M O T I O N C O N T R O L P R O G R A M M I N G
DATA INPUT
AND OUTPUT
Motion Control Programming
105
delayed until a move has been completed (AM), an input sig-
nal changed states (AI), or by a pure time delay (WT).
The following example illustrates the use of trippoints in
executing a motion cycle.
Consider the motion cycle illustrated below. A forward
motion of 10,000 counts must start upon a pulse on input
#1. The initial velocity, acceleration, and deceleration
rates equal 20,000, 100,000, and 100,000 respectively.
After the motor has moved a distance of 6000 counts, the
controller starts a deceleration toward a speed of 10,000
counts/sec. That speed is maintained for the rest of the
move. Upon completion of the motion, the controller waits
100 milliseconds before returning the motor to the starting
position, at a speed of 20,000 counts/sec. Once there, the
controller is ready to repeat the cycle.
Notice that the scheduling of the various functions
requires the use of trippoints. The start of the motion is
delayed by the trippoint AI1. When the motion starts, the
velocity change is scheduled with the trippoint AD 6000.
The controller must then wait until the completion of the
move (AMX) and adds a pure delay of 100 ms (WT 100)
before returning the motor to the starting position. The
resulting flow chart is shown, and the instruction program
follows.
Instruction
Interpretation
#CYCLE
Label
PR 10000
Distance
SP 20000
Initial speed
AC 100000
Acceleration rate
DC 100000
Deceleration rate
AI1
Wait for start pulse
BGX
Start motion
AD 6000
Wait until X moved 6000 counts
SP 10000
Change the speed
AMX
Wait for completion of move
WT 100
Wait 100 msec
PR -10000
Reverse motion
SP 20000
Return speed
BGX
Start motion
AMX
Wait for end of motion
JP#CYCLE
Repeat the cycle
EN
End
Data Input and Output
Many applications require data to be input from an opera-
tor or messages to be displayed from the controller. For
easy operator interface, the DMC provides commands
that display messages and prompt the operator for data.
Messages can be sent to the host computer using the mes-
sage command, MG.
Sending a message. Example:
MG "The final value is", RESULT {F5.2}
The above statement sends the message "The final value
is" to the host computer. The value for the variable, RESULT,
is substituted with a format of 5 digits to the left of the deci-
mal and 2 to the right.
Operators are prompted to input data with the input
statement, IN, which contains a text message to prompt the
operator for the input data.
Prompt for data. Example:
IN "Input speed", SPX
The above statement sends the prompt "Input speed" to
the PC screen. The entered value is assigned to the vari-
able, SPX.
Cut to length. Example:
This program prompts the operator for the cut length. A
position move is then commanded. The encoder resolution is
4000 counts/inch.
Instruction
Interpretation
#BEGIN
Label
AC 800000
Specify acceleration
DC 800000
Specify deceleration
SP 5000
Specify speed
LENGTH = 3.4
Initial length in inches
#CUT
Cut routine
IN "Enter length", LENGTH
Prompt to enter length
PR LENGTH*4000
Specify position in counts
BG X
Begin motion
AM X
After motion complete
SB1
Set bit 1, turn on cutter
WT 100;CB1
Wait 100 msec, turn off cutter
JP #CUT
Repeat cut process
EN
End program
