ElmoMC SimplIQ Digital Servo Drives-Bell Command Reference - Manual (Page 218)

Position
command
d
dt
d
dt
HT[1]
HT[2] HT[3]
Σ
Current
command
PN[4] count/elect rev,
or PN[4]/4 count/step
Varying notch filter:
PF[16],PF[17]
Scale
Electrical angle command
Σ
AG[1]
AS[1]
-
RM
Σ
PN[5]
Figure 3-6: Torque and position reference in the open loop stepper mode
Note the following:
PN[4] sets the scale between the position command and the electrical angle rotation.
PN[4] may be viewed as the “micro-stepping ratio”: There are PN[4]/4 position counts
per step.
For open loop stepping of rotary motors, XM[2]-XM[1] must be an integer multiple
of PN[4], otherwise stepping angle jumps will appear on position modulo transitions.
HT[1] is the holding torque in Amp: the amount of current in the motor when its position
is steady.
HT[2] and HT[3] enable the insertion of extra torque to compensate for increased speed
and acceleration. The units of HT[2] are in Amp/(Count/Sec) and the units for HT[3] are
in Amp/(Count/Sec
2 ).
HT[2] and HT[3] are defined differently for open loop and closed loop stepper
control (see PN[9]).
SimplIQ for Steppers Application Note Unit Modes
MAN-STECR (Ver. 1.1)
19