Fluke RUSKA 2482 User Manual page 12

RUSKA 2482
Users Manual
Software
With the Oil Isolation Valve open, there is zero differential across the Piston. Using the
hand pump a line pressure can be applied. This pressure is generated equally across the
Piston when the Oil Isolation Valve is open. Changes in the line pressure may result in a
small offset on the Balance. This effect is nulled by using the control program to tare the
offset and establish a zero datum at the given line pressure.
If the Oil Isolation Valve is closed and the thermal compensation enabled, the control
program will adjust the power to the temperature compensators to maintain a zero
reading from the Balance.
When a weight is added to the Mass Carrier, a force will be transferred to the Balance.
The resulting non-zero reading of the Balance will drive the controller to adjust the power
of the thermal compensators. The PID controller drives a change in the differential
pressure until the Balance is returned to the zero datum.
4
Mass Carrier
Piston
Balance
-Coarse Tare-
Balance Rd
Error
Fine Tare
Figure 2. System Operation Overview
Thermal
Adust
Oil
Line Pressure
Isolation
Sensor
Valve
Thermal
Adjust
PID
SetPoint
-nudge-
0.04g = 0.005mbar = 1ppm
-
Device
Under
+
Test
Line
Pressure
Display
gms03.eps