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. 936203xxxx 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.
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