Medivance Arctic Sun 2000, Service Manual

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CHAPTER 5 CALIBRATION AND SAFETY CHECK
5.1 The Calibration and Test Unit
The Model 2000 Calibration and Test Unit (CTU) is an instrument that is used to calibrate the Model
2000 Control Module. It is a hand sized unit that connects directly to the fluid delivery line port, taking
the place of the Model 2000 fluid delivery lines and pads.
5.1.1 Basic CTU Operation
The CTU is used as an external stimulus and measuring device by software embedded in the Control
Module. The CTU contains precision resistors, a sensor for measuring water temperature, and water
heaters that are calibrated at the factory. The factory calibration data is listed on the CTU and is
entered into the Control Module during the calibration process. The resistors simulate several patient
temperatures. After a warm-up period, the simulated temperatures are first applied to the patient
temperature inputs to temporarily calibrate each channel. This calibration is temporary in the sense
that it is used to perform the balance of the testing. It is not saved by the Control Module until the
operator accepts it. Once the patient temperature channel's accuracy has been established, the
Temperature Out circuit and the CTU’s temperature sensor are connected to the Control Module’s
Patient Temperature inputs, in turn. The Control Module then circulates water through the CTU at
various temperatures. In this way the patient temperature channel can then be used to check and
calibrate the accuracy of the Control Module's internal water temperature sensors and circuits.
The fluid path in the CTU is designed to allow a specific flow rate at the operating pressure. Since
the Model 2000 controls the inlet pressure at a constant -7 psi, a crosscheck of flow and pressure
measurement accuracy can be obtained. The inlet pressure offset is zeroed during the initial warm-
up period.
The CTU water heaters are used to slowly raise the system water temperature above its high
temperature limits in order to verify correct operation of the Control Module’s safety systems. The
test unit heaters are thermally and electrically protected, and are only powered while pressing the
Heater Power Switch.
5.1.2 Warnings
ƒ The CTU must not be used on equipment connected to a patient.
ƒ Do not use the Calibration and Test Unit in the presence of flammable agents because an
explosion or fire may result.
ƒ Anyone performing the procedures must be appropriately qualified.
ƒ Carefully observe the Calibration and Test unit for fluid leaks before and during use. Leakage
may result in lower flow rates or an electrical shock hazard.
5.1.3 Electrical Ratings
ƒ Voltage: 115V/60Hz or 230V/50Hz
ƒ Current: 4.5A or 2.25A
ƒ Fuse: 6.3A Slow Blow (2)
ƒ Power: 500W