Bacharach Gas Pup Instruction

Bacharach Gas Pup Instruction Manual pdf 18 page image

Gas Pup12 Instruction 55-9002After checking for gas, allow the instrument to sample fresh air until theLCD shows a very low ppm reading. This will help prolong sensor life bypurging the sensor chamber of combustible gas.Auto-RangingThe Gas Pup incorporates an auto-rangingfunction that automatically switches thedisplay between ranges when a range limit isreached. This avoids manual switching, andassures, in conjunction with the range display,that accurate readings are provided at alltimes. The range selected by the instrument isindicated by a pointer that appears in theRANGE window (see Figure 7).When a reading in the PPM range exceeds2,500 ppm (equal to 0.25% by volume, bargraph at full scale), the display will automati-cally switch to the LO% range, covering from0.2% to 5.0%. This change will be instanta-neous. But if the reading is close to 2,500 ppm,observe that the display may flicker betweenranges for a few seconds.When the LO% reading exceeds 5.0%, thedisplay automatically transfers to its HI% range. This transfer takes afew seconds to allow the detector to stabilize in the new range.Auto-ranging from HI% to LO% occurs when the reading falls below 5.0%for more than 5 seconds. The 5-second delay is to prevent nuisance rangetransfers.Fixed HI% RangeManual selection of the HI% range may bemade to avoid any delay caused by auto-ranging(for example in barhole testing), and to retainthe highest reading shown on the bar graph. Tolock the instrument in its HI% mode, momen-tarily press the key. Once auto-ranging hasbeen overridden, the instrument will remain inthe HI% range until the key is pushed again.OperationHI%LO%PPMRANGEHI%LO%PPMRANGEHI%LO%PPMRANGEPPM RangeLO% RangeHI% RangeFigure 7.Range DisplayHI%LO%PPMRANGEHI% RangeFigure 8.Fixed High Range