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Friday, January 28, 2022 · 0 min read

New SIRIUS UNI Universal Strain Gauge, IEPE, Voltage, RTD, Resistance, and Current Amplifier

Can SIRIUS STG amplifier become even more universal? Yes, it can!

The newly released SIRIUS UNI amplifier adds IEPE signal input to the already known STG amplifier. The module is based on the SIRIUS DualCoreADC® technology enabling a high dynamic range (> 160 dB). The amplifier also offers a high voltage range. Improved excitation current accuracy enables constant current supply for quarter bridge applications (2- or 4-wire).

SIRIUSi-8xUNI data acquisition system with universal signal inputs

With the introduction of native IEPE mode, the module supports DC or AC mode input coupling with 0.16 Hz high-pass filter for low ranges (0.3 Hz for 100 V range).

SIRIUS UNI supports both Class 1 and Class 2 TEDS.

The input connector is D-SUB9, the optional connector is a female 10-pin LEMO 2B series (on request 8-pin LEMO-2B, 16-pin LEMO-2B).

Main features

  • Universal input: Voltage, Full/Half/Quarter bridge strain (120 Ω and 350 Ω), constant voltage/current supply, IEPE, Potentiometer, RTD, Resistance, Current (ext. Shunt).

  • High voltage range (up to ±100 V).

  • Better excitation current accuracy.

  • Quarter bridge constant voltage/current supply.

  • High dynamic range.

  • Dual TEDS support (Class 1 & Class 2).

SIRIUS UNI is available in an isolated and differential version. It comes as a single or a rack slice and with UNI+, counter option. For details check the order codes below.

Universal amplifier for dynamic and static strain measurements 

The SIRIUS UNI amplifier supports a bunch of different connection methods for strain gages, selectable in software:

  • Full bridge 6 wire / 4 wire

  • Half bridge 5 wire / 3 wire

  • Quarter bridge 3 wire / 4 wire

Usually the most common is the “constant voltage supply”, furthermore when using the sense lines, cable influences can be cancelled by pressing the “Compensate” button in channel setup.

The “constant current supply” for more demanding applications gives a better sensitivity output even when the cable resistance will change a lot during the measurement due to temperature. So far, the minimum connection method was 3-wire.

SIRIUS UNI amplifier 3-wire connection method

In high temperature strain measurements – on gas turbines, combustion engines, aerospace applications… - the change of lead wire resistance might not be symmetrical. This would indicate strain which physically does not exist. For dynamic strain measurements the static strain value can be removed by selecting AC coupling.

The SIRIUS UNI amplifier comes with a new Quarter Bridge CC (Constant Current) mode, which allows the use of only 2 wires. This AC-coupled resistor measurement is especially needed for rotating machines, where the number of slip ring contacts is limited.

SIRIUS UNI amplifier 2-wire connection (Quarter CC mode) for dynamic strain

SIRIUS UNI amplifier connector pinouts

DSUB9 connector

SIRIUS UNI amplifier DB9 connector pinout
1Exc+Excitation +
2In+Input +
3Sns-Sense -
5R+¼ Bridge/Shunt
6SNS+Sense +
7In-Input -
8Exc-Excitation -
SIRIUSi 8xUNI front panel
SIRIUSi 8xUNI back panel

LEMO 10-pin connector

SIRIUS UNI amplifier 10-pin LEMO connector pinout
1Exc+Excitation +
2Exc-Excitation -
3In+Input +
4In-Input -
5Sns+Sense +
6Sns-Sense -
7DI-CNTDigital I/O, Counter
9R+/SHUNTResistance / SHUNT

SIRIUS UNI technical specifications

For full specification about SIRIUS UNI amplifier, please check the SIRIUS technical specifications page.