Pleiger Elektronik
GmbH & Co. KG
Edition: 6/2007 Subject to modifications
Manual for 362MC
Page: 51
Display
The LED display of the controller always shows the value of the first input, that means the temperature
value
PT100-1
in
°C
in case of a PT100 sensor and the current value
4..20mA
in
%
in case of a current
sensor. The difference value can be displayed by means of the LCD display. To achieve this in the
menu
Display (5.8)
the parameterised input value (
ActValX, ActValU, Trend
) must be assigned to one of the
two lines of the LCD display.
For differential pressure control it is advantageous to scale the display to
bar
directly. For this the
parameter
Dim
must be set to
B
and
Scale-F
must be set to
6.0
. Both parameters reside in the
menu
Input (5.6)
. The parameter
Scale-0
stays unchanged
0.0
.
The difference value as well as the setpoint are than displayed on the LCD display in
bar
with one decimal
place. The step size for the input of the setpoint
Setp A
is
0,1 bar
and the range is
0,0 bar
to
6,0 bar
.
Appendix C4:
Functional extension - Differential actual value
The standard functions of the 362MC software can be extendet by additional software, which must be
installed at the factory. Necessary internal hardware extensions, such as extensions to memory areas,
etc. are installed at the same time.
The functional extension
difference input for actual values
described in this leaflet is installed in
controllers with Mat. Nr. 93620
3
xxxx and allows controlling the difference of two actual values, for example
in the case of differential pressure control of pumps.
Parameterisation
The difference of the actual values is calculated in two different ways. In addition to the standard inputs
PT100-1
or
4..20mA
,
PT100-2
,
Lin 4..
,
Lin 0..
or
Lin ..4
and
Resist
for the parameters
ActValX
,
ActValU
and
Trend
there are two more inputs
Diff_12
or
Diff_13
available in the
menu Input
.
Function of Diff_12
If this input is selected the difference of the actual values is always a temperature difference and is
calculated according to:
Diff_12
= (1
st
input PT100) - (2
nd
input PT100)
=
(PT100-1) - (PT100-2)
For this purpose the first input must be designed for temperature measurement using PT100 sensors in
the range of 0..200°C.
Function of Diff_13
If this input is selected the difference of the actual values is always a difference of current values and is
calculated according to:
Diff_13
= (1
st
input 4-20mA) - 2/3(3
rd
input 4-20mA) - 1/6
= (4..20mA) - 2/3(Lin 4..) - 1/6
For this purpose the first and the third input must be designed for 4..20mA current measurement. This
requires a hardware modification of the first input. The calculation of the difference is especially suited for
differential pressure measurement and requires pressure sensors designed for the following measuring
ranges:
Measurement input
Sensor
Measuring rang at
Comment
4 mA
20mA
1
st
analogue input
(4..20mA)
pressure side
0,0 bar
6,0 bar
Other sensors
3
rd
analogue input
(Lin 4..)
suction side
-1,0 bar
3,0 bar
are not useable.
