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6.2 Rotary inertia presumption 
6.2.1 Overview 
Rotational inertia estimation is the function of automatic operation (forward and reverse) in the driver 
and estimate the load inertia in operation. 
Rotational inertia ratio (the ratio of load inertia to motor rotor inertia) is a benchmark parameter for 
gain adjustment, and it must be set to the correct value as far as possible. 
6.2.2 Notes 
Occasions where inertia cannot be presumed 
  Mechanical systems can only operate in one direction 
The occasion where inertia presumption is easy to fail 
  Excessive load moment of inertia 
  The running range is narrow and the travel is less than 0.5 circles. 
  The moment of inertia varies greatly during operation. 
  Mechanical rigidity is low and vibration occurs when inertia is presumed. 
Notes of Inertia Presumption 
  Since  both directions  are rotatable within  the  set range  of  movement, please  confirm  the 
range or direction of movement; and ensure that the load runs in a safe journey. 
  If the presumed inertia under default parameters runs jitter, indicating that the present load 
inertia is too large, please switch to large inertia mode (P2-03.3=1) and operate again. It is 
also possible to set the initial inertia to about twice the current one and execute again under 
larger loads. 
  Driver inertia ratio recognition upper limit is 200 times (parameter upper limit is 20000). If 
the estimated inertia ratio is exactly 20000,  it means that the inertia ratio has reached the 
upper limit and can not be used, please replace the motor with larger rotor inertia. 
Other notes 
  At present, the  inertia switching function is not  supported, and the second  inertia ratio is 
invalid. 
  The inertia ratio upper limit changes to 500 times for the driver firmware 3700 and higher 
version (parameter upper limit value is 50000). 
6.2.3 Operation tool 
The presumptive tools of load moment of inertia are driver panel and XinjeServo software. 
Driver firmware needs 3700 and higher version   
All versions of software supported   
Note: driver firmware version can be checked through U2-07.