7252, 7252i Dual Output Digital Pressure Controllers

Adding to the flexibility of the Series 7252, two performance models are available: the Model 7252i that offers percent of reading performance further extending the capabilities of a single calibrator, or the Model 7252, that provides percent of full scale (FS) performance for each range.

The Model 7252i provides a precision of 0.005 % of Reading from 25 % to 100 % of each installed range. For pressures below the lower threshold of 25 %, the precision becomes 0.005 % of the 25 % value. Alternatively, the Model 7252 provides a precision of 0.003 % of FS for each installed range. Both models provide a one year stability of 0.0075 % of Reading allowing a one year calibration interval.

Both the 7252i and 7252 are available in a variety of pressure ranges. Choose from any pressure range combination from as low as 10 inH2O (25 mbar) up to 2500 psi (172 bar). For example, either the Model 7252 or 7252i can be configured with a lower pressure range of 10 psi (1 bar) and an upper range of 1 000 psi (70 bar). Or, a Model 7252i could include a 10 inH2O (25 mbar) range and 2 500 psi (172 bar) to cover very low and very high pressure calibration requirements. Only Fluke Calibration provides such a broad pressure range coverage factor in a dual output pressure controller.

For absolute mode calibrations, the Series 7252 can be supplied with a Barometric Reference option, or the Vacuum Reference option where a vacuum pump is connected to the reference port(s). While the former offers a high degree of convenience by allowing instantaneous transition from gauge to absolute mode, the Vacuum Reference option provides the ultimate performance solution, since it does not introduce the additional uncertainty of a secondary, barometric sensor. Instruments with the Vacuum Reference option include an on-board vacuum sensor to allow fully automatic zeroing when operating in absolute mode.

For applications where absolute calibrations are performed exclusively, permanent absolute ranges to 50 psia (4 bar) are available. The Series 7252 also provides negative gauge operation to support the calibration of a wide variety of test devices and applications.

The Series 7252 is a dual output pressure controller, which increases throughput, while providing maximum stability for each range. With simultaneous pressure control, it can actually perform two calibrations at the same time.

For Series 7252s configured with dual ranges between 10 (1 bar) and 1 000 psi (70 bar), the two test ports can be interconnected. The instrument will then auto range from the lowest to the highest sensor and vice versa. For performing single calibrations, this feature provides a high degree of performance over the full range. Increased throughput is also accomplished via the digital control valve technology, that ensures fast control speed with no overshoot. For example, each range will control in 10 % increments in 15 seconds, or less, into a 245 cubic centimeters (15 cubic inch) volume. No other controller combines this speed coupled with no overshoot control. For ease of use, the large, bright, active matrix color display provides the operator with menus that are presented in plain text with a logical navigation structure similar to all other Ruska digital pressure controllers and indicators, with multi-lingual support.

Automating pressure test and calibration

The Model 7252i and Model 7252 are easy to use and can automate your calibrations in several ways:

Step up/down: For calibrations where the increments are fixed intervals, enter a user-defined step value. The Series 7252 increases or decreases the pressure by the step amount with the jog dial—no lengthy keystroke sequences to program.

Sweep test: For simple exercising routines, as with dial gauges, enter a start value, a stop value and number of times to repeat the cycle. The Series 7252 will automatically exercise the device under test prior to the calibration run.

Computer interface: Every Series 7252 is provided with both an RS-232 and IEEE-488 interface, and all Series 7252’s syntax follow SCPI protocol for easy programming. Intecal, an off-the-shelf software package, is available in addition to a LabVIEW® driver, a free download. Firmware updates can also be performed over the RS-232 interface (updates can be downloaded from the website). A MET/CAL driver is also an available option.

Versatility to handle any pneumatic pressure calibration

The Series 7252 is versatile enough to handle almost any type of pneumatic pressure calibration.

Wide pressure range: The Series 7252 is available in a variety of full scale (FS) pressure ranges from 10 inH2O (25 mbar) to 2 500 psi (172 bar).

Pressure units/scales: Select from over fifteen standard units of measure, including inHg at 0 °C and 60 °F, kPa, bar, psi, inH2O at 4 °C, 20 °C and 60 °F, kg/cm2, mmHg at 0 °C, cmHg at 0 °C, and cmH2O at 4 °C, and two user defined units.

Head pressure: The Series 7252 automatically corrects for head pressure differences.

Autovent and autozero: With a few keystrokes, the Series 7252 will vent the test port to atmosphere or automatically zero itself (autovent is not applicable to permanent absolute models).

Protection of the device under test: Set upper and lower pressure limits to ensure protection of the device under test.