gAIn
This option adjusts the gain for the average velocity
calculation. Press ENTER from the initialization menu
to access the GAIN adjustment. Use UP and DOWN
to adjust the desired gain value (Range = 0.01 to 99).
Press ENTER to accept the value.
oFFSET
This option adjusts the offset for the average veloc-
ity calculation. Press ENTER from the initialization
menu to access the OFFSET adjustment. Use UP and
DOWN to adjust the offset value (Range = -1000 to
1000). Press ENTER to accept the value.
Note: Offset value is always in FPM.
Figure 16: gain Submenu
Figure 18: Zero Cutoff Submenu
Figure 17: offset Submenu
*
*
ESC
UP
DOWN
ENTER
SW2
SW3
SW4
SW5
ESC
UP
DOWN
ENTER
SW2
SW3
SW4
SW5
rUSKIn EFAMS ThErMAl DISpErSIon AIrFlow MEASUrIng SYSTEM InSTAllATIon InSTrUCTIonS
13
USIng ThE gAIn
AnD oFFSET SUBMEnUS
The average velocity is the average of each of the indi-
vidual sensor readings. If a system effect is causing an
issue with the EFAMS system, use the GAIN for a cor-
rection multiplier and the OFFSET as a correction (addi-
tion/subtraction) to the average velocity calculation.
In the event that something in the system is causing
measurement problems, adjust the GAIN or OFFSET
to adjust the EFAMS system to match a balancer’s
report. When a difference occurs between the output
of the Electronic Controller and the test and balance
report, adjust the gain. We recommend setting the
gain to 1 and taking multiple readings to determine
the difference. To calculate the gain, divide the test
and balance report by the output/reading of the Elec-
tronic Controller.
Adjusting the Gain
This feature applies a
multiplier across the entire scale.
If a balance report states a flow of 800 FPM, and the
EFAMS system reports 1,000 FPM, adjust the gain to
0.80 (800 / 1,000 = 0.80).
If a balance report states a flow of 1,000 FPM and the
EFAMS system reports 900 FPM, adjust the gain to
1.11 (1,000 / 900 = 1.11).
Adjusting the Offset
This feature applies a
value to the entire scale.
If a balance report states a flow of 1,000 FPM, and
the EFAMS system reports 800 FPM, adjust the offset
to 200 (1000 - 800 = 200).
If the balance report states a flow of 900 FPM and the
EFAMS system reports 1,000 FPM, adjust the offset
to -100. (900 - 1,000 = -100).
ZEro CUToFF
This option sets the zero velocity reference point.
Ensure that there is no airflow flowing through the
system, then access this menu to set the zero veloc-
ity reference point. The LCD screen displays CUTOFF
VALUE. Use UP and DOWN to scroll to values 40
FPM (0.20 mps) and above. Press ENTER to accept
the value.
The calculated velocity indicates zero when it reaches
the zero cutoff value.
CUTOFF
VALUE: 40 FPM (0.20 mps)
ZERO
CUTOFF
DISPLAY VELOCITY
OUTPUT FORMULA
*
ESC
UP
DOWN
ENTER
SW2
SW3
SW4
SW5
CUTOFF
VALUE: 65 FPM (0.33 mps)
