Galil DMC-3425 user manual Automatic Subroutines for Monitoring Conditions, Example - Limit Switch

Automatic Subroutines for Monitoring Conditions

Often it is desirable to monitor certain conditions continuously without tying up the host or DMC-3425 program sequences. The DMC-3425 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, and having an application program actively executing on the controller. 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
#TCPERR	Ethernet Communication Error

The following examples illustrate the use of the automatic subroutines:

Example - Limit Switch:

This simple program prints a message upon the occurrence of a limit switch. For the #LIMSWI sub- routine to execute, the DMC-3425 must be executing an applications program from memory and the controller must be commanding the motor to move. The RE command is used to return from the #LIMSWI subroutine. The #LIMSWI subroutine will be re-executed if the limit switch remains active.

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

Example - Position Error

Instruction		Interpretation
:ED		Edit Mode
000	#LOOP	Dummy Program
001 JP #LOOP;EN		Loop
002	#POSERR	Position Error Routine
003	V1=_TEA	Read Position Error
004 MG "EXCESS POSITION ERROR"		Print Message
005 MG "ERROR=",V1=		Print Error
006	RE	Return from Error
<control> Q		Quit Edit Mode
:XQ #LOOP		Execute Dummy Program
:JG 100000		Jog at High Speed
:BGA		Begin Motion

124 • Chapter 7 Application Programming DMC-3425