Displaying the value of variables at the terminal
Variables may be sent to the screen using the format, variable=. For example, v1= , returns the value of the
variable v1.
Example - Using Variables for Joystick
The example below reads the voltage of an X-Y joystick and assigns it to variables vX and vY to drive the motors at
proportional velocities, where:
10 Volts = 3000 rpm = 200000 c/sec
Speed/Analog input = 200000/10 = 20000
#JOYSTIK Label
JG 0,0 Set in Jog mode
BGXY Begin Motion
#LOOP Loop
vX=@AN[1]*20000 Read joystick X
vY=@AN[2]*20000 Read joystick Y
JG vX,vY Jog at variable vX,vY
JP#LOOP Repeat
EN End
Operands
Operands allow motion or status parameters of the DMC-40x0 to be incorporated into programmable variables and
expressions. Most DMC commands have an equivalent operand - which are designated by adding an underscore (_)
prior to the DMC-40x0 command. The command reference indicates which commands have an associated operand.
Status commands such as Tell Position return actual values, whereas action commands such as KP or SP return the
values in the DMC-40x0 registers. The axis designation is required following the command.
Examples of Internal Variables:
POSX=_TPX Assigns value from Tell Position X to the variable POSX.
GAIN=_GNZ*2 Assigns value from GNZ multiplied by two to variable, GAIN.
JP #LOOP,_TEX>5 Jump to #LOOP if the position error of X is greater than 5
JP #ERROR,_TC=1 Jump to #ERROR if the error code equals 1.
Operands can be used in an expression and assigned to a programmable variable, but they cannot be assigned a
value. For example: _GNX=2 is invalid.
Special Operands (Keywords)
The DMC-40x0 provides a few additional operands which give access to internal variables that are not accessible by
standard DMC-40x0 commands.
Keyword Function
_BGn *Returns a 1 if motion on axis ‘n’ is complete, otherwise returns 0.
_BN *Returns serial # of the board.
_DA *Returns the number of arrays available
_DL *Returns the number of available labels for programming
_DM *Returns the available array memory
Chapter 7 Application Programming • 153 DMC-40x0 User Manual
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