AC-LVDT Signal Conditioner

 Alliance Sensors Group introduces the S1A AC-LVDT Signal Conditioner that offers smart and fast LVDT setup with built-in null indication and simple front panel pushbuttons to set zero and full scale.  Engineered to work with the widest range of AC-LVDTs, RVDTs and inductive half-bridge sensors including 3-wire GE LVRTs and gas turbine LVDTs, the S1A DIN rail module supports LVDT operation and indicates most common failures.  The S1A offers a choice of 4 excitation frequencies, 8 analog DC outputs (6 DC voltage and 2 current loop outputs) and RS-485 digital communications.  Ideal applications for the S1A module include turbine control systems, steam valve position feedback, and other types of redundant control systems that use LVDT position sensors. In the past, AC-operated LVDT linear and rotary position sensors were difficult to calibrate as traditional signal conditioners require operators to use trimmer pots.    

With the S1A AC-LVDT Signal Conditioner, the internal microprocessor eliminates the need to calculate jumper connections for gain, range, etc. The operator simply finds null, then moves the LVDT core to one end of the range and presses the zero button. Once set, the LVDT core is moved to the other end of a specified range and the full scale button is pressed.  The S1A is fully calibrated with the position sensor. “The S1A works with about 98% of AC-operated LVDTs on the market, including GE gas turbine LVDTs,” notes John Matlack, VP of Sales and Marketing, Alliance Sensors Group. “With its built-in null indicator and smart setup with two front panel push buttons, the S1A AC-LVDT Signal Conditioner can calibrate LVDTs 4 to 20x faster than traditional signal conditioners.” In the event of a failure, a new S1A DIN rail module can be “hot swapped” into an existing installation, with initial calibration data saved then reloaded via RS-485 port.  Standard signal conditioners would require a full calibration. 

Through the digital communications link, the S1A also can be setup remotely using a computer, which simplifies operations if the unit is already installed on a DIN rail in a cabinet. For installations where there are multiple position sensors, the S1As can be master/slaved to prevent cross talk between sensor signals. Should a master fail, standard signal conditioners will revert back to their own oscillators, opening them to the cross talk the master/slave configuration was designed to prevent. If the S1A master fails, the first slave becomes the new master for the other slaves.