LVDT Measurement (Module L*)68C3 Operations Manual North Atlantic Industries, Inc. 12/19/2014Rev: 2014-12-19-0947 www.naii.com Page 213 of 330Input Reference Frequency MeasurementEach individual channel input excitation frequency is measured and the value reported to a corresponding readregister. The input excitation frequency is reported to a resolution of 0.01 Hz. The output is in integer decimalformat.For example, if channel 1 input excitation is 400 Hz, the output measurement word from the correspondingregister would be 40,000.Input Signal Voltage (VL-L) MeasurementEach individual channel input signal voltage “VL-L” is measured and the value reported to a corresponding readregister. The input voltage is reported to a resolution of 10 mv rms. The output is in integer decimal format.For example, if channel 1 input signal voltage is 11.8 VRMS, the output measurement word from thecorresponding register would be 1180.Input Reference Voltage (VREF) MeasurementEach individual channel input signal voltage “VREF” is measured and the value reported to a corresponding readregister. The input voltage is reported to a resolution of 10 mv rms. The output is in integer decimal format.For example, if channel 1 input signal voltage is 11.8 VRMS, the output measurement word from thecorresponding register would be 1180.Signal Loss ThresholdEach individual channel input signal voltage “VL-L” is measured and the value reported to a corresponding readregister. The signal loss detection circuitry can be tailored to report a signal loss (at SIG Status register) at a userdefined threshold. This threshold can be set to a resolution of 10 mv rms. Program the threshold by writing thevalue of the voltage threshold in integer decimal format.For example, if channel 1 input signal loss voltage threshold is to be 7 VRMS, the programmed word to thecorresponding register would be 700 (2BCh).Reference Loss ThresholdEach individual channel input excitation voltage “VREF” is measured and the value reported to a correspondingread register. The excitation loss detection circuitry can be tailored to report a excitation loss (at REF Statusregister) at a user defined threshold. This threshold can be set to a resolution of 10 mv rms. Program thethreshold by writing the value of the voltage threshold in integer decimal format.For example, if channel 1 input excitation loss voltage threshold is to be 20 VRMS, the programmed word to thecorresponding register would be 2000 (7D0h).Signal StatusType: binary wordRange: N/ARead/Write: RInitialized Value: 0Check the corresponding bit for a channel’s Signal Status. A Signal input loss to that channel will trigger a bit failure (=1) on aper channel basis. Passing status (=0). Signal Loss is indicated after 2 seconds. Signal input monitoring is disabled during D3or D0 Test. Any Signal Status failure, transient or intermittent, will latch the Signal Status register. Reading any status bit willunlatch the entire register. Signal Status is part of background testing and the status register may be checked or polled at anygiven time. When Status Interrupt is enabled, Status Interrupt is reported through the Status Interrupt Vector in the GeneralUse Memory Map.REGISTER D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 FUNCTIONSIGNAL STATUS X X X X X X X X X X X X Ch4 Ch3 Ch2 Ch1 CHANNEL STATUS BIT
