Liquiline CM44P Operation
Endress+Hauser 125
Menu/Setup/Additional functions/Mathematical functions/MF1 to 8/Mode = Formula
Function Options Info
Result unit Free text You may enter a unit for the calculated value if
desired.
Result format Selection
• #
• #.#
• #.##
• #.###
• #.####
Factory setting
#.##
Select the number of decimal places.
Result numeric Read only Current, calculated value
Mathematical function
assignment view
Overview of the configured functions
Example: 2-point chlorine regulator with volume flow monitoring
A relay output activates a dosing pump. The pump should switch on when the following 3
conditions are met:
• (1) There is flow
• (2) The volume flow is above a defined value
• (3) The concentration of chlorine drops below a defined value
1. Connect a binary input signal from an "INS" point level switch of the CCA250
assembly to the DIO module.
2. Connect an analog input signal of a volume flow meter to the AI module.
3. Connect the chlorine sensor.
4. Configure the Formula mathematical function: Source A = binary input DIO, Source
B = current input AI, Source C = Input Disinfection.
Formula:
A AND (B > 3) AND (C < 0.9)
(where 3 is the lower limit value of the volume flow and 0.9 is the lower limit
value of the chlorine concentration)
5. Configure the relay output with the Formula mathematical function and connect the
dosing pump to the corresponding relay.
The pump is switched on if all 3 conditions are met. If one of the conditions is no longer
met, the pump is switched off again.
Instead of outputting the result of the formula directly to a relay, you can also connect a
limit switch in between in order to attenuate the output signal via a switch-on and switch-
off delay.
Example: Load-based control
The load - i.e. the product of the concentration and volume flow - is needed for the dosage
of precipitants, for instance.
1. Connect the input signal of a phosphate analyzer to the AI module.
2. Connect an analog input signal of a volume flow meter to the AI module.
3. Configure the Formula mathematical function: Source A = Input signal phosphate
and Source B = Input signal volume flow.
Formula:
A*B*x
(where x is an application-specific proportionality factor)
4. Select this formula as the source e.g. of the current output or of a modulated binary
output.
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