GSI127 244-127-000-017-A1-B05 is a voltage-mode galvanic separation unit with signal inverting capability. As a special configuration within the GSI127 product family, the B05 model not only inherits the series' outstanding electrical isolation, noise immunity, and explosion-proof safety features but also integrates a precise inverting transmission function with a gain of -1 V/V. It is specifically designed for industrial monitoring applications that require electrical isolation of voltage signals while simultaneously achieving polarity reversal or phase compensation.
In many complex monitoring systems, the output signal polarity of a sensor or front-end signal conditioner may not match the expected input polarity of the monitoring system. Direct connection can lead to confused measurement logic and even false alarms. Traditional solutions involve adding extra inverting circuits or complex software compensation, which introduces additional error points and increases system complexity. The GSI127 B05 unit integrates safety isolation and precise inversion into one, providing a simple, reliable, and high-precision single-device solution. It is particularly suitable for connecting specific voltage-output sensors and conditioners whose output signal polarity is negative or requires inversion, ensuring the signal's amplitude and phase meet design requirements before being sent to the monitoring system. Choosing B05 means selecting an intelligent interface that solves polarity matching challenges while providing the highest level of electrical safety and signal integrity.
2. Model Decoding and Exclusive Configuration Details
The model number 244-127-000-017-A1-B05 precisely reveals its unique signal processing capabilities:
GSI127: Base product platform, representing the Galvanic Separation Unit.
A1: Environmental & Safety Identifier. Indicates the unit is an Explosion-Proof Certified Version suitable for Zone 2/Div. 2 hazardous areas. The iconic blue sensor-side terminal block is clearly visible on the grey housing, complying with explosion-proof installation standards.
B05: Core Function & Performance Code. This is the exclusive identifier for Inverting Voltage Transmission Mode, defining its key characteristics:
Operating Mode: Voltage Input, Voltage Output (V/V) Mode. Like B04, its sensor side is a high-impedance voltage input interface that does not supply power externally.
Transfer Function: -1 V/V ±1% Inverting Amplified Isolated Transmission. This is the soul of B05. This function means: the output signal has equal amplitude to the input signal but opposite polarity (phase). That is, V_out = -1 * V_in + V_offset, where V_offset is the output offset voltage (zero point). This achieves precise 180° phase inversion.
Input/Output Range: The sensor-side input voltage range is 0 to 20 VDC, corresponding to a monitor-side output in the 20 to 0 VDC inverted range (specifics depend on zero point and gain).
Zero-Point Reference: The output offset voltage is preset to 10.00 VDC ±200 mV. This zero point corresponds to a 10 V DC static voltage on the sensor-side input line. This means when the input is 10V, the output is precisely inverted and biased to 10V, providing a symmetrical reference center point for bidirectional signal swing.
3. Typical Application Scenarios & System Integration Scheme
GSI127 Model 244-127-000-017-A1-B05 solves special signal polarity matching problems in voltage monitoring chains. Its main application scenarios are as follows:
Application Scenario 1: Sensor Systems with Negative Voltage Output (e.g., Certain Proximity Probe Systems)
Background: Some eddy current proximity probe systems (e.g., certain IQSxxx conditioner configurations) output a negative DC voltage inversely proportional to the gap (e.g., gap decreasing, output voltage changes from -2V towards -18V). Many monitoring systems (e.g., PLC/DCS analog input cards) only accept positive voltage inputs (e.g., 0-10V or ±10V).
Traditional Dilemma: Direct connection would cause the signal to exceed the card's negative input range (if available) or cause logical reversal (if the card only accepts positive voltages).
B05 Solution:
Connect the IQSxxx's negative voltage output (e.g., -10V representing nominal gap) to the GSI127 B05.
The B05 performs the operation V_out = -1 * (-10V) + 10V = 20V (simplified understanding; actual is linear inversion with offset). Through precise -1 V/V inversion and 10V zero-point bias, it outputs a positive voltage signal proportional to the original physical quantity (gap) (e.g., 20V for minimum gap, 0V for maximum gap, 10V for nominal gap).
The monitoring system receives this positive voltage signal for correct calibration and display. B05 simultaneously provides 4 kV safety isolation.
Application Scenario 2: Specific Monitoring Logic Requiring Phase Inversion
Background: In some customized or legacy systems, the output signal phase of a sensor or conditioner may be opposite to the "positive direction" defined by the monitoring logic. For example, a sensor defined as "positive displacement represents moving away" might output a decreasing voltage as it moves away, conflicting with the monitoring system's internal logic that "higher voltage represents larger displacement."
Solution: Use the B05 unit to invert the signal, "flipping" the sensor's output characteristic to match the monitoring system's internal logic definition, without modifying complex underlying software or sensor orientation.
Application Scenario 3: Forming Differential or Push-Pull Input Structures with Other Devices
In precision measurements requiring high common-mode rejection ratios, differential signals are sometimes used. The B05 can provide a precise inverted version for one signal path, forming a differential pair with the other original signal for input to a subsequent instrumentation amplifier.
Key Differences Between B05 and B04 (In-Phase Voltage Isolator) and Selection Criteria:
Functional Essence: B04 is a "follower," reproducing the input; B05 is an "inverter," outputting the opposite polarity of the input.
Transfer Curve: On a plot of input voltage (X-axis) vs. output voltage (Y-axis), B04 is a line with a slope of +1 (passing through the 10V zero point); B05 is a line with a slope of -1 (also passing through the 10V zero point).
Selection Principle:
If the sensor outputs a positive voltage and the monitoring system expects a positive voltage -> choose B04.
If the sensor outputs a negative voltage and needs conversion to a positive voltage -> choose B05.
If the sensor outputs a positive voltage, but the system logic requires an inverted signal -> choose B05.
Absolutely forbidden to use B05 for current loop (B01/B02/B03) or in-phase voltage (B04) scenarios requiring faithful signal reproduction, as this will cause completely erroneous signal logic.
4. Installation, Wiring & System Commissioning Guide
Installation: Standard DIN rail mounting in a safe-area control cabinet.
Power Wiring: Connect the 18-30 VDC operating power for the GSI127 (to the bottom monitor-side terminals).
Sensor-Side Critical Wiring:
Confirm Signal Polarity: Always use a multimeter to confirm the polarity (positive/negative) and static voltage value of the upstream device's output signal.
Connect the upstream device's voltage output to the GSI127 B05 top (blue) input. Pay attention to terminal definitions to ensure signal and return lines are correctly matched.
Shield Handling: Ground the cable shield at a single point at the signal source end. Leave the shield floating and insulated at the B05 end.
Monitor-Side Wiring: Connect the B05 bottom output to the monitoring system. Special Attention: Because the B05 output characteristic is inverted, corresponding range calibration must be performed in the monitoring system software to ensure the correct positive/negative relationship between the physical quantity (e.g., gap, displacement) and the reading.
System Commissioning & Calibration:
Zero-Point Verification: When the upstream device outputs its defined "zero" or "nominal" voltage (e.g., -10V for an IQSxxx), measure the B05 output. The theoretical value should be 10 VDC ±0.2V. This is key to verifying the correct system baseline.
Full-Scale Verification: Cause the upstream device to output its maximum and minimum signal values, measure the B05 output respectively, and verify that they fall within the valid input range of the monitoring card (e.g., 0-20 VDC) and that the direction of change is as expected.
System Calibration: In the monitoring software, set the correct engineering unit conversion factors based on the B05's input-output inversion relationship (V_out = -1 * V_in + 10V) and the sensor's own input-output relationship.
