Mitsubishi Electric MELSERVO-J5 Series User Manual page 217

■Backlash estimation servo parameter input
• Setting of gear ratio for backlash estimation
Input the numerator and denominator of the gear ratio on the gear connected to the servo motor. Inputting the numerator and
denominator of the gear ratio limits the travel distance during the backlash estimation to the minimum. When either the
numerator or the denominator of the gear ratio is set to "0", the travel distance during the backlash estimation is two rotations
each in the forward and reverse rotation side from the starting position of the backlash estimation.
Servo Symbol
parameter
PF66.0-3 BLG
PF66.4-7 BLG
■Gear diagnosis threshold setting method
The backlash threshold used in the gear failure prediction function can be set with [Pr. PF67 Backlash nominal value] and [Pr.
PF68 Backlash threshold multiplication], and is calculated by the following equation. When [Pr. PF68 Backlash threshold
multiplication] is set to "0", a value twice the value of [Pr. PF67 Backlash nominal value]/100 is set as the threshold.
Changing [Pr. PF68 Backlash threshold multiplication] from the initial value is not required. To change the backlash threshold
used for the gear failure prediction function, change [Pr. PF68 Backlash threshold multiplication].
Backlash threshold = [Pr. PF67 Backlash nominal value]/100 × [Pr. PF68 Backlash threshold multiplication]/10
Servo Symbol
parameter
PF67 BLN
PF68 BLTT
Name
Gear for backlash estimation -
Numerator
Gear for backlash estimation -
Denominator
Name
Backlash nominal value
Backlash threshold multiplication
Outline
Set the gear ratio numerator of the gear connected to the servo motor in
hexadecimal. If multiple gears are connected to the servo motor, set the gear ratio up
to where the load is applied.
If the gear ratio numerator and the denominator cannot be expressed by numbers up
16
to "2 -1", round up the gear ratio and set a value equal to or less than "2
both the numerator and the denominator.
[Pr. PF66.0-3 Gear for backlash estimation - Numerator] and [Pr. PF66.4-7 Gear for
backlash estimation - Denominator] do not affect the accuracy of the backlash
estimation even if they are shifted by a fraction.
Initial value: 0000h
Set the gear ratio denominator of the gear connected to the servo motor in
hexadecimal.
If multiple gears are connected to the servo motor, set the gear ratio up to where the
load is applied.
If the gear ratio numerator and the denominator cannot be expressed by numbers up
16
to "2 -1", round up the gear ratio and set a value equal to or less than "2
both the numerator and the denominator.
Initial value: 0000h
Outline
To set the threshold for gear failure prediction, a backlash nominal value must be set.
Input a backlash value presented by the manufacturer of the gear connected to the
servo motor.
When [Pr. PF66.0-3 Gear for backlash estimation - Numerator] or [Pr. PF66.4-7 Gear
for backlash estimation - Denominator] is set to "0", input the backlash nominal value
after converting the value into the rotation angle on the servo motor side.
When a value other than "0" is set in [Pr. PF66.0-3 Gear for backlash estimation -
Numerator] and [Pr. PF66.4-7 Gear for backlash estimation - Denominator], input a
value considering the gear ratio for backlash estimation.
When "0" is set, even if backlash estimation is performed, [AL. 0F7 Machine
diagnosis warning] does not generate.
Initial setting: 0.00 [degree]
Set the threshold multiplication that will be used for setting the threshold for gear
failure prediction. The threshold used for gear failure prediction is as follows.
Backlash threshold = [Pr. PF67 Backlash nominal value]/100 × [Pr. PF68 Backlash
threshold multiplication]/10
When "0" is set, a value twice the value of [Pr. PF67 Backlash nominal value]/100 is
set as the backlash threshold.
When the backlash threshold is "0", even when the backlash estimation is performed,
[AL. 0F7 Machine diagnosis warning] will not be outputted.
Initial setting: 0
16
-1" for
16
-1" for
4 APPLICABLE FUNCTIONS
4.5 Machine diagnosis
4
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