The LCD20 is designed to connect to a ‘Top Hat’ DIN rail.
Access to various connectors and buttons is gained by opening the front panel door. This is hinged at the opposite side to the LEDs.
The LCD20 offers a direct connection to a range of low level (foil) strain gauge sensors.
Gain sensitivity is optimised for two ranges, 0.5 to 3.7mV/V and 3.7 to 7.8mV/V selected by the Sensitivity parameter in the menu.
A stable 5VDC excitation supply at 150mA is provided which is sufficient to power up to four 350 ohm load cells connected in parallel.
Ratiometric strain gauge measurements are taken which cancel out errors caused by changes or drift in Excitation voltage. The LCD20 facilitates 6 wire measurement which allows for voltage drops caused by long cable lengths between the LCD20 and the load cells, where barriers are used or if the load cells are powered from another source. Where possible, use 6-wire connections to the load cells.
For load cell connections we recommend the use of 3 pairs of twin twisted pair cable such as Alpha Wire 5123C SL005 available from Farnell 130-2249.
The pairs should be arranged as follows:
Excitation pins 1 & 6
Sense pins 2 & 5
Signal pins 3 & 4