Fluke RUSKA 7252, Руководство пользователя

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RUSKA 7252
Users Manual
2-6
Barometric Sensor - Optional
For Simulated Absolute instruments, the Reference Port is monitored by a precision
barometric sensor. This sensor provides the barometric offset that allows the Gauge mode
Calibrator to function in an Absolute system.
A RUSKA 7252 must have a minimum full scale pressure range of 14.7 psig (101 kPa) in
order to be configured to operate in the simulated absolute mode using the barometric
reference sensor.
On RUSKA 7252s that have two gauge mode sensors with pressure ranges greater than
14.7 psig (101 kPa) and a barometric sensor option is installed, both channels are able to
operate in gauge or absolute modes. However, since the Barometric sensor is internally
only tied to one of the reference ports, it is recommended to externally tie the two
reference ports of both channels together and have them vented to atmosphere.
Absolute with Evacuated Reference – Optional
An option is available on the RUSKA 7252 that will allow a gauge mode instrument to
operate in the absolute mode by evacuating the sensors reference port with an external
high capacity vacuum pump. This option includes a vacuum sensor that is internally tied
to the reference port of the pressure channel that is configured with this option.
Note
For both channels to operate in this mode, each sensor must have a vacuum
sensor installed.
In gauge mode, the reference port is open to atmosphere. In the absolute mode, a vacuum
pump evacuates the reference port of the sensor. Once a vacuum level of less than
200 mtorr is achieved, the operator can zero the RUSKA 7252. The RUSKA 7252 would
zero the RUSKA quartz sensor against an internal vacuum sensor measuring this residual
vacuum level. This vacuum sensor continuously monitors and updates the pressure
reading based on the reference vacuum level.
Following the absolute zero, the channel would operate in the absolute mode. If the
RUSKA 7252 requires to control sub-atmospheric pressures, then a second vacuum pump
should be connected to the exhaust port for use in pressure control. It is not recommended
to use one pump connected to both the reference and the exhaust when operating in
absolute mode since the controller could cause an unstable reference vacuum.
Test Port
The Test Port connects the DUT to the Pneumatics Module on systems with a full scale
pressure range less than or equal to 1000 psi (7 MPa). The Test Port is isolated from the
DUT by a normally closed solenoid valve that is open during the Calibrator’s Measure,
Control and Vent modes and closed during the zeroing process. This test port isolation
valve is not utilized in higher pressure range Calibrators. The RUSKA 7252 has two test
ports, one for each pressure range in the system.
The Test Port is protected by a relief valve.