Dwyer TM2 - Manual (Page 6)

Making minor changes in calibration (of the display)
If you notice a small error in the display of either rate or total flow,
a small change in the Rate or Totalizer Multiplier may correct the
problem. To establish the error, you must provide a constant,
steady signal to the Model TM2 Display. This usually means
putting a steady, constant flow through the Flo-Sensor that the
display is connected to. Higher flows (within the flow range of the
Flo-Sensor) will allow you to more accurately correct the error.
To recognize the error, the display should be in normal operating
mode, not programming mode. With a constant signal, the Model
TM2 will display a constant rate and will totalize flow steadily. If
you are experiencing a minor error in the Rate display, set the
display to show rate (see Operating Instructions). If you are
experiencing a minor error in the Total Flow display, then set the
display to show total flow.
With the display in the correct mode, measure the amount of flow
passing though the Flo-Sensor in exactly one minute. Compare
this to what the Model TM2 shows. If there is a small error,
correct it by dividing the actual flow by the indicated flow. Take
that result and multiply it by the factor located in screen #1 or
screen #3, the Totalizer Multiplier and Rate Multiplier screens,
respectively. If you are correcting a minor error in the Totalizer
function, then multiply it by the factor in screen #1. If you are
correcting a minor error in the Rate function, then multiply the
number by the factor in screen #3. The final result should be
programmed into the appropriate screen as outlined in Section 3.
d. No decimal points should need to be moved for corrections of
minor errors.
As an example, a Model TM2 display indicates a flow rate of 5.0
L/min when the flow rate is actually 5.2 L/min. If you divide 5.2
by 5.0, you get approximately 0.962. The Rate Multiplier in
screen #3 is currently 1.345. If you multiply 0.962 by 1.345, you
arrived at 1.294. The number should then be programmed into
screen #3, and the minor error will be corrected.
F-41-TM2:Model PHO-1 8/24/10 11:51 AM Page 6