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LCM Systems Ltd
Unit 15, Newport Business Park, Barry Way
Newport, Isle of Wight, PO30 5GY, United Kingdom
Tel: +44 (0) 1983 249264 Fax: +44 (0) 1983 249266
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Example
You have a load cell rated at 50te and the calibration certificate shows
the equivalent output for the cal figure to be 40.5te.
5 40.5
50
5 0.81
.
(5) Based on the example provided above, Adjust the COARSE GAIN and the FINE GAIN
potentiometers until your DVM shows 4.05V.
(6) The amplifier will now be scaled to give you a 0-5V output from zero to the full rated load of your
load cell.
(7) Switch off the CAL (toward centre of the board) and recheck the zero. Repeat the above steps
until you are satisfied with the scaling accuracy.
The CAL injects a dummy signal to the LCTA, which simulates a load being applied to the load cell. This
can be used at any point in the future to ensure correct operation of the system.
Adjusting the Trip point values
The trip outputs consist of two independently adjustable changeover relays with volts-free contacts. Each
relay remains de-energised, with its COM terminal connected to its NC pin, until the signal level exceeds
the respective trip level. At this point, the relay energises and the COM terminal is instead connected to
the NO pin.
(1) Connect your DVM, positive lead to TRIP 1 TEST POINT, and the negative lead to the 0vdc field
terminal (terminal 16).
(2) Calculate the required trip 1 test point reference voltage required for trip 1, by using the equation
below:-
1 5 1
Example
You have a load cell rated at 50te and you want Trip 1 to activate at a trip
load value of 45te
1 5 45
50
1 5 0.90
.
(3) Based on the example provided above, adjust the TRIP 1 SET potentiometer until your DVM
reads 4.50V
(4) You have now set TRIP 1 correctly. Repeat the same procedure for Trip 2, with you DVM positive
lead connected to TRIP 2 TEST POINT, adjusting TRIP 2 SET.
