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©

 2019 CDI Meters, Inc. 

10.19 

Installing the Meter 

Make sure the probes are clean. If there is any oil or dirt on them, clean them 

with alcohol or a similar degreaser. Insert the band clamps into the slots provided 

for them and then insert the probes into the holes in the pipe, with the flow arrow 

pointing in the proper direction. Engage and tighten the band clamps. 

Wiring the Meter 

The meter requires 24 Volt dc power. Insert the power-supply cable through the 

grommet at the bottom of the meter. Connect the positive lead to the dc+ 

terminal, the negative lead to the dc- terminal and the shield, if one is present, to 

the gnd terminal. If you are using the wall-plug supply and adaptor cable 

provided by CDI, the band-marked lead (not the printed lead) is positive. 

Programming the Monitoring Functions 

The meter has four display modes: rate, minimum, average and total. The display 

is controlled by a button on the underside of the meter. Pressing the button 

repeatedly will cycle the display through the four modes; LEDs above the digital 

display indicate which mode is active; when no LED is lit, the meter is in the rate 

mode. 

Minimum and Average Modes 

The minimum and average functions look back over periods of time specified by 

the user. Each is based on 360 samples taken over the specified period of time. 

Minima and averages are calculated and stored for groups of 36 samples, so the 

displayed results are updated at an interval of one tenth of the period specified 

by the user. Thus, if the average is computed over 0.1 hour (six minutes), the 

flow will be sampled every second and the display will update every 36 seconds. 

Please note that, since the minimum and average are based on data stored in 

memory, they will not be meaningful until the specified period has elapsed. 

Total Mode 

Cumulative air usage is displayed in thousands of cubic feet, or in cubic meters. 

The total is not resettable. 

Filter 

A simple digital filter is provided for situations in which flow is continuously 

varying and a steady, filtered display is useful. If the filter factor is programmed to 

zero (see below) there is no filtering. If it is one, the current value is averaged in 

equal parts with the previous filtered value. If it is two, one quarter of the present 

value is added to three quarters of the previous filtered value, and so on, with 

factors available up to six. Filtered values are used in calculating minima and 

Summary of Contents for CDI 25 Series

Page 1: ...ty times the diameter at a minimum Five diameters of straight downstream pipe is sufficient unless the meter is immediately upstream of something that would restrict the flow such as a valve Select a location that meets these requirements and also provides good visibility Preparing the Holes When the holes are drilled metal shavings will enter the pipe Make sure that filters or other provisions ar...

Page 2: ...er is in the rate mode Minimum and Average Modes The minimum and average functions look back over periods of time specified by the user Each is based on 360 samples taken over the specified period of time Minima and averages are calculated and stored for groups of 36 samples so the displayed results are updated at an interval of one tenth of the period specified by the user Thus if the average is ...

Page 3: ...ithout a decimal point on the right The letters indicate which parameter is being programmed the digits indicate the current value of the parameter When a three digit parameter is displayed one of the letters will be overwritten To advance the parameter press and release the button to advance the parameter rapidly press and hold the button To advance to the next parameter just wait Time is display...

Page 4: ...er shall be free from defects in materials and workmanship when given normal proper and intended usage for three years from the date of purchase During the warranty period CDI will repair or replace at its option any defective product at no cost to the buyer The foregoing warranty is in lieu of any other warranty express or implied written or oral including any warranty of merchantability or fitne...

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