Vibro-meterGalvanicseparationunit

Power supply for 2-wires types of transducers and 

signal conditioners 

] μA to mV conversion for long distance signal 

transmission

] Certified for use with measuring chains in potentially 

explosive atmospheres

] Galvanic separation voltage: 4 kVRMS

] High rejection of frame voltage

] DIN-Rail mounting

The versatile GSI 124 galvanic separation unit replaces 

its predecessors: GSI 122, GSI 123 and GSI 130. The 

GSI 124 is for use with piezo-electric transducers with 

integrated electronics (eg. CE XXX), piezo-electric transducer signal conditioners (eg. IPC XXX) and proximity 

probe signal conditioners (eg. IQS 4XX series).

The unit is intended for use in 2-wire transmission systems at high frequencies. More generally, it may be used 

to supply any electronic system having a consumption of 

less than 20 mA.

The GSI 124 avoids the use of Zener barriers for Exi 

applications. It allows the transmission of AC signals 

over long distances. The unit rejects a large amount of 

the RMS voltage of ground noise and avoids AC noise 

pickup which can occur between the sensor case and 

the poles of the sensor.

BLOCK DIAGRAM

Environmental characteristics

General

Temperature

• Operating : 0°C to 70°C

• Storage : -20°C to +85°C

Vibration (according to IEC68.2.6) : 5Hz to 35 Hz, 90 minutes/axis

0.15 mm peak below resonance frequency, 1 g peak above

Humidity (according to IEC68.2.30)

• Operating : Up to 90%, non-condensing

• Storage : Up to 95%, non-condensing

Shock 

(according to IEC68.2.27)

: Half-sine, 6 g peak, 11 ms, 3 shocks/axis

Induced signal susceptibility 

(according to IEC61000-4-4/5)

: Performance criteria B

RF susceptibility 

(according to IEC61000-4-3)

: Performance criteria A

RF Emissions 

(according to IEC61000-4-3)

• Limits at 1 m : 30 MHz to 230 MHz < 60 dBμV/m (quasi-peak)

: 230 MHz to 1000 MHz < 67 dBμV/m (quasi-peak)

Electrostatic discharge

(according to IEC61000-4-2)

: Performance criteria B

Explosive atmospheres (ordering option A2)

• EC type examination certificate : LCIE 05 ATEX 6033 X

II (2) G (outside potentially explosive zone) [EEx ib] IIC

For specific parameters of the mode of protection concerned and special conditions for safe use, please refer to 

the “EC type examination certificate” that is available from Vibro-Meter SA on demand.

• cCSAus certificate : cCSAus certificate 1699234

Class I, Div 1, Groups A,B,C,D [Ex ia]

Electrical Characteristics

Power supply (user side)

Supply voltage

• With IPC XXX and CE XXX : 20 VDC to 30 VDC

• With IQS 4XX : 22.5 VDC to 30 VDC

Current consumption (with 24 VDC supply)

• Without load on transducer side : ≤ 20 mA

• With 12 mA on transducer side : ≤ 50 mA

• With 20 mA on transducer side : ≤ 70 mA

• With a short-circuit on transducer side : ≤ 70 mA

Output signal (monitor side)

Voltage output dynamic range (with 10 kΩ load) : ≥ 2 VDC

≤ U supply - 2.5 VDC

Output impedance : ≤ 1 Ω protected against short-circuits

Power supply voltage rejection ratio

• Standard (ordering option A1) : ≥ 55 dB at 10 Hz to 400 Hz

: ≥ 35 dB at 400 Hz to 100 kHz

• Explosive (ordering option A2) : ≥ 55 dB at 10 Hz to 400 Hz

: ≥ 35 dB at 400 Hz to 5 kHz

: ≥ 28 dB at 5 kHz to 100 kHz

Thermal output signal offset drift (0 ... 70°C) : ≤ 4 mV/°C (200 ppm/°C)

Thermal output signal sensibility drift (0 ... 70°C) : ≤ 100 ppm/°C

AC output signal residual noise

• Band width: 0 to 1 kHz : ≤ 2 μVRMS/√Hz

• Band width: >1 kHz : ≤ 4 μVRMS/√Hz

Input signal (transducer side)

Output supply voltage on 2-wires transmitting line : 21.5 VDC ± 2.5 VDC (without load)

Impedance : ≤ 90 Ω

Current dynamic range on 2-wires transmitting line : 0 mA to 20 mA

Short-circuit current limit on 2-wires transmitting line : ≤ 30 mA

Maximal load capacitance

• Standard : Cmax = 200 nF

• Explosive atmospheres : Cmax = 99 nF

Maximal load inductance

• Standard : Lmax = 30 mH

• Explosive atmospheres : Lmax = 25 mH

Transfer Characteristics (ordering option B)

Sensitivity

• IPC XXX and CE XXX : 1 V/mA ± 10 mV/mA

• IQS 4XX : 3.2 V/mA ± 32 mV/mA 

Output offset voltage (zero)

• IPC XXX (12 mADC on transmitting line) : 7 VDC ± 100 mVDC 

• CE XXX (5 mADC on transmitting line) : 7 VDC ± 100 mVDC 

• IQS 4XX (17.5 mADC on transmitting line) : 8 VDC ± 100 mVDC

Band width

IPC XXX and CE XXX (ordering option B1 and B2)

• Frequency band with a transfer inside ± 0.5 dB : DC to 20 kHz

• Typical frequency cut at -3 dB : 30 kHz

IQS 4XX (ordering option B3)

• Frequency band with a transfer inside ± 0.5 dB : DC to 10 kHz

• Typical frequency cut at -3 dB : 25 kHz

Linearity : < 0.2%

Galvanic separation voltage 4 kVRMS

Physical Characteristics

Dimensions : See mechanical drawing

Weight : 130 gr

Electronic housing material : Polyamide (PA 6.6) green

Electrical connections : With terminal screw - see m

o order please specify:

Type

Designation

Ordering number

: GSI 124 

: Galvanic separation unit

: 244-124-000-02X-A -B 

In this publication, a dot (.) is used as the decimal separator and thousands are separated by spaces. Example : 12 345.678 90. Although care has been 

taken to assure the accuracy of the data presented in this publication, we do not assume liability for errors or omissions. We reserve the right to alter any