MODEL 635-004 STRAIN GAGE AMPLIFIER ASSEMBLY

Features

• Versatile switch selectable modes
• Auto bridge balance with battery backup
• Separate DC channel
• Isolated excitation source
  

Description

The Model 635-004 strain gage amplifier exhibits the performance characteristics and controls derived from 20 years of customer-oriented experience. It features very low output noise, broad-band response, auto and manual bridge balance and many other conveniences, all combined in one moderately priced module. The -004 version mounts ten channels in a standard 19" wide rack by moving the power supply under the modules.

Specifications

Bridge configuration: Quarter, quarter dynamic, half, and full bridges, switch selectable; can also be used as general purpose differential amplifier

Bridge completion: Switch selects either 120 ohm or 350 ohm internal precision completion resistors

Bridge excitation: Front panel adjustable, isolated 1.25 VDC to 15.0 VDC; front panel on/off switch; monitor connector provided for voltmeter

Bridge balance: Front panel switch, rack pushbutton, or remote control activates automatic bridge balance cycle; LED indicates unbalanceable condition; Balance switch selects internal autobalance or manual balance trimpot

Operating modes: Switch selects AC coupled, DC coupled, Zero, DC cal or External cal signal

Gain:	Main channel	Front panel switch selectable gains of 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000, 5000 with gain vernier
	DC channel	Board-mounted jumper selectable gain of 1, 100, 200, 500

Frequency response:	Main channel	DC to 250kHz, with switch selectable 3-pole active filter at 1Hz, 10Hz, 100Hz, 1kHz, and 10kHz -3dB frequencies AC coupled low frequency rolloff at 10Hz
	DC channel	DC to 10 Hz

Calibration:	Shunt cal	Activated by front panel MODE switch or remote command; front panel R CAL switch selects one of four internal calibration resistors; toggle selects + or - bridge resistor to be shunted
	External cal	Activated by front panel MODE switch or remote command; signal applied to rear panel BNC is connected to amplifier input

Signal outputs:	Main:	±10V max, 100mA peak load
	Tape:	±10V max, 5mA peak load
	DC channel:	±10V max, 10mA peak load

Test points: Front panel two-pin Twin BNC connectors (Amphenol 31-2225) monitor bridge signal, bridge excitation, and amplifier output

Output limit: Front panel LED lights if output signal exceeds 1V RMS

Output noise: 2.5 microvolts RMS RTI max, DC to 10kHz at G=1000

Power: Model 858 rack-mounted power supply module provides unregulated ±24V, plus unregulated isolated supply for bridge excitation

Mechanical: 19"W x 10.5"H x 14"D, 10 module rack adapter, Model 4023-102

Carrying case: 2 module (8.75" high) desktop case, Model 4025-102

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