Lenze S94P01G Position Servo - Manual (Page 57)

S94P01G
55
Operation
6.3 Position Mode Operation (gearing)
In position mode the drive will follow the master reference signals at the 1-4 inputs of
P3. The distance the motor shaft rotates per each master pulse is established by the
ratio of the master signal pulses to motor encoder pulses (in single loop configuration).
The ratio is set by “System to Master ratio” parameter (see section 5.3.16).
Example 1
Problem: Setup the drive to follow a master encoder output where 1 revolution of
the master encoder results in 1 revolution of the motor
Given: Master encoder: 4000 pulses / revolution (post quadrature)
Motor encoder: 8000 pulses / revolution (post quadrature)
Solution: Ratio of System (motor encoder) to Master Encoder is 8000/4000 = 2/1
Set parameter “System to master ratio” to 2:1
Example 2
Problem: Setup drive so motor can follow a master encoder wheel where 1
revolution of the master encoder results in 3 revolutions of the motor
Given: Motor encoder: 4000 pulses / revolution (post quadrature)
Master encoder: 1000 pulses / revolution (post quadrature).
Desired “gear ratio” is 3:1
Solution: Ratio is motor encoder PPR divided by master encoder PPR times the
“gear ratio”:
(Motor PPR / Master PPR)*(3/1) => (4000/1000)*(3/1) => 12/1
Set parameter “System to master ratio” to 12:1
6.4 Dual-loop Feedback
In dual-loop operation (position mode only) the relationship between the Master input
and mechanical system movement requires that two parameters be set:
1. “System to master ratio” sets the ratio between the second encoder pulses (system
encoder) and the master input pulses.
2. “Prime to second encoder ratio” sets the ratio between the second and primary
(motor) encoder. If the motor is equipped with a resolver connected to the resolver
option module, the primary encoder resolution of 65536 (post quadrature) must
be used.
When operating in this mode the second encoder input is applied to integral portion of
the position compensator. Therefore it is important that the Position I-gain and Position
I-limit parameters are set to non 0 values. Always start from very small values of Position
I-limit values.
Note
When using an encoder-based drive and operating with the Resolver
Option Module as the primary feedback, a second encoder can be
connected to P4.