Motor Gear Ratio Setting Function; Position Biasing Function; Speed Biasing Function - Hitachi SJ700-2 Instruction Manual

4.3.8 Motor gear ratio setting function

The motor gear ratio setting function allows you to make the
inverter effectively control a specific machine in which an encoder
is installed at the opposite end of the motor.
Specify the actual pulse count of the encoder as the encoder pulse-per-revolution (PPR) setting (P011).
Specify the ratio of the motor speed to the encoder speed as the motor gear ratio (numerator "P028" and
denominator "P029").
According to the above settings, the encoder pulse-per-revolution (PPR) setting data converted into motor
shaft data is set in the inverter.
The encoder pulse-per-revolution (PPR) setting data converted into motor shaft data is used to detect
speeds and positions. The data specified as the encoder pulse-per-revolution (PPR) setting (P011) is
used to calculate the home search stop position.
Item
Numerator of the motor gear ratio
Denominator of the motor gear ratio
Encoder pulse-per-revolution (PPR)
setting
Note 1: The motor gear ratio (N/D) must be within the following range:
1/50 ≤ N/D ≤ 20
N: Numerator of the motor gear ratio
D: Denominator of the motor gear ratio
<Example of use>
Encoder
(1,024 pulses)
If the ratio of the motor speed to the encoder speed is 1:10, set the following data:
Encoder pulse-per-revolution (PPR) setting (P011): 1024
Numerator of the motor gear ratio (P028): 10
Denominator of the motor gear ratio (P029): 100
In this case, the periphery of the encoder shaft is divided into 4,096 sections to determine the points for
home search. Note that the conceptual layout of the home search stop position is inverted from that
shown in Figure 7-2.

4.3.9 Position biasing function

- The position biasing function allows you to make the position
command bias during operation in pulse train position control
mode. This function adds the specified number of pulses to the variation of position data every 2 ms.
Use this function to adjust the phase of the synchronization point during synchronous operation.
- Specify the quantity to be added as the position bias quantity (P024).

4.3.10 Speed biasing function

- This function allows you to make the speed command bias
during operation in pulse train position control mode.
- Specify the bias quantity for the additional-frequency setting (A145), and select a sign through
additional-frequency sign selection (A146).
- Assign function "50" (ADD) to an intelligent input terminal. The speed command is biased by the
specified quantity while the ADD terminal is on.
Variation of position
command
Variation of position
feedback data
Function code
P028
P029
128. to 9999., 1000 to 6553
P011
(10000 to 65530) (pulses)
Gear/load
Motor
(1:10)
Position biasing
P024
terminal
Position control
4 - 105
Chapter 4 Explanation of Functions
Related code
P028: Numerator of the motor gear ratio
P029: Denominator of the motor gear ratio
P011: Encoder pulse-per-revolution (PPR)
setting
Range of data
0. to 9999
0. to 9999
Related code
P024: Position bias quantity
Related code
A145: Additional-frequency setting
A146: Additional-frequency sign selection
Speed biasing
A145
ADD
Selected by A146
+/-
Speed control
Speed feedback data
Description
Setting of the ratio of motor
speed to encoder speed
Setting of the actual pulse
count of encoder