Fluke 875 manual Function Description, Functional Description, Readout Module 876A-1

Page 21

Function Description

Functional Description 4

Section 4

Function Description

4.1 Functional Description

High-Range Containment Monitor Detector 877-1

The high-range containment monitor detector is an ion chamber detector that has the appearance of a six-inch diameter domed cylinder about seven inches long, mounted on an L shaped bracket. Inside the cylinder are two flange-mounted electrodes consisting of 31 flat, disk-shaped plates, each about four inches in diameter, stacked, and mounted on disk rods. The 31 disks form two groups, interleaved with each other, 16 collection disks and 15 signal disks. Because of the interleaving, they appear as only one stack, but the collection disks are mounted on three collection disk-posts and the signal disks on three signal disk-posts. Spacers on the posts keep the disks separated so they do not come in contact, and clearance holes in the disks allow posts of the opposite polarity to pass through without contact. The assembly has the appearance of a large air capacitor. The mounting posts are attached to the mounting flange through insulating spacers, so the flange and housing will be neutral with respect to the charges applied to the electrodes. The collecting diskposts are elongated beyond the last collecting disk to support a cup-shaped liner having the same potential as the collecting disks, thus becoming part of the collector.

The whole assembly is covered by the six-inch diameter housing which contacts only the neutral mounting flange. The mounting flange is pierced by three holes. One hole supports the exhaust tube used for exhausting and back filling the chamber. The other two support two 2-pin connectors, one for each electrode. One pin in each pair is connected to the neutral mounting flange. When the coaxial signal cable is connected to this connector, the cable shield is connected to the neutral pin.

The entire chamber is filled with a mixture of helium (2%) and nitrogen at atmospheric pressure and sealed.

CAUTION

The seal on this chamber must not be broken. To do so would alter the calibration and specified energy response of the system.

4.2 Readout Module 876A-1

NOTE

Drawings 876A-1-3H and 876-1-3A serve as interconnecting diagrams for tracing signals between printed circuit boards. In addition, drawing 876-1-3A contains the main power supply

4-1

Page 20 Page 22
Image 21
Page 20 Page 22
Contents High Range Containment Monitor VictoreenFluke Biomedical Table of Contents Calibration and Test Procedures Introduction SpecificationsGeneral Description Containment MonitorReadout Module 876A-1 Temperature Operating 40 to 120F 4 to 49CEquipment Overview High-Range Containment Monitor DetectorRack Chassis Cables/Connectors/Panel Pull Box AssemblyFlexible Tubing 878-12-30TAB Optional EquipmentHigh-Range Containment Monitor Typical Energy Response Curve Detector Typical Linearity Detector Receiving Inspection High-Range Detector, Recommended InstallationStorage Procedures, Warnings, and CautionsBlank Installation InstallationReadout Module Pull BoxCable Sealing Specifications for CableDetector Test After Installation Cable and Wiring InstallationSpecifications for Cable Detector Cable Inside ContainmentAll Alarms on P2 Normal Operation Shelf State Ancillary WiringPower Connections P1 Computer & RecorderOperation OperationVictoreen Function Description Functional DescriptionReadout Module 876A-1 Negative Power Supply High Voltage Power Supply Normal Operation non-ECS Test FAIL/SAFE Comparison Circuit on Power Supply BoardOperation of High Voltage Supply During ECS Test Alert Alarm Circuit High Alarm CircuitFail/Safe Circuit Recorders and Computer BuffersPen Clamp Meter at extreme lower end of scale Panel Meter Action During ECS TestAction of Green Safe/Reset Light and Alarm During ECS Test Low Voltage Ramp GeneratorMonitoring Circuits of The ECS Board Block Diagram of ECS Test Muting Circuits of ECS Board Safe/Reset Sub-circuitsBlank Maintenance, Calibration, and Troubleshooting MaintenanceCalibration Test Procedure TP876A-1-108 Troubleshooting Mother Board P/N 876-1-78, Schematic 876-1-3A Signal Input CircuitPreamplifierIMeter Board P/N 876A-1-86, Schematic 876A-1-3E Rear PanelTest Point Normal Channel Test TP501 TP502 +6.3High Alarm Circuit Muting Stages of the Alarm CircuitsNormal Low Signal Level Channel Test ESC Board P/N 876A-1-92, Schematic 876A-1-3D Wave Shapes on the Electronic Check Source Board Starting With Pins M and P on the Power Supply Schematic Overall Fail Circuitry Associated with the ECS TestStarting With Terminal H on Relay Driver Board Operation of the Latch Circuit Outputs of U206 Pulse Generator on the ECS BoardCircuit assumed initially in Pass Condition Fail Condition Latch CircuitPin Voltage State Comments NORCalibration and Test Procedures Blank Cable and Pull Box Procedures Cable and Pull Box ProceduresVictoreen Applicable Drawings and Bill of Materials Applicable DrawingsDocument Number Description Detector Cable Out of Containment Applicable Bill of Materials Fluke Biomedical
Top Page Image Contents