Rockwell Automation 1398-PDM-xxx IQ Master Version 3.2.4 for IA-2000 and IQ-5000 Positioning Drive Modules, IQ-55 - Manual (Page 177)

Motion • Incremental (MOVD) and Absolute (MOVP) Motion 155
Publication 1398-PM601A-EN-P — October 2000
TUTORIAL
struct complex profiles. MOVD and MOVP commands can be in the application program or can be a
Host Language command. DV and DIF commands can only be used in the main body of the application
program.
PJOG is the position command generated by jogging motion. Jogging motion ramps up to a specified
velocity and then continues to run at that velocity until a new velocity is specified. Jogging motion can
be initiated by jog inputs, Host Language Commands, or MOVV instructions in the application pro-
gram.
PEXT, the third component of position command, comes from an external source. Encoder 2 may be
connected to an encoder or to a pulse and direction generator. The ULTRA Plus or IQ can be pro-
grammed to add the command from this source to the internally generated sources.
PCAM, the fourth component, is the position command generated by executing Cam Profiles. IQ Mas-
ter with Cam is an optional software program for creating complex electronic cam profiles. Refer to the
IQ-Series IQ-Cam Software Manual (Part Number 0013-1053-001).
In the remainder of this section, individual sources of motion will be discussed in greater detail fol-
lowed by a section about using combinations of these sources.
Incremental (MOVD) and Absolute (MOVP) Motion
MOVD and MOVP instructions are used to create incremental and absolute moves respectively. The
motion that results from these commands is a trapezoidal velocity move. The length of the move is
determined by a required argument of the instruction. The top velocity of the move is determined by an
optional argument in the instruction, by the setting of the velocity system variable, VEL, or by the
default velocity in parameters (in order of priority). The acceleration and deceleration rates for the move
are determined by the setting of the ACCEL variable or the default value in parameters (in order of pri-
ority).
If the values for velocity, acceleration, and move distance are conflicting, the move will be converted
from a trapezoidal velocity profile to a triangular profile with the ULTRA Plus or IQ calculating the
peak velocity. The resulting peak will be less than the one specified in this case.
ACCEL = 200 ;set the acceleration to 200
VEL = 20 ;set the velocity to 20
MOVD 6 ;Move 1 a distance of 6
MOVD = 1.8 ;Move 2 a distance of 1.8
In the example above, the commanded acceleration and velocity were equal, but the distances were dif-
ferent. In move 1, the peak velocity reached the specified velocity of 20. In move 2, the profile was
changed to a triangle with a peak velocity of less than 20. The acceleration rate of each move was the
specified value of 200. The distance was also the specified distance in each case.
Velocity
Velocity Velocity
Acceleration = 200
20
Acceleration
T1 T5 T6 T1 T2
Move 2 Move 1
T2 T3 T1 Time Time