AI-Tek Instruments TACHTROL 3, Инструкция по эксплуатации, Страница: 10 / 30

2. Dual Channel
A. Find the number of pulses per revolution (PPR) produced by the gears or targets
being monitored by the speed sensors.
B. Calculate the scaling factors by applying the number of PPR’s to the appropriate for-
mula for the engineering units you are displaying.
For RPM the formula for finding the scaling factor is:
60
PPR = Scaling Factor
Suppose you are using Channel A to measure RPM from a 48 tooth gear and Channel
B to measure RPM from a 90 tooth gear. The formulas read:
60 = 5
Channel A: Scaling Factor = 48 = 4
60 = 6
Channel A: Scaling Factor = 90 = 9
The formulas for GPM; FPM; IPM; IPS; and FPS are given in the previous section for single
channel instruments. Please be sure to read the note at the end of that section.
4.1.2 Other Applications for Scaling to Other Engineering Units
The general formula is:
D
ISPLAY
V
ALUE
S
CALING
F
ACTOR
= I
NPUT
S
IGNAL
F
REQUENCY
To solve this problem:
1. Pick a display value within the range of your operation.
2. Calculate the Input signal frequency produced by the speed sensor at the display value
you’ve picked.
Frequency is simply the number of electrical “pulses” produced by the sensor in one second.
All AI-Tek sensors produce 1 pulse each time a gear or target tooth passes in front of the sen-
sor. You wilI need to calculate how many pulses per second are created by the sensor when
your machinery is operating at the display value you’ve picked.
3. Divide the display value by the input signal frequency.
4.2 SELECTING THE MATHEMATICAL FUNCTIONS (C
11
)
Select the mathematical functions from the menu below. You select and route a mathematical
function to an output by placing the number to the left of the function in a digit of the Function
Constant (C
11
). For a complete explanation of how to enter the functions see Section 4.4.
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