Siemens 353, Руководство пользователя, Страница: 94 / 246

Function Blocks UM353-1B
April 2012 3-64
3.2.62 OST_ - One Shot Timer
OST_ function blocks provide a high (1) output for a
predetermined time, set by ON TIME, when input P goes
high (1). If input P goes low (0), the output will remain
high until the time expires. If input P goes high during the
on time, the elapsed timer will be re-triggered if RETRIG
is set to YES.
ON TIME is adjustable over the full range of the display
which is 0.00000 to 999999. If the delay time is set to
less than the scan time of the station the delay time will
equal the scan time.
Output ET (elapsed time) will ramp from 0.0 to the value
of ON TIME and remain there until P goes low (0). Output RT (remaining time) equals ON TIME - ET.
POWER UP - During a warm start, when PU LAST is set to YES, the block will initialize at the input/output states
and elapsed time in effect at the instant power down occurred. A cold start will initialize the input/output states and
elapsed time to 0.
P ulse Input
ONE SHOT TIMER
O1
O utput 1
ONE SHOT TIMER
OST_ ESN = 000
P
E S N
E xec. S eq. N o.
(H)
................. 001 to 250
P
T
U P
N
I
INPUT P
(H)
........... loop tag.block tag.output ( null )
M E I O N T
ON TIME (minutes)
(S)
.................... Real (0.0)
P ower U p LAST
(S)
................... NO/YES (YES)
P U L A S T
ET
E lapsed T ime
RETRIG ger on new pulse
(S)
.... NO/YES (YES)
G I R T E R
RT R emaining T ime
BLOCK DIAGRAM
O1
P
O1
P
RETRIG = YES
.
.
ET
0
1
0.0
0
1
ON TIME
ET
RT