IDEC MicroSmart Pentra - Manual (Page 151)

A PPENDIX
9-4 FC5A MicroSmart PID Module User’s Manual FC9Y-B1283
Output Manipulated
Variable (MV)
Rate-of-Change The maximum change of the output manipulated variable in one second can be
configured.
PV Correction
If the sensor cannot be installed to the location of the control target, the
temperature measured by the sensor may deviate from the actual temperature of
the control target. When a target is controlled with multiple PID modules, the
measured temperatures may not match due to the differences in sensor accuracy
or dispersion of load capacities even though the set points (SP) of those PID
modules are the same. In such cases, the process variable (PV) of the PID module
can be adjusted to the desired temperature by using the PV Correction. The
process variable (PV) after PV correction is added should be within the control
range.
The process variable (PV) after PV correction can be calculated using the following
formula:
Process variable (PV) after PV correction = Process variable (PV) + (PV
correction value)
PV Correction Range:
When input is thermocouple or resistance thermometer: 0.1 to 100.0°C (°F)
When input is voltage/current: 1 to 1000
PV Filter Time
Constant
The PV filter function is a software filter to stabilize the process variable (PV)
affected by fluctuating processes, such as pressure or flow rate, by calculating
first-order lag of the process variable (PV).
Automatic
Cold Junction
Temperature
Compensation The PID module measures the temperature at the input terminal and maintains the
reference junction as if the reference junction was at 0°C or 32°F
Burnout
(Over Range)
When thermocouple input or resistance thermometer input is burnt out, the over
range bit of the operating status is turned on, and control output is turned off (when
output type is current, the output manipulated variable lower limit value is
outputted).
Control Range
When input is thermocouple:
Input range lower limit -50°C (100°F) to Input range +50°C (100°F
)
Range with a decimal point:
-(Full scale x 1%)°C (°F) to Input range +50°C (100°F)
When input is resistance thermometer:
-(Full scale x 1%)°C (°F) to Input range +50°C (100°F)
When input is voltage/current:
Linear conversion minimum value -(1% of linear conversion span)
to Linear conversion maximum value +(10% of linear conversion span)
PID Module
Standby
When the power is turned on, the PID module starts with the standby status. During
the standby, the control and alarm assessment are not conducted.
The control and alarm assessment are enabled when the control enable bit of the
operation parameters is turned on.
When the control mode is the program control and the power is restored, the PID
module resumes with the status at the time of the power failure.