Ascon Tecnologic - K31D - OPERATING INSTRUCTIONS - PAG. 6
Again in the
]
PAn
group is present the parameter
AdE
that
defines the 3 LEDs shift index (
) functioning.
The lighting up of the green LED (=) indicates that the
process value is within the range [
SP
+
AdE
÷
SP
-
AdE
], the
lighting up of the LED
(-) indicates that the process value
is lower than [
SP
-
AdE
] and the lighting up of the LED
(+)
indicates that the process value is higher than [
SP
+
AdE
].
5.2 Output Configuration
The instrument outputs can be programmed by entering the
group of parameters
]
Out
, where the relative parameters
o1F
,
o2F
,
o3F
and
o4F
(depending on the number of out-
puts available on the instrument) are located.
The outputs can be set for the following functions:
1.rEG
Main control output;
2.rEG
Secondary control output;
ALno
Alarm output normally open (NO);
ALnc
Alarm output normally closed (NC);
ALni
Alarm output NC with LED reverse indication;
oFF
Output deactivated.
The coupling between output-number – alarm-number can
be made in each alarm group referred to each alarm (
]
AL1
,
]
AL2
or
]
AL3
).
If the instrument has an analogue control output, the type of
output can be selected using the Aot parameter in the group]
InP with the following possibilities:
0-20
0 ÷ 20 mA;
4-20
4 ÷ 20 mA;
0-10
0 ÷ 10 V;
2-10
2 ÷ 10 V.
5.3 Absolute or Differential Temperature
Controller
Through the
PrrG
parameter it is possible to set the process
variable used by the controller to operate.
In fact the controller can operate considering the process
variable as the value measured at
Input 1
(
Pr1
), the value
measured at
Input 2
(
Pr2
), the difference between the two
inputs
Pr1-Pr2
(
P1-2
) or can consider the difference be-
tween the two inputs
Pr1-Pr2
but with a maximum limit and a
minimum limit for the
Pr2
measurement (
P1-L
).
The choices
PrrG
=
P1-2
or =
P1-L
make the controller
operate as a differential controller.
In these cases the controller acts on the control outputs so it
keeps the difference
Pr1-Pr2
equal to the Set Point value.
The difference between the two modes lies in the fact that
the
P1-L
mode activates a limit in the controller in terms of
the calculation of the temperature difference according to the
P2HL
and
P2LL
parameters (both in the
]
SP
group) so that:
If
Pr2 > P2HL
the process value considered by the controller is
[
Pr1-P2HL
]
If
Pr2 < P2HL
the process value considered by the controller is
[
Pr1-P2LL
]
When
P2HL
and
P2LL
thresholds are exceeded by
Pr2
tem-
perature, a control takes place as if the
Pr2
temperature is
the value of the limit regardless of the value actually read.
The aim of this function is to limit the differential regulation to
within a maximum range of the
Pr2
measurement.
With the differential control the working mode
Func
=
CooL
is used for applications with which the action of the actuator
reduces the
Pr1-Pr2
difference (thus countering the
Pr1-Pr2
difference that naturally tends to increase).
Viceversa the
Func
=
HEAt
mode is used for applications
with which the action of the actuator increases the
Pr1-Pr2
difference thus countering the
Pr1-Pr2
difference that natu-
rally tends to decrease).
Obviously the
Neutral Zone
mode or the
Double action
mode will set
OFF
both actions.
HSEt
Func
=
Cool
off
off
off
ON
ON
ON
Temp.
time
Pr1
Pr1- Pr2
Pr2
SP1
SP1 + HSEt
SP1
1.rEG
Example of differential
ON/OFF
control (
On.FA
) with
Func
=
CooL
.
m
The controller is already programmed in production to
carry out differential regulation and display the tem-
perature difference
Pr1
-
Pr2
.
5.4 ON/OFF Control (
1.rEG
)
All the parameters referring to the
ON/OFF
control are con-
tained in the group
]
rEG
.
This type of control can be obtained by programming pa-
rameter
Cont
=
On.FS
or =
On.FA
and works on the output
programmed as
1.rEG
, depending on the process value set
with
PrrG
, on the active Set Point
SP
, on the functioning
mode
Func
and on the hysteresis
HSEt
.
The instrument carries out an
ON/OFF
control with symmet-
ric hysteresis if
Cont
=
On.FS
or with asymmetrical hyster-
esis if
Cont
=
On.Fa
.
HEAt
-
on.FS
OUT
1.rEG
SP
PV
HSEt
HSEt
HEAt
-
on.FA
OUT
1.rEG
SP
PV
HSEt
time
off
off
C oo L
-
o n .FS
OUT
1.rEG
SP
PV
HSEt
HSEt
C oo l
-
o n .FA
OUT
1.rEG
SP
PV
HSEt
time
time
time
ON
ON
ON
off
off
ON
ON
ON
off
off
ON
ON
ON
off
off
ON
ON
ON
The control works in the following way: in the case of reverse
action, or heating (
FunC
=
HEAt
), it deactivates the output,
when the process value reaches [
SP
+
HSEt
] in case of sym-
metrical hysteresis, or [
SP
] in case of asymmetrical hystere-
sis and is then activated again when the process value goes
below value [
SP
-
HSEt
].
Viceversa, in case of direct action, or cooling (
Func
=
CooL
),
it deactivates the output, when the process value reaches
[
SP
-
HSEt
] in case of symmetrical hysteresis, or [
SP
] in case
of asymmetrical hysteresis and is activated again when the
process value goes above value [
SP
+
HSEt
].
