The V460 is a VME-based versatile source/measurement unit. It includes a programmable constant-current source, a precision programmable gain 16-bit analog-to-digital converter, and a 4-wire, 16-channel analog multiplexer. An internal microprocessor supervises channel scanning according to user loaded parameters, reporting sensor voltage drops or, for selected sensor types, engineering-unit data.
The V460 is ideal for precision temperature measurement, using mixed resistive and diode sensor types. The programmable current sources and low duty-cycle scanning assure low sensor self-heating. Programmable digital filtering allows selectable rejection of AC line hum and other noise sources.
The V460 can measure resistances from 5.12 Megohms full scale (with 78 ohm resolution) to 80 ohms full scale (with 1.22 milliohm resolution); voltages from 5.12 volts full scale to 80 mV full scale may be measured, with resolution to 1.22 microvolts. Extensive internal self-tests help assure accurate measurements.
FUNCTION | 16 channel VME current source and analog measurement module |
DEVICE TYPE | 16-bit VME register-based slave: A16:D16:D08(EO) Implements 64 16-bit registers at switch selectable addresses in the VME 16 bit addressing spaces |
CHANNELS | 16 channels, 4-wire sensor connections |
INPUTS | Less than 1000 MΩ DC leakage current less than 200 pA Inputs are not isolated from circuit common |
ADC | 16 bits, programmable 0/+5.12 volts or ±5.12 volts full scale; programmable preamplifier gains of 1, 4, 16, and 64 magnify
full-scale span to 80 mV (LSB resolution 1.22 µV) Accuracy ±0.01% ±25 PPM/K The ADC is monotonic to 16 bits |
RESISTANCE | Resistance measurements are accurate to ±0.01% ±30 PPM/K for ISRC >1 µA , with preamplifier gains of 1, 4 and 16 |
SCAN RATE | Typically 20 ms per channel; full scan of 16 channels requires less than 400 ms Certain programmable options may increase scan times |
CURRENT SOURCE | Per-channel programmable to 0, 1 µA, 10 µA, 100 µA and 1 mA Accuracy ±0.01% ±25 PPM/K, except 1 µA current is ±0.04% ±50 PPM/K |
LINEARIZATION | Includes engineering units conversion for Lakeshore cryo-diode sensors and ISO 385 curve platinum RTDs (100Ω or 1000Ω) |
FILTERING | Per-channel programmable digital lowpass filtering provides selectable time constants up to 128 samples Sample timing and filtering are optimized for 50/60 Hz hum rejection |
OPERATING TEMPERATURE | -20 to +70°C; extended MIL/COTS ranges available |
CALIBRATION INTERVAL | One year |
POWER | Standard VME supplies: +5 volts, 1.5 A nominal +12 volts, 50 mA nominal (plus load current) -12 volts, 50 mA nominal (plus load current) |
CONNECTORS | Two front panel female D37 connectors |
INDICATORS | Three LEDs, VME access, sensor SCAN performed and PASS/FAIL self-test |
PACKAGING | 6U single-wide VME module |
CONFORMANCE | ANSI/VITA 1-1994 (R2002) VMEbus spec |
V460-1: 16-channel VME current source and analog measurement module