Vega VEGAMET 391, Руководство по эксплуатации, Страница: 44 / 68

l
D
igital input
4
- R
elay
4
I
f the pump monitoring for a relay was switched on
,
a timer is started
when the relay is switched on
(
time allowance with parameter
"
R eport
time
"
). I
f the checkback signal comes from the pump on the respective
digital input within the de
fi
ned report time
,
the pump relay remains
energized
,
otherwise the relay is immediately switched o
ff
and a fault
signal outputted
. A
fault signal and switching o
ff
of the relay is carried
out even if the relay is already switched on and the pump checkback
signal changes during the running time of the pump
. I
n addition
,
a
switched o
ff
relay of the pump control is looked for and switched on
instead of the disturbed relay
. A L
ow signal on the digital input is
processed as a pump error signal
. T
o reset a pump control
,
you can
execute the pump failure reset for the respective relay in the menu
" E xtended settings - R eset " .
S
witch on reaction of the pump control 2
A
fter the signal conditioning instrument is switched on
,
the relays are
still in switched
-
o
ff
condition
. D
epending on the input signal and the
switch
-
on period of the individual relays
,
the following relay switching
conditions can occur after the start procedure
:
l
I
nput signal is higher than the upper switching point
- > R
elay with
the shortest switch on period is switched on
l
I
nput signal is between lower and upper switching point
-
>
R
elay
remains switched o
ff
l
I
nput signal is smaller than the lower switching point
-
>
R
elay
remains switched o
ff
8 . 3 P ump control 3 / 4 ( sequentially controlled )
P
ump control
3
/
4
is used to control several pumps with the same
function alternately and in a
fi
xed sequence
. I
n case of an increased
requirement
,
all pumps can run at the same time depending on the
entered switching points
. W
ith this measure
,
a steady utilization of the
pumps is reached and the reliability increased
.
A
ll relays with activated pump control are not assigned to a certain
switching point but are switched on and o
ff
alternately
. T
he signal
conditioning instrument selects when reaching a switching on point
,
the relay which is next in the sequence
. W
hen reaching a switching o
ff
point
,
the relays are switched o
ff
in the sequence they were switched
on
.
P
robable failures of the pumps can be processed in addition via the
digital inputs
.
W
ith this pump control
,
there are two di
ff
erent versions
:
l
P
ump control
3
: T
he upper switching point determines the switch
-
o
ff
point for the relay
,
whereas the lower switching point
determines the switch
-
on point
l
P
ump control 4
: T
he upper switching point determines the switch
-
on point for the relay
,
whereas the lower switching point
determines the switch
-
o
ff
point
F unctional principle
44
VEGAMET
391
•
4
…
20
m
A / HART
signal conditioning instrument
8
A
pplication examples
36032
-
EN
-
091116