TB20 Function module – Strain gauge weighing module

Part of the Helmholz decentralized fieldbus I/O system – TB20

The TB20 Function Mode – Strain gauge weight module. The weighing module serves the purpose of measuring and processing signals from weight, torque, or force sensors. The weighing module enables the direct connection of a load cell in the strain gauge full bridge circuit (voltage-fed bridge circuit).

The feed voltage of the bridge is generated from the back wall bus of the TB20 and amounts to 5 V with a maximum 70 mA load. The voltage output is protected with an internal, reversible fuse against overload and short circuit. Weighing cells with a maximum of 72?? can be connected. The external bridge feed of the load cell is possible.

The bridge voltage can be measured on the load cell with 6-wire connection. The measured value is incorporated into the calculation of the measurement value. Controlled by the application, wire break detection can also take place by feeding test current into the measurement channel.

The input channels have a resolution of 24 bits. Measurement values are issued configurable in mV/V or in kg.

With adjustable sample rates, interference voltages and mechanical fluctuations in the measurement can be suppressed. Disruptions from a series of measurement values can be smoothed out using a moving mathematical average. A zero point comparison of the load cell can be carried out with the offset, or measurement with a definite value can be commenced with. Linearity deviations of the measuring instruments can be linearized with up to 5 sampling points.

The measurement inputs have overvoltage protection relating to the 24 V potential and possess electrical isolation with 500 V dielectric strength.