Toshiba LC531 Series Instruction Manual page 184

Appendix E Details of Variables
Item name
Low cutoff value
[0.01%]
Filter constant
[%]
Temperature
correction PV No
Pressure
correction PV No
Temperature
correction design
temperature
[°C]
Pressure
correction design
pressure
[KPa]
PV error
processing
definition
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6F8C1388
Table E-9 Parameter of [Indicator variable] (PV_PARA) (4/6)
Abbr.
LC At the time of instantaneous value processing, an instantaneous value
equal to or less than this value is treated as 0%. If this low cutoff value is
a negative value, low cutoff will not be performed.
Example: "10" indicates 0.1%.
● -2500≤LC≤12500
Note：When a differential pressure input is converted to a flow rate
signal with [Correction calculation code], square root extraction is
made. A small change of signal near 0% will be expanded and as
a result, PV value may fluctuate near 0V. In the case like this, a
positive value near 0 is given to the low cutoff value to eliminate
this fluctuation.
FT At the time of instantaneous value processing, the controller's signal
passes a low pass filter calculated in the following formula:
 0  FT  99, Output value = Input value  (1(FT/100) + Previous output
value ( FT/100)
Note: As shown in the formula above, the larger the value of FT, the
more a sudden fluctuation can be eliminated.
TM When process value is such as an air flow rate signal and correction
calculation by temperature is needed, PV No to show measurement
temperature should be registered.
 0: Unused / 1 to 128: Correction specified
PM When process value is such as an air flow rate signal and correction
calculation by pressure is needed, PV No to show measurement
pressure should be registered.
 0: Unused / 1 to 128: Correction specified
TDG ● When process value is such as an air flow rate signal and correction
calculation by temperature is needed, design temperature for reference
should be registered.
PDG ● When process value is such as an air flow rate signal and correction
calculation by pressure is needed, design pressure for reference should
be registered.
Note: The following correction calculation will be executed:
(In the case of correction calculation code: LNR = DP/F-PT
Output = Input ( (A/B) (D/C) )
A = TDG + 273.15
B = PV of correction input point (TM) + 273.15
C = PDG + 101.3
D = PV of correction input point (TM) + 101.3
PRD ● When an error (PDE or PVI) occurs in the signal source of process
value PV, PV processing error bit (PRE) will be set. One of the following
can be selected on how to capture this signal source error.
OR of sensor errors: PV processing error occurs if the signal of its own
Main sensor error only: Regardless of temperature/pressure correction
No sensor error: PV processing error does not occur even if sensor
error of its own sensor or sensor error of correction
point occurs.
Description
sensor or PV of temperature/pressure correction is
erroneous.
point, signal error of its own sensor only is
monitored to generate PV processing error
(PVE).
OIS DSP
○ ↓↑ ○
○ ↓ ○
↑
○ ↑ ○
○ ↑ ○
○ ↓ ○
↑
○ ↓↑ ○
○ ↓↑ ○