Reference Manual

PMAC 2 Software Reference
PMAC I-Variable Specification 95
Ix60 Motor x Servo Cycle Period Extension
Range
0 .. 8,388,607
Units
Servo Interrupt Periods
Default
0
Remarks
Ix60 permits an extension of the servo update time for Motor x beyond the servo interrupt
period, which is controlled by hardware (E3-E6, E29-E33, E98, and master clock). The
servo loop will be closed every (Ix60 + 1) servo interrupts. With the default value of zero,
the loop will be closed every servo interrupt. For the standard PID servo algorithm, Ix60
must be set to a value that can be expressed as (2
n
– 1), where “n” is a non-negative
integer.
Other update times, including trajectory update and phase update are not affected by Ix60.
I10 does not need to be changed with Ix60.
The velocity values reported for a motor with the V or <CTRL-V> command, and the
actual velocity registers in regular memory or DPRAM, are affected by Ix60. They are
reported in counts per servo loop closure, not counts per servo interrupt.
See Also
Servo Update Rate (Closing the Servo Loop)
On-line commands <CTRL-V>, V
M-Variable Mx66
Jumpers E3-E6, E29-E33, E98; I10.
Ix61 Motor x Current Loop Integral Gain {PMAC2 only}
Range
0.0 .. 1.0 (24-bit resolution)
Units
Output = 8 * Ix61 * Sum [i=0 to n] (Icmd[i]-Iact[i])
Default
0
Remarks
Ix61 is the integral gain term of the digital current loops, multiplying the difference
between the commanded and actual current levels and adding the result into a running
integrator that adds into the command output. It is only used if Ix82>0 to activate digital
current loop execution.
Ix61 can be used with either Ix62 forward-path proportional gain, or Ix76 back-path
proportional gain. If used with Ix62, the value can be quite low, because Ix62 provides the
quick response, and Ix61 just needs to correct for biases. If used with Ix76, Ix61 is the
only gain that responds directly to command changes, and it must be significantly higher to
respond quickly.
Ix61 is typically set using the current loop auto-tuner or interactive tuner in the PMAC
Executive Program. Typical values of Ix61 are 0.02.
See Also
Setting Up PMAC Commutation
I-variables Ix62, Ix66, Ix76, Ix82