Fluke 875 manual High Alarm Circuit, Muting Stages of the Alarm Circuits

Page 36

Victoreen 875

Operators Manual

*Normal here signifies a small radiation signal so that the voltage at TP502 is close to zero volts.

NOTE

Both of the solenoids of the alert and high alarm circuits must operate for the CHANNEL TEST lamp to light.

The lighting of the CHANNEL TEST lamp does not of itself show that the remote alarm contacts have closed (See Relay Driver Schematic, drawing 876A-1-3B.) However, simple resistance measurements and reference to the relay driver schematic can assure that the output to the remote alarms is correct.

5.8 High Alarm Circuit

Troubleshooting in the high alarm circuit is completely analogous to that in the alert alarm circuit. Voltages may be slightly different because R513 may be set differently from R509. However, the high and low state should be recognizable.

5.9 Muting Stages of the Alarm Circuits

The muting stages of the alarm circuits (U502 pins 8, 9, 10 and pins 12, 13, 14) can cause trouble in two ways:

1.They can fail to mute the alarm circuits during the ECS Test, thus causing the alarms to sound when this is undesired.

2.They can mute the alarms when the alarms should sound. This is the more undesirable of the two possibilities.

If the CHANNEL TEST lamp lights when the CHANNEL TEST push button is pressed, the second possibility is eliminated. Conversely, if it does not light, malfunction in the muting stages is among the problems that must be considered in addition to those in the signal chain (also a light burn-out).

Critical voltages in one of the two muting OP AMPS of U502 are:

 

Normal (Low Signal Level)

Channel Test

ECS TEST

Pin 10

+2 V

+12.88 V*

+2 V

Pin 9

0 V

0 V

+12 V*

 

 

 

(Muting voltage)

Pin 8

+13.7 V

13.7 V

-9.8 V

*An especially high voltage (12.88 V) is place on pin 10 during the Channel Test to overcome the +12 V that is placed on pin 9 during the ECS Test. Muting is not desired during the Channel Test. Although there is only a slight possibility that an automatically initiated ECS Test would take place during a Channel Test, it is desired to eliminate even this slight possibility.

5-6

Page 35 Page 37
Image 36
Page 35 Page 37
Contents Victoreen High Range Containment MonitorFluke Biomedical Table of Contents Calibration and Test Procedures Specifications IntroductionGeneral Description Containment MonitorTemperature Operating 40 to 120F 4 to 49C Readout Module 876A-1Equipment Overview High-Range Containment Monitor DetectorRack Chassis Pull Box Assembly Cables/Connectors/PanelFlexible Tubing 878-12-30TAB Optional EquipmentHigh-Range Containment Monitor Typical Energy Response Curve Detector Typical Linearity Detector High-Range Detector, Recommended Installation Receiving InspectionProcedures, Warnings, and Cautions StorageBlank Installation InstallationReadout Module Pull BoxSpecifications for Cable Cable SealingCable and Wiring Installation Detector Test After InstallationSpecifications for Cable Detector Cable Inside ContainmentAncillary Wiring All Alarms on P2 Normal Operation Shelf StatePower 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 High Alarm Circuit Alert Alarm CircuitFail/Safe Circuit Recorders and Computer BuffersPen Clamp Panel Meter Action During ECS Test Meter at extreme lower end of scaleAction of Green Safe/Reset Light and Alarm During ECS Test Low Voltage Ramp GeneratorMonitoring Circuits of The ECS Board Block Diagram of ECS Test Safe/Reset Sub-circuits Muting Circuits of ECS BoardBlank Maintenance, Calibration, and Troubleshooting MaintenanceCalibration Test Procedure TP876A-1-108 Troubleshooting Signal Input Circuit Mother Board P/N 876-1-78, Schematic 876-1-3APreamplifierIMeter Board P/N 876A-1-86, Schematic 876A-1-3E Rear PanelTP501 TP502 +6.3 Test Point Normal Channel TestHigh 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 Outputs of U206 Pulse Generator on the ECS Board Operation of the Latch CircuitLatch Circuit Circuit assumed initially in Pass Condition Fail ConditionNOR Pin Voltage State CommentsCalibration 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