Rapiscan TSA TPM-903B Operation And Service Manual - page 16
TSA TPM903 Operations and Service Manual
Doc: # 5058 Rev. A
_____________________________________________________________________________________________________________________
_____________________________________________________________________________________________________________________
This document is the exclusive property of Rapiscan Systems.
Unauthorized use or distribution is strictly prohibited
10
2. Manual adjustment: At the "ADJUST ULD/LLD" menu, the discriminators may be adjusted
one step at a time while observing the count from both detectors.
The following keys are used:
1 increments the LLD by one step (approximately 0.0098 volts)
7 decrements the LLD by one step
3 increments the ULD by one step (approximately 0.0196 volts)
9 decrements the ULD by one step
When the settings are satisfactory, press the pound (#) key to accept the settings.
Pressing the asterisk (*) key will load the default discriminator settings: LLD = 0.098 and ULD =
5.040.
3.4.2. FUNCTIONS
1. SHOW COUNT: Displays detector counts
2. VARIANCE: Performs variance test on all detectors
3. CLEAR G-CNTS: Clears the counter of recorded gamma alarms
4. F-ALARM TEST: Displays the number of alarm comparisons vs. the number of alarms
5. SYSTEM ID: Assigns an identification number to the system
6. PROFILING: Turn ON or OFF an ASCII data string to the Ethernet and RS-232 outputs
7. CALIBRATION: Automatically adjusts each detector to achieve the proper CPS.
8. RESTORE CAL: Restores the factory calibration high voltage values.
3.4.2.1. SHOW COUNT
Displays detector counts, in CPS, updated once per second. All alarms are disabled in the show
count mode. Press the pound (#) key to exit the show count mode.
3.4.2.2. VARIANCE
Performs a variance test on all detectors. The system runs 15-second variance passes. In the
TPM-903B system, Rapiscan recommends running five 15-second passes. After five passes all
variance readings should be less than 0.10. Refer to Appendix A for further detail on the variance
test and the formulas used. Press the pound (#) key to terminate the variance test. Perform a
variance test and a walk-through test with a source (see Section 4) before the unit is put into
operation. For more information and recommended settings for different SNM types call
Rapiscan’s engineering staff.
3.4.2.3. CLEAR G CNTS:
The SC-770 counts the number of occupancies and alarms since it was turned on. These numbers
are displayed here. The counter may be cleared by pressing
<1>, any other key exits this mode
without clearing the counters.