Yokogawa Value Series FX1000 - Manual (Page 91)

3-18 IM 04L21B01-01EN
• Example 2: Number of Pulses per Minute
Using the FX1002 (scan interval set to 250 ms), count the number of pulses received
by pulse input terminal 6, and calculate the number of pulses per minute.
Number of pulses
per second
101ch
102ch
Number of pulses
per minute
Pulse input
Scan interval
(250 ms)
Time
(Moving average over a minute)
(60x)
Expression
Assign the computation channel as shown below and set the expressions. Set the
span lower/upper limit and unit according to the application.
Channel Expression Description
101 Q6 Number of pulses per second
102 101*K01 Number of pulses per minute
Channel Value Description
K01 60 Coefficient for converting the number of pulses
per second to the number of pulses per minute
Channel Rolling average Description
101 Sampling interval: 1s Moving average over a minute
Number of samples: 60
Channel
The computation is performed in order from the channel with the smallest channel
number in one scan interval.
Use a channel of a channel number larger than that of the channel counting the
number of pulses per second for the computation channel that is to calculate the
number of pulses per minute.
• Example 3: Reset When the Pulse Sum Value Exceeds a Certain Value
Reset the sum value when the pulse sum value exceeds a specified value (reset
value) and carry over the value exceeding the reset value to the sum after the reset.
Count the number of resets and calculate the total sum value up to that point.
Expression
Assign expressions to the computation channels as shown below and set the
constants.
Channel Expression Application
101 ((102+P01).GE.K01)+101 Pulse sum value reset count
102 CARRY(K01):TLOG.SUM(P01) Pulse sum value
103 K01*101+102 Total sum value
Symbol Description
P01 Counts the number of pulses per scan interval.
K01 Constant. The reset value. The sum value is reset when this value is exceeded.
3.10 Counting Pulses (/PM1 Option)