Azbil C1M - PV Low Limit Alarm Threshold; PV Filter; PV Hold

5-9
Chapter 5. Functions
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PV low limit alarm threshold
Item (bank) Display Description Initial value User level
PV input failure (under range)
type
(setup bank)
C 97
0: −10 % FS
1: −5 mV (valid only when C01 (PV input
range type) is set to 17 or 23.)
0 Simple,
standard,
advanced
This setting is valid when C01 (PV input range type) is set to 17 (sensor type: B)
or 23 (sensor type: PR40-20). If 1 (−5 mV) is set, the PV low limit alarm is not
triggered when the sensor is connected normally.
The PV low limit alarm is triggered if the sensor is connected in the wrong
direction.
PV limiting and PV low/high limit alarm (p.5-10) (for the lowest PV
that can be displayed)
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PV filter
The PV filter is a first-order lag filter used if the PV fluctuates sharply and
repeatedly out of control or if it flutters due to noise, etc. The larger the setting is,
the less frequently the PV changes.
Under normal circumstances, keep the filter at its initial value of 0.0.
Item (bank) Display Description Initial value User level
PV filter
(parameter bank)
FL
0.0: No filter
0.1 to 120.0 s
0.0 s Simple,
standard,
advanced
OUT = OUT
LAST
+ (IN − OUT
LAST
) / (T/T
s
+ 1)
IN: Input to the filter T: Filter setting (s)
OUT: Current filter calculation output Ts: Sampling cycle
(select from 0.05, 01, 0.3, 0.5 s)
OUT
LAST
: Previous filter calculation output
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PV hold
If the PV display is fluctuating, the display can be held steady in one of three ways
by assigning “PV hold,” “PV max. hold,” or “PV min. hold” to a digital input (DI).
PV hold:
The PV at a certain time is displayed and not updated.
PV max. hold:
The maximum PV is displayed.
The maximum PV is updated only if a new PV is greater than the displayed value.
PV min. hold:
The minimum PV is displayed.
The minimum PV is updated only if a new PV is smaller than the displayed value.
When the PV from a certain time, the maximum PV, or the minimum PV is being
displayed, the PV on the upper display flashes (blinks).