DMC-1500 Chapter 7 Application Programming • 95
Auto-Start Routine
The DMC-1500 has a special label for automatic program execution. A program which has been
saved into the controllers non-volatile memory can be automatically executed upon power up or reset
by beginning the program with the label #AUTO. The program must be saved into non-volatile
memory using the command, BP.
Automatic Subroutines for Monitoring Conditions
Often it is desirable to monitor certain conditions continuously without tying up the host or DMC-
1500 program sequences. The DMC-1500 can monitor several important conditions in the
background. These conditions include checking for the occurrence of a limit switch, a defined input,
position error, or a command error. Automatic monitoring is enabled by inserting a special, predefined
label in the applications program. The pre-defined labels are:
SUBROUTINE DESCRIPTION
#LIMSWI Limit switch on any axis goes low
#ININT Input specified by II goes low
#POSERR Position error exceeds limit specified by ER
#MCTIME Motion Complete timeout occurred. Timeout period set by TW command
#CMDERR Bad command given
#COMINT Communication Interrupt Routine
For example, the #POSERR subroutine will automatically be executed when any axis exceeds its
position error limit. The commands in the #POSERR subroutine could decode which axis is in error
and take the appropriate action. In another example, the #ININT label could be used to designate an
input interrupt subroutine. When the specified input occurs, the program will be executed
automatically.
NOTE: An application program must be running for automatic monitoring to function.
Example - Limit Switch
This program prints a message upon the occurrence of a limit switch. Note, for the #LIMSWI routine
to function, the DMC-1500 must be executing an applications program from memory. This can be a
very simple program that does nothing but loop on a statement, such as #LOOP;JP #LOOP;EN.
Motion commands, such as JG 5000 can still be sent from the PC even while the "dummy"
applications program is being executed.
Instruction Interpretation
#LOOP Dummy Program
JP #LOOP;EN Jump to Loop
#LIMSWI Limit Switch Label
MG "LIMIT OCCURRED" Print Message
RE Return to main program
XQ #LOOP Execute Dummy Program
JG 5000 Jog X axis at rate of 5000 counts / sec
BGX Begin motion on X axis
Now, when a forward limit switch occurs on the X axis, the #LIMSWI subroutine will be executed.
NOTE: The RE command is used to return from the #LIMSWI subroutine.
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