DAL-SIM-900 : LVDT Simulator

Voltage controlled testing of LVDT measurement electronics

Product Description

The DAL-SIM-900 simulates LVDT secondary signals for electrical verification of signal conditioners, displacement acquisition systems and automated test equipment. A 0 to 10 V DC command sets the simulated position through complementary VA and VB outputs with a shared CT terminal, enabling multipoint checks without moving a physical sensor.
The simulator operates from a nominal 24 V DC supply and uses an external 3 kHz, 4.25 Vrms sine-wave excitation. Its nominal normalized output ratio covers −0.9 to +0.9, with a nominal combined secondary amplitude of 4.0 Vrms.

1. Key features

• Standard 0–10 V command for manual or automated test sequences
• Three-terminal VA / CT / VB secondary interface
• Complementary outputs for negative, zero and positive simulated positions
• External excitation reference for connection to compatible LVDT electronics

2. Functional interface

The diagram shows external functions only. Signal names identify connection functions; final connector assignments are supplied with the product.

3. Nominal output characteristics

Increasing the command raises VA and lowers VB. At 5 V, both amplitudes are nominally 2.0 Vrms and the ratio is zero.

DC command	VA to CT	VB to CT	Normalized ratio
0 V	0.200 Vrms	3.800 Vrms	−0.900
5 V	2.000 Vrms	2.000 Vrms	0.000
10 V	3.800 Vrms	0.200 Vrms	+0.900

4. Applications

Zero and span verification • Automated multipoint verification of LVDT signal conditioners • Production testing.
Ratiometric acquisition evaluation • Troubleshooting of LVDT signal conditioner.

5. Technical specifications

Nominal conditions: 24 V DC supply; external 3 kHz, 4.25 Vrms sine wave measured at the excitation input with the simulator connected.

Parameter	Value or Description
Simulation channels	One LVDT channel with two complementary secondary outputs
Sensor signal configuration	Two excitation connections and three secondary connections (VA / CT / VB)
Supply voltage	24 V DC nominal
DC command input	0 to 10 V, referenced to signal GND
Excitation input	3 kHz, 4.25 Vrms sine wave nominal, excitation frequency can change
Control method	External analog command; a programmable DC source can automate test points
Secondary output interface	VA / CT / VB, shared secondary common
Normalized ratio range	−0.9 to +0.9 nominal
Secondary amplitude range	0.2 to 3.8 Vrms per channel, nominal
Secondary amplitude sum	VA + VB = 4.0 Vrms nominal
Ratio nonlinearity¹	Max 0.01% of the full ratio span

Result referenced to the straight line between endpoints and a full ratio span of 1.8. This is not a guaranteed accuracy limit; it excludes endpoint gain and offset error.

6. Command and ratio relationship

For command U in volts and RMS amplitudes VA and VB measured relative to CT, the nominal relationships at the specified excitation are:
R = (VA − VB) / (VA + VB) = 0.18U − 0.90
VA = 0.20 + 0.36U Vrms
VB = 3.80 − 0.36U Vrms

VA and VB are RMS amplitudes measured relative to CT. These amplitudes define the ratio; a true-RMS reading directly between VA and VB does not by itself establish the signed ratio. Output polarity and phase compatibility must be checked with the connected instrument.

7. Specification notes

The 4.0 Vrms amplitude sum is nominal at the stated excitation; it is not an exact constant or a regulated-output guarantee for other excitation conditions. Ratio nonlinearity describes departure from an endpoint straight line and must not be interpreted as total system accuracy.
Performance depends on excitation, connected load and command-source quality. Mechanical travel is not assigned: the equipment under test determines the displacement scale associated with the simulated ratio.

8. Signal connections

Signal	Connection function
24 V DC power input	Connect the designated supply positive and return terminals.
EXC_P / EXC_N	Connect a compatible external excitation source, including the equipment under test where suitable.
ADJ_DC_IN / signal GND	Connect the 0–10 V command source and its return.
VA	Secondary A output; amplitude measured relative to CT.
CT	Shared secondary common; separate from the DC command return.
VB	Secondary B output; amplitude measured relative to CT.

Signal names identify functions, not connector pin numbers. Use the confirmed product connection drawing when wiring the unit.

9. Connections and operation

1. Connect the nominal 24 V DC supply to the designated power input.
2. Connect a compatible excitation source to EXC_P / EXC_N and verify the loaded amplitude.
3. Connect the command source to ADJ_DC_IN and signal GND.
4. Connect VA / CT / VB to the secondary input of the equipment under test.
5. Verify the 0 V, 5 V and 10 V command points, then run the required test sequence.
CT is the secondary common, not the DC command return. Use signal GND for the command source. The simulator verifies electrical measurement channels; it does not reproduce a physical sensor’s mechanical behavior.

10. Compatibility and selection

Specify the conditioner model, excitation voltage and frequency, secondary wiring, input load and required test speed when ordering. The VA / CT / VB interface addresses a shared-common secondary configuration; compatibility with other wiring arrangements requires confirmation. A standard DC PLC input requires an LVDT conditioner between it and the simulator.
The specified function is LVDT secondary-amplitude simulation. Resolver modes, programmable phase shift and open-circuit or short-circuit fault insertion are outside the specified feature set. Output loading, supply tolerance, temperature range, settling time, phase error and isolation ratings require confirmation for the intended application.

We also accept customized requirement for LVDT simulator.