Unit improves calibration of quarter bridge amplifiers
Unit improves calibration of quarter bridge amplifiers
Keywords: Aerospace industry, Calibration, Measurement
The K 800 calibration unit for strain gage quarter bridges launched by HBM is said to calibrate eight channels simultaneously. The device is believed particularly useful for multi-channel measuring amplifiers, such as HBM's MGCplus, that must be calibrated regularly to ensure accuracy (Plate 1).
Plate 1The K 800 can be operated either by a PC connected using the USB port digital input
Multi-channel amplifiers are used for complex measurement applications needing higher channel counts, such as experimental stress analysis using single strain gages in the aerospace industry.
The K 800 comes with five calibration steps for amplifier imbalances of between +8 and 28 mV/V. The steps are individually balanced for each of the eight channels providing a precision resistor network to achieve high accuracy. The unit is fitted with LEDs on the front panel to show the device status at any time.
The calibration unit is described as an intuitive and easy to operate device that gives faster calibration than sequential calibration of measurement channels. Four versions of the device – 120, 350, 700 and 1,000 Ω– are available to meet the needs of the most popular nominal strain gage resistances.
The K 800 can be operated either by a PC connected using the USB port, or with a digital input. Adjustment of the calibration steps and the data acquisition can be made either manually or by using the PC running a controlling program. Checks on the calibration can be made quickly and easily.
An advantage of using the USB port is that cable snarls are reduced because no power supply pack is needed. A standard power supply pack is needed when the digital control input is used. The unit is designed with stackable metal housings allowing a number of different calibration units to be put on top of each other to save space.
Each K 800 is supplied with a DKD (German Calibration Service) certificate to ensure traceability of measurements to national standards. Cables that allow for either three- or four-wire circuits are supplied with the K 800 to connect the device directly to HBM's AP814 and AP815 quarter bridge amplifiers. These are used in conjunction with the ML801 basic measurement module.
Details available from: HBM UK. Tel: +44 (0) 20 8515 6100; Fax: +44 (0) 20 8515 6149; E-mail: info@uk.hbm.com; Web site: www.hbm.corn
