#3006 just pauses execution which can be re-started by pressing CYCLE START again.
#3000 generates alarm condition and terminates execution.
More information (copied from Macro book by Sinha):
Macro Alarms
Alarm refers to an error condition that terminates the execution of the
current operation. Pressing the MESSAGE key on the MDI panel
shows the error message. The alarm condition may arise due to a
number of reasons, including hardware problems with the machine.
Further operation on the machine is possible only after rectifying the
problem, and then pressing the RESET key. A syntax error in the program,
out of range values, illegal data entry, etc. are software-related
error conditions. CNC automatically issues an alarm in such cases.
There are, however, situations when the control will not sense the
error, even though the program execution must be terminated. For
example, a probing system installed on the machine may detect tool
breakage, necessitating immediate termination of program execution,
though the control will not recognize this problem. To tackle such
cases, provision also has been made to issue user-generated alarms,
which are called macro alarms.
When a value from 0 to 200 is assigned to system variable #3000,
the machine stops with the alarm message, “MACRO ALARM.” The
displayed alarm number is 3000 plus the number assigned to it. Thus
#3000 = 1; would terminate the current operation, and display “3001
MACRO ALARM” when the MESSAGE key is pressed.
It is also possible to display a user-specified message up to 26
characters as alarm message by typing it within parentheses, after the
assigned value for variable #3000.
Example:
#3000 = 1 (TOOL BROKEN);
that would display “3001 TOOL BROKEN” on the message screen.
Execution Pause
System variable #3000 generates an alarm condition and terminates
the program execution, whereas variable #3006 causes temporary
pause of execution, which can be restarted by pressing the CYCLE
START button again. In the paused state, pressing the MESSAGE key
displays the user-specified message (up to 26 characters). Assigning a
number to variable #3006 halts the program execution. There is no
significance to this number, because message number is not displayed.
So, normally, 1 is assigned. Example:
#3006 = 1 (CHECK THE DIAMETER);
This would temporarily stop the execution, and display “CHECK
THE DIAMETER” on the message screen. If no message is typed,
nothing would be displayed.
