DI-5B38 Strain Gage Input Modules

Narrow (4Hz) & Wide (10kHz) Bandwidth

Product Features

• Interfaces to 100Ω Through 10kΩ Full-, Half-, or Quarter-Bridge Strain Gages
• High Level Voltage Outputs
• 1500Vrms Transformer Isolation
• ANSI/IEEE C37.90.1-1989 Transient Protection
• Input Protected to 240VAC Continuous
• Fully Isolated Excitation Supply
• 160dB (Narrow BW) or 100dB (Wide BW) CMR
• 4 Hz (Narrow) or 10k Hz (Wide) Signal Bandwidth
• ±0.08% Accuracy
• ±0.02% Linearity
• ±1µV/°C Drift
• CSA Certified

Products in the Series

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Each DI-5B38 strain gage input module provides a single channel of strain gage input which is filtered, isolated, amplified, and converted to a high level analog voltage output. This voltage output is logic-switch controlled, allowing these modules to share a common analog bus without the requirement of external multiplexers.

The DI-5B38 module is designed with a completely isolated computer side circuit which can be floated to ±50V from power common (pin 16). This complete isolation means that no connection is required between I/O common and power common for proper operation of the output switch.

The DI-5B38 can interface to full- or half-bridge transducers with a nominal resistance of 100Ω to 10kΩ. A matched pair of bridge-completion resistors (to ±1mV at +10V excitation) allows use of low cost half- or quarter-bridge transducers. On wide bandwidth modules, the 10kHz bandwidth allows measurement of high speed processes such as vibration analysis.

Strain gage excitation is provided from the module by a very stable 10V or 3.333V source. The excitation supply is fully isolated, allowing the amplifier inputs to operate over the full range of the excitation voltage. Full scale sensitivities of 2mV/V, 3mV/V, or 10mV/V are offered. With 10V excitation, this results in a ±20mV, ±30mV, or ±100mV full scale input range.

On wide bandwidth modules, the input signal is processed through a pre-amplifier on the field side of the isolation barrier. This pre-amplifier has a gain-bandwidth product of 5MHz and is bandwidth limited to 10kHz. On all modules, after the initial field-side filtering, the input signal is chopped by a proprietary chopper circuit. Isolation is provided by transformer coupling, again using a proprietary technique to suppress transmission of common mode spikes or surges. The module is powered from +5VDC, ±5%.

A special input circuit on the DI-5B38 provides protection of the signal inputs and the isolated excitation supply up to 240VAC.