Shinko BCD2R - Control Action Behavior Details; Low Limit Control Action Explanation; Auto vs. Manual Limit Control Modes

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7.2 Low limit control action (Fig. 7.2-1)
Auto limit control will be used for purposes of explanation of the Low limit control action. (Refer to Section 7.3)
(Fig. 7.2-1)
(1) Limit control action will initiate after power supply to the controller is turned on.
(2) If PV drops below SV, the EXCEEDED and RESET indicators light, and OUT1 (Limit control output
terminals 15 and 16) is turned OFF.
(3) If PV exceeds [SV+OUT1 hysteresis], the EXCEEDED indicator goes off. At this time, the RESET
indicator is lit, and OUT1 (Limit control output terminals 15 and 16) is in OFF status.
(4) If the key is pressed, or if external reset input terminals 9 and 12 are shorted, the RESET
indicator goes off, OUT1 (Limit control output terminals 15 and 16) is turned ON, and limit control
action initiates again.
(5) While the EXCEEDED indicator is lit, even if the key is pressed or even if external reset input
terminals 9 and 12 are shorted, limit control action does not initiate.
7.3 Auto/Manual limit control
Auto limit control
When the power supply is turned on, or after the power is restored, the AUTO indicator lights, and
limit control starts automatically even if the key is not pressed, or even if external reset
input is not shorted.
For High limit control, when PV exceeds SV–Hysteresis, the limit control action does not initiate.
For Low limit control, when PV drops below SV+Hysteresis, the limit control action does not initiate.
Limit control action does not initiate while the EXCEEDED indicator is lit.
Manual limit control
In the following cases, the RESET indicator lights, and it is necessary to reset the unit manually.
(Press the key, or short the external reset input terminals.)
• When power is turned on
• When power is restored
• For High limit control, when PV drops below the SV–Hysteresis after PV exceeded SV.
For Low limit control, when PV exceeds the SV+Hysteresis after PV dropped below SV.
However, the limit control action does not initiate as follows (Same as Auto limit control).
For High limit control, when PV exceeds SV–Hysteresis, the limit control action does not initiate.
For Low limit control, when PV drops below SV+Hysteresis, the limit control action does not initiate.
Limit control action does not initiate while the EXCEEDED indicator is lit.
The key or External
reset input
De-energized action