Alliance Sensors Group’s S2A DIN-rail-mounting LVDT signal conditioner is designed specifically for the power generation industry. It offers comprehensive diagnostics for sensor and wiring failure, real-time recalibration of the Full Scale and Zero outputs, enhanced ground loop noise rejection, and backward compatibility to legacy S1A signal conditioners. Utilizing front panel push buttons for easy calibration, the S2A is engineered to work with the widest range of LVDT, RVDT, and inductive half-bridge LVRT sensors by providing four excitation frequencies that will operate most AC-LVDTs over a 50 to 5,000 mVrms range of sensor output. S2A modules offer a choice of 8 analog outputs and half-duplex RS-485 digital communications to facilitate remote setup and for saving a module's setup parameters to hot swap them with another module.
Technical datasheets and additional information can be found below.
- - Cybersecurity Lock to Prevent Tampering
- - Smart Calibration by Front Panel Push Buttons -- No Pots, No Calculations
- - Color-Coded Detachable Terminal Plugs
- - Real-Time Recalibration
- - Comprehensive Diagnostics
- - Null Detection LEDs
| Operating Power: | +15 to +30 V DC (+24 V nominal), 100 mA max. at 24 V DC; +15 V DC and -15 V DC needed for ±10 V DC bipolar output |
| Excitation Voltage: | 3.0 Vrms (nominal) push-pull drive (factory default), 4.5 Vrms (nominal) push-pull drive (jumper J7 removed), 1.5 Vrms (nominal) single-ended drive for low impedance primary |
| Excitation Frequencies: | 1 kHz, 3 kHz, 5 kHz, 10 kHz (nominal) |
| Auto-Master Syncing: | Master output couples up to fifteen units; if original master fails, new master is automatically generated for fail-safe excitation control. |
| LVDT Output Range: | 50 mVrms to 5000 mVrms at LVDT’s full scale position |
| Analog DC Outputs: | 0 - 5 V, 1 - 5 V, 0.5 - 4.5 V, 0.5 - 9.5 V, 0 -10 V, -10 to +10 V, 0 -20 mA sourcing (3-wire), 4 -20 mA sourcing (3-wire) |
| Loop Resistance: | 850 Ohms maximum with 24 V DC supply |
| Output Non-Linearity: | ≤±0.025% of Full Span Output (FSO) |
| -3 dB Response: | 10% (minimum) of excitation frequency (normal setting); 10 Hz (default) user adjustable (low noise setting) |
| Noise and Ripple: | ≤1 mVrms (voltage output), or ≤2 μArms (current output) |
| Fault Detection: | Open or shorted LVDT winding, open, shorted, or grounded LVDT connection, LVDT cable disconnected, open or shorted analog output |
| Failure Indications: | Flashing LEDs; analog output driven out of range; 50 mA open-collector switch, user settable to NC (default) or NO |
| Null Detection: | Front panel LEDs; ±3V DC max. floating null output signal |
| Operating Temperature: | -20 to 75 C |
| Temperature Coefficient: | ±0.002% of FSO/C (combined span and zero shift) |
| Zero Set: | Front panel push button or RS-485 ASCII command |
| Full Scale Set: | Front panel push button or RS-485 ASCII command |
| Digital Interface: | RS-485 2-wire multi-drop network, 16 addresses |
| Cybersecurity Lock : | User enabled |
Download the S2A Signal Conditioner Datasheet- Download Comparison S2A to S1A Signal Conditioners
- Download The Differences Between the S2A and SC-200 Signal Conditioner
- Download S2A/SC-200 vs Competition - Signal Conditioner
- Download EU EC Declaration of Conformity S2A Signal Conditioner
- Download LVDT Signal Conditioner S2A Manual
The SC-200 is Alliance Sensors Group's general-purpose instrument grade DIN-rail-mounting LVDT signal conditioner, designed to serve the broadest possible range of AC-LVDT, RVDT, and inductive half-bridge sensor types through its four selectable excitation frequencies (2.5, 5, 7.5, and 10 kHz) and wide sensor output acceptance range (50 to 5,000 mVrms). This flexibility means a single SC-200 hardware platform can replace the specialized single-frequency conditioners that would otherwise be needed when a plant uses LVDTs from multiple manufacturers with different excitation requirements.
Push-Button Calibration Without Pots or Calculations
Legacy LVDT signal conditioners required adjustment of trim potentiometers for zero and span calibration — a procedure that could introduce calibration errors from pot resolution limitations and that required the technician to calculate the expected output at each calibration point. The SC-200 uses a push-button "teach" calibration procedure where the user positions the sensor core at the zero and full-scale positions, presses the corresponding calibration buttons, and the module's internal processor calculates and stores the appropriate gain and offset. This approach eliminates calculation errors and provides repeatable calibration results regardless of the technician's experience level.
Differential Input and Ground Loop Rejection
The SC-200's differential input rejects common-mode noise voltages that appear equally on both signal conductors — the dominant noise source in industrial environments where sensor cables run alongside power wiring and motor drive cables. Ground loops, which form when multiple pieces of equipment are grounded at different points in a plant's grounding system, inject noise into single-ended measurement systems but are rejected by a properly configured differential inputs. The SC-200's differential architecture provides significant noise immunity advantages over single-ended conditioners without requiring isolated power supplies or signal isolators.
Auto-Mastering and Multi-Module Systems
When multiple SC-200 modules are used in proximity — as they would be in a multi-axis measurement system or a bank of valve position sensors — when using the auto-master feature synchronizes all modules to a single excitation source. This eliminates inter-sensor magnetic coupling resulting in a beat frequency that could occur if adjacent sensors operated at slightly different frequencies, and allows the plant to use a single excitation frequency across all channels for simplified troubleshooting. The master module can drive up to fifteen slave modules, covering the typical size of multi-sensor panel installations.
