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Section 5 Functions and Operations
■ F2: Absolute Ratio
5-10
N: Pulses per rotation
πd: Circumferential length per rotation
Example:
This example shows the prescale value and the prescale set
values for displaying the speed of a roller using a proximity sensor
that outputs five pulses per rotation.
Prescale value (α) = 1/5 = 2.0 × 10
Prescale value of Input A, X (mantissa): ps. ax = 2. 0000
Prescale value of Input B, Y (exponent): ps. ay = 10 -1
Measuring the Speed Ratio Between Two Rollers
Operation Configuration (Application)
• Basic Operation
The absolute ratio between the frequency of input A and the
frequency of input B is displayed as a percentage (%).
The measurement value can be obtained using the following
formula:
fb × β
× 100
D =
fa × α
fa: Frequency A (Hz)
α: Prescale value A
D: Absolute ratio (%)
* When fa x α = 0, an overflow will be displayed at the upper limit.
When fa x β = 0, 0 will be displayed.
Example:
This example shows the prescale values and the prescale set
values for displaying the absolute ratio between two rpm's using
two rotary encoders, each of which outputs 1,000 pulses per
rotation.
Prescale value of Input A (α) = 1/1,000 = 1.0000 × 10
Prescale value of Input B (β) = 1/1,000 = 1.0000 × 10
Prescale value of Input A, X (mantissa): ps. ax = 1. 0000
Prescale value of Input A, Y (exponent): ps. ay = 10 -3
Prescale value of Input B, X (mantissa): ps. bx = 1. 0000
Prescale value of Input B, Y (exponent): ps. by = 10 -3
−1
Encoder
HH
H
PASS
L
LL
Alarm outputs
fb: Frequency B (Hz)
β: Prescale value B
−3
−3
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