PXI LVDT/RVDT Simulator Module, 4-Banks

The 41-670-101 is ideal for the simulation of variable differential transformers (VDT), both linear (LVDT) and rotary (RVDT) types. It has four banks, each capable of simulating the output of a single 5 or 6-wire VDT or resolver, or dual 4-wire utilizing a shared excitation signal. This allows the module to simulate up to 4 channels of 5 or 6-wire or 8 channels of 4-wire.

Each VDT bank has an independent excitation input, and the ability to use an internally generated excitation signal. The module can also take a single input and distribute to all banks, reducing the load on the source and easing cabling. Due to the use of transformers, each input and output is galvanically isolated.

The LVDT, RVDT simulator modules are designed for a wide band of excitation frequencies, with 300Hz to 20kHz as standard, while also offering input voltages up to 38V and output voltages up to 32V. Each excitation input frequency and amplitude can also be independently read back.

The phase relationship between the input and output signals is automatically adjusted to lag one cycle, which means the phase delay can be negated. In applications where this is not acceptable, one of the outputs can be used to propagate the input signal resulting in an in-phase signal with the output, which can then be used for demodulation. 

With the addition of built-in relays, the 41-670 can also provide short or open circuits for each channel’s inputs and outputs, reducing the need for external switching for fault insertion requirements. The programmable phase delay can also be used for simulating imperfect sensors and cabling, artificially offsetting a single or multiple outputs. 

The output amplitude is programmed using several options; these include Vsum and Vdiff when operating in 5/6 wire, percentage displacement and independent voltage outputs. Vsum can be set as an absolute value or relative to the input amplitude. Phase relationship is controlled via a programmable propagation delay. Additionally, the module can be programmed with an actuator response, meaning rather than going from one position to the next directly, it can change at a constant rate defined by the user.