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Details, datasheet, quote on part number:1550A
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Datasheet text preview:
1550A
Vishay Micro-Measurements
Strain Indicator Calibrator
FEATURES
· True Wheatstone bridge circuitry · Simulates quarter, half & full bridge -- both 120/350 · Three decades of push buttons · Strain range direct reading: ±99 900µe. . . increments of 100µe · Transducer range: ±49.95 mV/V. . . increments of 0.05 mV/V · Reversing switch for plus and minus calibration · High precision Vishay resistors used throughout to ensure excellent stability · Accuracy 0.025 percent -- traceable to the U.S. National Institute of Standards and Technology
A laboratory standard for verifying the calibration of strain and transducer indicators.
DESCRIPTION
Sound engineering and laboratory practices require that the instrumentation used to make critical strain measurements b e periodically calibrated to verify that it is within the m a n u f a c t u r e r 's original specifications. Additionally, each type of strain indicator exhibits some degree of nonlinearity, especially for large strains during quarter-bridge operation. Since this is the most common stress analysis application of s t r a i n gages, it is important that the strain indicator be calibrated in this mode. Instrumentation span should also be checked at a number of points before each important test to avoid inaccurate data. The Model 1550A calibrator is a Wheatstone bridge and generates a true change of resistance in one or two arms of the bridge. It simulates the actual behavior of a strain gage in both positive and negative strain. T h e `star network' used in certain other commercial calibrators provides a substantially lower cost instrument design, because component specifications are less critical, and fewer components are required. However, the `star network' cannot simulate quarter-bridge strain gage behavior, and cannot simulate positive strain. Another serious problem with this circuit is that the bridge i n p u t and output resistances change in an abnormal manner, leading to inaccuracies in calibration under some conditions. A calibrator based on the Wheatstone bridge principle requires stable components. A total of 66 ultra-stable Vishay p r e c i s i o n resistors are used in the Model 1550A calibrator to provide the stability, repeatability, accuracy and incremental steps required in a laboratory standards instrument.
WHEATSTONE BRIDGE / STAR NETWORK
Document Number: 11313 Revision 03-Feb-03
micro-measurements@vishay.com
www.vishaymg.com 1
1550A
Vishay Micro-Measurements
Strain Indicator Calibrator
A certificate of calibration is provided with each Model 1550A calibrator
SPECIFICATIONS
Accuracy: 0.025% of setting ±1µ (0.0005 mV/V), maximum. Traceable to United States National Institute of Standards and Technology. Repeatability: ±1µ (0.0005 mV/V), maximum Stability: (0.001% of setting ±1µ)/°C, maximum Thermal EMF: 0.5 µV/V of excitation, maximum Bridge Resistances: 120 and 350. Input Resistance: ±0.05%, maximum, from nominal at all output settings. Output Resistance: ±0.05%, maximum, from nominal at "000"µ, 0.25% at ±99 900µ. Circuit: True ±R in two adjacent arms (opposite signs), plus two fixed arms for bridge completion. Simulation: Quarter bridge, one active arm. Half bridge, one or two active arms. Full bridge, two active arms. Range: Two active arms: 0 to ±99 900µ in steps of 100µ @GF = 2.00. 0 to ±49.95 mV/V in steps of 0.05 mV/V. One active arm: 0 to ±49 950µ in steps of 50µ @ GF = 2.00. Excitation: To meet accuracy and repeatability specifications: 120: Up to 10 Vdc. 350: Up to 15 Vdc. Maximum Permissible: 120: 25V ac or dc. 350: 30V ac or dc. Output @ 000: 50µ (0.025 mV/V), maximum in full-bridge mode. Environment: Temperature: +50° to +100°F (+10° to +38°C). Humidity: Up to 70% RH, non-condensing. Size: Aluminum case (separable lid): 5-3/4 H x 8-1/4 W x 7-3/4 D in (145 x 210 x 195 mm). Weight: 4.8 lb (2.2 kg). All specifications are nominal or typical at +23°C unless noted.
www.vishaymg.com 2
micro-measurements@vishay.com
Document Number: 11313 Revision 03-Feb-03
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