Davey Speedman Dual Pump Variable Speed Pump Control System - Manual (Page 50)

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CALIBRATION OF ANALOGUE SENSORS
The Speedman can accept most analogue signals from sensors and requires that a calibration routine be run
to set both SCALING and ZERO OFFSET of these sensors.
Go to the CONFIGURE Menu and press the Enter Key.
ZERO ERROR
The Zero Error routine should be done BEFORE using the “Adjust Pressure” screen.
The zero error offset is trimmed out on the “Transducer Zero” screen. Make sure there is no pressure in the
system or in the tube leading to the transducer.
Zeroing the transducer can be done two ways. Either via automatic method or manual method.
Automatic Method
On the “Transducer Zero” screen press ENTER to edit the data. Then press and hold both up and down
for 2 seconds then release. On the screen should read “Finding Zero – Please Wait”, this will take about
5-20 seconds depending on the value you have set for averaging. After it finishes it should show the value
0, if it shows 1 or VALUE TOO LOW, then a minor amount of fine tuning will be required. The fine tuning is
accomplished using the Manual Method Below, In short press the down button to decrease the value, and if
the screen shows “VALUE TOO LOW” press the UP button until zero appears.
Manual Method
On the “Transducer Zero” screen press ENTER to edit the data
and then DOWN to make the reading go to “0”. Wait for 5 seconds
for the reading to stabilise. Take care when running this procedure
to reduce to the “zero” value slowly as the possibility of running past
is high.
The pressure readings are averaged so the readings can lag
behind the key presses. Always allow the system to stabilise prior
to completing this procedure.
If the value input is lower than Zero a message stating, “VALUE TOO LOW” will appear on the screen. Press
the UP key until a “zero” value appears.
Once completed, press ENTER again and back out of the menu to initiate a store of the “zero” value.
PRESSURE ADJUSTMENT
For this routine it is necessary to have a reference
pressure that can be used to compare the system
pressure to the pressure that the Speedman senses.
To calibrate the scaling for the analogue sensor apply
a pressure to the system and allow it to stabilise.
This can be done by manually starting one pump and
then closing the main isolation vale and shutting down
the pump. This should hold system pressure and
remove any fluctuations that are prevalent when
pumps are running.
The system pressure should be set at least two times higher than the standard operating pressure, as the
calibration routine works best with an end of scale reading.