IDEC FC5A-F2M2 User Manual page 103

C PID M
ONFIGURING ODULE USING
(12) Control Register+33: Set Point (SP) Rise Rate
(13) Control Register+34: Set Point (SP) Fall Rate
When the set point (SP) is widely changed, this function makes the set point (SP) change gradually. The
rising/falling span of the set point (SP) in 1 minute can be configured.
When the set point (SP) is changed, the set point (SP) is gradually changed from the original set point (SP) to
the new set point (SP) with the configured ratio (°C/minute, °F/minute). When the control is started, the set
point (SP) is gradually changed from the process variable (PV) to the set point (SP) with the configured ratio
(°C/minute, °F/minute). In the fixed value control mode, this function is used to configure the desired
temperature gradient until the process variable (PV) reaches the set point (SP).
This function is disabled when the set point (SP) rise/fall rate is 0.
(14) Control Register+32: Output Manipulated Variable Rate-of-Change
The maximum change of the output manipulated variable in one second can be configured. This function is
disabled when the value is 0.
In the case of heating control, when there is a large deviation between the process variable (PV) and the set
point (SP), the output immediately changes from off to on as shown in the diagram below (Normal Output). By
configuring the output manipulated variable rate-of-change, the maximum change of the output manipulated
variable (MV) in one second can be changed as shown in the diagram below (Output When Output
Manipulated Variable Rate-of-Change is Configured).
This function can be used for a high temperature heater (used at approximately 1500 to 1800°C) which has to
be heated gradually, as the heater can be burnt out if the power is supplied rapidly.
Normal Output
ON
OFF
(15) Control Register+61: Output ON/OFF Hysteresis
Output on/off hysteresis can be configured. When the control action turns from on to off and vice versa, the
span between on and off positions is called output on/off hysteresis.
If the output on/off hysteresis is narrowed, the control output switches to on or off even by a slight variation of
temperature at around the set point (SP). This frequent on/off shortens the output relay life and may negatively
affect the connected equipment. To prevent that harmful effect, the hysteresis is provided for on/off control
action.
Output on/off hysteresis can be configured only for the ON/OFF control action (when the proportional band or
proportional gain is 0).
(16) Control Register+21: Manual Mode Output Manipulated Variable
The output manipulated variable (MV) for the manual mode can be configured.
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Output When Output Manipulated Variable Rate-of-Change is Configured
100%/sec 20%/sec
1 second 5 seconds
FC5A MicroSmart PID Module User's Manual FC9Y-B1283
10%/sec
10 seconds