Emerson FM-3 User Manual
Page 72
58
FM-3 Programming Module Reference Manual
Time Constant
Position Error Integral is a control term, which can be used to compensate for the continuous
torque required to hold a vertical load against gravity. It is also useful in low speed
applications, which have high friction.
The user configures this control term using the “Position Error Integral Time Constant”
parameter. This parameter determines how quickly the drive will correct for in-position
following error. The time constant is in milliseconds and defines how long it will take to
decrease the following error to 37 percent of the original value. In certain circumstances the
value actually used by the drive will be greater than the value specified here.
Min Time Constant = 1000/Response
For example, with “Response” set to 50, the minimum time constant value is 1000/50 = 20
msec.