When I put the SEI Inspector USB in total mode, why does it not accumulate the total counts? Posted on April 18, 2018 The latest version of the SEI Inspector USB requires that the timer be set prior to accumulating total count. To take a timed count, follow these steps: 1. With the SEI Inspector operating, set the Mode switch to Total/Timer. The display shows 0 and Total in the upper left portion of the display. 2. Press the SET button on the end panel to set the time for your count. You will see the hourglass, and the most recent timing period used. The first time you use the timer, the setting is 00:10 (ten minutes). 3. Use the + and – buttons to set the timing period. The timed period can be for 1 to 10 minutes in one minute increments, for 10 to 110 minutes in 10-minute increments, or for 2 to 24 hours in 1 hour increments. 4. Press the SET button. The SEI Inspector starts totaling the counts it registers, and the numeric display is updated each time a count is registered. The hourglass indicator flashes during the timed period. During the counting period, if you want to see how many minutes remain, press and briefly hold the SET button. The display counts down from the time setting in hours and minutes to zero. For example, if the display shows 00:21, then 21 minutes remain. 5. At the end of the timed period, the SEI Inspector beeps 3 times and repeats the beeping 3 times. The number displayed is the total count and the hourglass will stop flashing. 6. To find the average dose rate for the timed period, divide the total by the number of minutes. The average count is in counts per minute. To convert to mR/hr for Cesium-137, divide by 3340. 7. Move the Mode switch to one of the dose/rate modes to return to normal operation. If you move the Mode switch to one of the dose/rate modes while the SEI Inspector is taking a timed count, the timed count will continue. 8. To reset the timer to take another timed count, press the SET button to set the time for another count. 9. Press the SET button a second time and the SEI Inspector will start totaling the counts it registers, and the numeric display is updated each time a count is registered.