- - - - - - - - - - - - - - - - - - - - MELSEC·A
(b) A SET instruction is executed only at the leading edge of an input
condition to turn ON an annunciator.
The annunciator stays ON when the input condition is turned off.
When a number of annunciators are used, a SET instruction rather
than an OUT instruction is recommended to reduce scan time.
(2) Turning OFF an annunciator
An RST instruction (RST F[ ]) or LEOR instruction is used to turn OFF
(a) To turn OFF (reset) the annunciator which has been turned ON, use
an RST instruction (RST F[ ]).
(b) To turn OFF the annunciator which is stored in 09009 and 09125,
use an LEOR instruction.
An example program used to turn OFF an annunciator using an
LEOR instruction is shown in Fig. 4.23.
Circuit to turn OFF the
first one point
Kl I M9020
SET I FO
Circuit to turn ON an
SET I F255
r------1 - I
DUTY I KO I Kl I 09020
Timing clock is turned
used as the timing clock; ON for 1 scan and OFF for the next 1 scan
Fig. 4.23 Program to Turn OFF Annunciator
When an annunciator (F) is turned ON using an instruction other than OUT
and SET instructions, the annunciator has the same function as an internal
In this case, M9009 is not set; annunciator number is not stored in 09009,
09124 to 09132, either.
Setting is possible whether the ERROR LED should be
lit or blink when an annunciator Is turned
ON. For details, see Section 4.2.8.