Filtering signal conditioner for sensor signal matching to a 4...20mA, 2-wire interface



The NV6a amplifies, filters and normalizes the output signals of SEIKA sensors. The symmetrical output signal enables unproblematic subsequent signal processing on the basis of 4...20mA current loop technology.
The NV6a does not require a separate supply voltage, as the internal operating voltage feeds off the current loop. The NV6a furthermore provides a highly stable 5V sensor supply voltage with short circuit current limitation.
Multiple internal switching variants allow for optimal adaptation of signal processing parameters, such as settling time, filter cut-off frequencies and amplification and zero point adjustment, to the measuring task.


The NV6a has its application anywhere a SEIKA sensor is, without much expenditure and under optimal compatibility, to be connected to measuring equipment operating on 4...20mA, 2-wire current loop basis and subsequent adjustment of amplification and zero position are necessary.
Typical applications are the coupling with memory programmable control systems and the signal transmission over long distances with little transmission line setup.

Technical Specifications

Terminal voltage 10V ... 30V (reverse polarity protected to -70Volt)
Minimum loop current excluding sensor 2.5mA ... 3.5mA
Maximum loop current 22mA ... 26mA
Operating temperature -40C ... +85C
Internally generated sensor supply voltage +5.00 Volt
Temperature drift of sensor supply voltage 20 ppm/Kelvin
Maximum allowable sensor current approx. 2mA
Signal loop current range 4...20mA
Zero current 12mA
Compensation range of sensor offset voltage US_offset 2.3V ... 2.7V (larger ranges, e.g. for B1 in Z direction on request)
Amplification range with respect to a loop current of 128mA US_offset100mV, US_offset300mV (on request)
Maximum load resistance at 24V supply voltage 500 Ohm
Signal-to-noise ratio 30Vs.s.
Signal-to-noise ratio with standard sensors > 65dB
Frequency range 0...10Hz, 0...200Hz, 0...1kHz, custom ranges on request
Electrical connections pin connector 2.54mm, length 5.7mm, 0.63mm gold-plated
soldering pads optional

Dimensions (in mm)


Attention! Sensor GND and NV6a GND (both at same potential) must be isolated from current loop! In a multiaxial arrangement (e.g. SW3), all sensor grounds must be isolated from each other. When ordering, look for "Sensor internally insulated, compatible with NV6a"!

This restriction is not applicable to signal conditioners with voltage output (NV4a, NV8a, NG..U, etc.)!

Since the supply voltages for the NV6a and the sensor feed off the current loop (they require at least 3mA), a terminal voltage of 8V to the NV6a must be guaranteed in order to ensure proper functionality even for the maximum loop current of approx. 24mA (highest voltage drop across load resistance).


SEIKA Mikrosystemtechnik GmbH - Ellharter Strasse 10 - 87435 Kempten - Germany - EMail: seika@seika.de