Operation

Operation Instructions 3

A reset error will not occur for ion chambers calibrated in dose rate units (i.e. Brachytherapy chambers) since the measurement is primarily concerned with amps or dose rate.

3.9.15 Reset Error (With Automatic Leakage Compensation Enabled)

The following discussion is only applicable when automatic leakage compensation is enabled and the ion chamber is calibrated in Coulombs.

Holding the RESET/MEASURE button while on the Measurement screen causes the Model 35040 Therapy Dosimeter to reset the electrometer, zero all readings, and restart the measurement process. When an exposure is detected immediately following the reset that was not present prior to the reset, the instrument displays the reset error message shown in Figure 3-31.

ADCALC

Internal Reset Error

Press RESET/MEASURE

and Repeat Exposure

Figure 3-31. The Measurement screen showing the Reset Error message

To remove the error message, end the exposure and hold the RESET/MEASURE button. Wait a few seconds for the instrument to complete the reset and repeat the exposure.

3.9.16 Annunciators

The top line of the display is dedicated to status annunciators. The Model 35040 Therapy Dosimeter continuously monitors the ion chamber bias and battery voltages. If either one of these values is outside the specified range, the Model 35040 displays an annunciator to indicate the error. Table 3-2 specifies these annunciators and specifies the annunciators that may appear on the top line of the display.

Table 3-2. Annunciators

Annunciator

Condition

 

 

??Bias

No bias measurement possible since the electrometer is not ready

 

 

ADC

Air density correction in use (only applicable to radiological

measurements)

 

ALC

Automatic leakage compensation enabled

 

 

LoBat

Low Battery voltage

 

 

LoBias

Low Bias voltage

 

 

HiBias

High Bias voltage

 

 

OvAmps

Overranged current

 

 

Rst

Resetting electrometer

 

 

Tmr

Timer in use

 

 

WAIT Bias Not Ready

The dosimeter is setting the bias

 

 

WAIT System Not Rdy

The dosimeter is resetting the electrometer (only applicable when

automatic leakage compensation is enabled)

 

Figure 3-32 illustrates the locations of some annunciators. The battery, bias, and overranged current annunciators appear at the same location, and the instrument alternates the displaying of each annunciator when more than one is applicable.

3-19

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Fluke 35040 manual Reset Error With Automatic Leakage Compensation Enabled, Annunciators, Annunciator Condition