PS-DC and PS-AC remote amplifier control units up to 22 or 18 amplifiers

Power, excitation and shunt calibration

The PS-DC and the PS-AC control Michigan Scientific spinning amplifiers. They power them with a bipolar ± 15 V supply, control the excitation of the strain gage bridges and command the amplifiers to apply their internal shunt calibration resistor to the appropriate arm of the bridge.

The PS-DC runs on 10 to 36 V DC, which suits automotive applications: it controls up to 22 spinning strain gage amplifiers, delivers up to 1 A and operates from −25 to 70 °C. The PS-AC runs on 100 to 120 V AC or 220 to 240 V AC at 50/60 Hz and is intended for the laboratory: it powers up to 18 strain gage amplifiers at 5 V bridge excitation on 350 Ω bridges, delivers up to 0.8 A and operates from 0 to 50 °C.

The amplifiers connect to the six-pin female PT02E-10-6S output connector, supplied with its mating connector on new units: ± 15 V, common, ground and calibration control. The PS-DC takes its supply on a three-pin male PT02E-8-3P connector. The power switch turns the unit on and lights the LED; on the PS-DC, the LED turns red on over-current, shunt calibration or bridge excitation off. The bridge excitation switch inverts the polarity of the ± 15 V pins, which turns the bridge excitation off without turning the amplifiers off. The shunt calibration switch puts + 15 V, high impedance or − 15 V on the calibration line, for positive or negative shunt calibration.

With bridge excitation off, what remains on the output is the noise the system picks up from undesired environmental conditions.