Omron SYSMAC CJ Operation Manual page 289

How-to's
Example 8
Opposite to the P_GAIN, where the higher, the better (the limit is when the
mechanical system starts vibrating), for the VFF_GAIN there is an optimum
value (the one in test 6), values higher than this value has an error
proportional to the speed/acceleration but with different sign. The required
correction is too large.
The parameter values for the example are:
/i
Motion Parameter values
P_Gain=131072
VFF_GAIN=1650000
Fn001=6
Section 5-1
277