Remote Silo Weighing
The Problem:
A customer needed to monitor the weight of a number of remote silos using the analogue inputs of a PLC. The distances involved ruled out the use of voltage-output conditioners as the resistance of the wiring would introduce measurement errors.
The Solution:
The solution was to use multiple SGA instruments configured for 4-20mA current loop output thereby overcoming the voltage drops associated with long cable runs.
Each silo was fitted with a 350 Ohm load cell in each of its four legs. These were wired in parallel to an SGA to average their outputs and provide a measurement of the weight of the silo. The SGA’s offset switches enabled the weight of the silo to be tared off leaving the true weight of the contents.
Products used in this application:
Strain Gauge Signal Conditioning for Load Cells
SGA A&D
