Yokogawa ADMAG CA - Manual (Page 50)

IM 1E8B0-01E
6-13
6. FUNCTION AND DATA SETTINGS
• Signal processing procedures:
The function sets a certain upper and lower limit (rate limit value) for first order delay
response values of flow rate data obtained in a previous sampling. If currently
sampled flow rate data exceeds or goes below the limit is regarded as current flow
rate value. Signals whose protruding portions show the same trends during a certain
number of sampling times (dead time) are identified as flow rate signals.
Example 1: Step Input
1%
10%
Step Signal
Flow rate value
after rate limiting
Flow rate value after
damping
(3)
(1)
(2)
9 18
(4)
63.2%
Input: 0 to 10%
Damping time constant: 3 sec.
Dead time: 3 sec.
Rate limit value: 1%
Dead time: 3 sec.
Sampling times
(1) Shows 1% response cause of excessive signal beyond the rate limit. However, actual
output is under damping that described by a solid line.
(2) Shows the flow rate signal (1%) of just after damping calculation (1) and rate limit
value.
(3) This signal is recognized as a flow rate signal since it does not return to within the
rate limit value within the dead time.
(4) The output signal follows the damping curve and tracks the step signal.
Example 2: Slurry Noise
Slurry Noise
Flow rate value after rate limiting and damping.
Flow rate value after
rate limiting
Dead time: 1 sec.
Time
+1%
–1%
Input: 0 to 10%
Damping time constant: 1 sec.
Dead time : 1 sec.
Rate limit value: 1%
The left figure shows that the slurry
noise is not a flow rate signal.
Display Description
Set a rate limit function value in parameter number "N3".
Range of possible settings : 0 to 10%.
set the dead time in parameter number "N4".
Range of possible settings : 0 to 15 seconds.
Default: 5%
Default: 0%
(rate limit function off)
*Item "n" can be opened by entering "55" in parameter number "L2".