder is used for position control, provided
that an ”... & IPOS" operating mode has been set in P700 ”Operating mode".
There are positioning commands in the IPOS
plus®
program to control the motor con-
nected to MOVIDRIVE
®
. Set the Source actual position to "Absolute encoder DIP" if the
motor is to be positioned using the absolute encoder.
476717707
P
x
= Non-linearized position value of encoder
P
abs
= Actual position value for ramp generator and position controller
P941 = Actual position source
P942 = Encoder factor numerator
P943 = Encoder factor denominator
P953 = Position offset
P954 = Zero offset
P955 = Encoder scaling
H509 = External encoder with actual value on variable
H511 = Motor encoder with actual value on variable
ABS
P
act
P943
P955
P942
H511
P941
H509
DIP
P953
P954
INFORMATION
The circuit gain for position control of IPOS
plus®
, parameter P910 "Gain X controller"
was preset during startup of the speed control loop. This presetting means positioning
control is performed with the motor encoder. The difference in encoder resolution or
the time characteristics of the absolute encoder (e.g. laser distance measuring instru-
ment) may require a lower value setting.
P
i
f
kVA
Hz
n
P
i
f
kVA
Hz
n