Yokogawa Data Acquisition with PID Control CX2000 - Manual (Page 46)

1-34
IM 04L31A01-01E
Shutdown Function ON/FF (can be specified only during manual mode using 4- to 20-
mA current output)
The shutdown function closes the control value fully (set the output to 0) exceeding the
dead band of the control valve positioner. When this function is turned ON, the control
output is set to 0 mA if the manual control output becomes –5.0%.
Manipulated
output
20.0 mA
–5.0%
100.0%
Output
display value
3.2 mA
4.0 mA
0.0 mA
Note
The “output high-limit alarm” is not activated even if the control output becomes 0 mA due to
shutdown.
Manual Reset Value (valid only when the integral action is Off)
The manual reset value is the output value when the PV is equal to the SP. For example, if
the manual reset value is set to 50%, the output value is set to 50% when PV = SP.
Selectable range of manual reset value: –5.0 to 105.0%
Control Direction
The control action direction defines the direction (increase or decrease) in which the
control output value changes according to the polarity of the deviation between the SP
and the PV. In reverse action (factory default setting), the control output value
decreases when the PV is greater than the SP and vice versa. The control output is
varied using direct control or reverse control specified beforehand in sync with the
deviation between the SP and the PV at that point. Direct action and reverse action can
be switched in the middle of operation.
Condition
ON/OFF output
Current output
PV time-proportional
output
Output change direction
for the 4-20 mA case
PV>SP
OFF
Current decrease
ON time decrease
Reverse action Direct action
SP
Minimum value
(PV is low)
Maximum value
(PV is high)
4mA PV
20 mA
PV
ON
Current increase
ON time increase
PV>SP
ON
Current increase
ON time increase
PV
OFF
Current decrease
ON time decrease
Output
value
(Increase)
(Decrease)
↑
↓
SP
4mA
20 mA PV
Output
value
(Increase)
(Decrease)
↑
↓
Minimum value
(PV is low)
Maximum value
(PV is high)
1.7 PID Parameter Settings