Direct Scientific DSM-502, Руководство по эксплуатации и техническому обслуживанию

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WBJI DSM-502
PAGE 6
5.0 OPERATING INSTRUCTIONS
5.1 BEFORE OPERATION
5.1.1 The DSM-502 HIGH VOLTAGE and GAIN are adjusted to the operating characteristics of
the probe supplied with the meter. The GAIN (input sensitivity) is adjusted to 0.050 v-pp
with an input sensitivity of 0.050 v p-p. These high voltage and gain settings are satisfactory
for operation with the many probes but can produce large errors if the DSM-502 is not
calibrated with the internal probe. Refer to the MAINTENANCE SECTION 6.2 for High
Voltage adjustment procedure and SECTION 6.3, 6.4 for the calibration of the system. Be
sure the R/Sv and the CPM/CPS switch has be set to the proper units before calibrating the
system. Figure 4 shows the location of the switch on the LCD pc board.
5.1.2 NO OTHER CHECKS ARE NECESSARY PRIOR TO OPERATING THE DSM-502
EXCEPT TO OBSERVE THE DIAGNOSTIC INDICATORS IN THE LCD DISPLAY
WHEN THE UNIT IS FIRST TURNED ON. The internal microprocessor analyzes the
internal parameters for a few seconds when the instrument is first turned on and during the
instruments operation. All range, battery & probe diagnostic are turn on momentarily
during start-up to show they are working. The display then reverts to NORMAL operation.
The diagnostic circuits connected to the BATT & PROBE indicators continuously monitor
the Circuitry for out of range operation. Battery voltage below 6.8vdc will light the BATT
Symbol on the LCD. SATURATION of a GM detector in high radiation fields will light the
FAULT light. Exceeding the normal operating range of a probe in the DOSE mode will
result in an audible beep every few seconds until the radiation field is reduced within the
operating limits for the probe.
5.2 INSTRUMENT OPERATION
5.2.1 Adjust the MAIN SELECTOR switch to RATEMETER for normal ratemeter type operation.
5.2.2 Depress the SPEAKER/ZERO towards SPEAKER if a audible “tick” for each input pulse is
desired (to turn of the “tick” depress the switch again towards SPEAKER)
5.2.3 Select the mode of operation CPM or DOSE (BASED ON CS 137 CALIBRATION) with the
CPM/DOSE MODE SWITCH set to DOSE includes linearization & DEAD TIME for the
probe. Both corrections are automatically incorporated in the calibration procedure for each
probe.
NOTE: ALL PROBES USING GM DETECTORS CAN BE DOSE CALIBRATED REFERENCED
TO Cs137. ONLY SOME OF THE PROBES USING SCINTILLATION DETECTORS
CAN BE DOSE CALIBRATED, PRIMARILY FOR MICRO R MEASURMENTS. MOST
SCINTILLATION PROBES MUST BE OPERATED IN THE CPM OR COUNT MODE IF
THEY ARE NOT DOSE CALIBRATED.
5.2.4 The LCD READOUT can display the probe signals in CPM, COUNTS, ROETGEN AND
SEIVERTS. When calibrating the system the decision to operate in CPM or CPS and
ROETGEN OR SEIVERTS MUST BE MADE AND THE APPROPORIATE SWITCHES
ADJUSTED BEFORE THE SYSTEM IS CALIBRATED. FIGURE 4 SHOWS THE
LOCATION OF THE R/Sv SWITCH AND THE CPM/CPS SWITCH.
5.3 INSTRUMENT OPERATION – COUNT
5.3.1 The count mode will count each individual pulse from the probe and display the count on the
LCD. The system will be activated when the MAIN SELECTOR SWITCH is placed in the
COUNT position. To start the counter from 0 counting time depress the ZERO SWITCH
FOR AT LEAST 3 SECONDS. The COUNTING will appear and continue until the count
cycle is complete. When the counting period is complete COUNT will appear indicating the
cycle is complete. To start another count cycle depress the ZERO switch FOR AT LEAST 3
SECONDS. If the system is adjusted to 0 seconds counting time then the system will
continue to count as long as the MAIN SELECTOR SWITCH IS IN THE COUNT
POSITION. See how to set count time.