Rockwell Automation 1398-PDM-xxx IQ Master Version 3.2.4 for IA-2000 and IQ-5000 Positioning Drive Modules, IQ-55 - Manual (Page 283)

Language Reference • Reference 261
Publication 1398-PM601A-EN-P — October 2000
WORDS
Sn: IF Scanned Event Scanned Event
Purpose The scanned event IF statement is used in the same way as a normal IF statement but is
preceded by Sn: , where n is a number from 1 to 8. These conditions are checked at
every step of the program. If the scanned event is enabled AND the condition is found
to be true, the specified action is taken.
Syntax Sn: IF condition action
n The number of the scanned event. There are eight scanned
events: n = 1, 2, 3, .... , 8.
condition The condition to be tested. The condition may be a comparison,
an input being ON or OFF, or a flag being ON or OFF.
Comparisons compare the values of two operands and deter-
mine if the condition is TRUE or FALSE. A comparison may be
greater than (>), less than (<), equal to ( = ), not equal to (<>),
less than or equal to (< = ), or greater than or equal to (> = ).
The operands of a comparison may be user variables, system
variables, analog input values (ADC), or constants.
I1 ON ;an input
F1 ON ;a user flag
INPOSN ;system flag
G1 > G2 ;comparison user variable
G1 > POS1 ;comparison system variable
POS2 <= 7.00 ;comparison constant
action The program statements in a scanned event routine can be any
legal program statement(s) except CALL, RETURN, JUMP,
MOVD, MOVP, DV, DIF, DELAY, DWELL, PRINT, READ,
ENABLE, and DISABLE statements. Multiple statements can
be enclosed in curly braces {}.
Remarks To detect a transition of an input with a scanned event, the keyword EDGE is used
with the IF statement. This will detect the transition of the input from OFF to ON,
rather than just the ON state. EDGE can only be used in a scanned event.
Scanned events are enabled in the program by Sn ON/OFF statements. Once a scanned
event has occurred, it will not be recognized again until the condition has gone false
and then true again or until another Sn ON statement is executed. Sn: routines must
be placed before the main body of a program after any ASSIGN or TITLE statements.
See Also Sn: TMRm, Sn ON/OFF/CONT
Example S1: IF I13 EDGE ON V11 = PCMD
S2: IF POS1 > = G10 04 = ON
S8: IF I5 ON
{IF I9 ON 03=ON
ELSE 03=OFF
}