Mitsubishi Electric MELSEC iQ-R Series User Manual page 96

Operation to be executed when an alert occurs or does not occur
When a loop disconnection detection alert is issued, 'CH1 Alert flag' (XC) and CH1 Loop disconnection detection (Un\G401,
b13) turn ON, and CH Loop disconnection detection (alarm code: 089H) is stored in 'Latest alarm code' (Un\G3). (
Page 151 List of Alarm Codes)
When a loop disconnection detection alert is not issued and the auto tuning is completed successfully, "Loop disconnection
detection judgment time" of "Loop disconnection detection setting" in "Application Setting" is automatically updated to the
value calculated by the auto tuning.
When a loop disconnection alert occurs, there may be an error in the control loop. Thus, even though the auto
tuning has been completed successfully, check the control loop and if the loop disconnection detection
judgment time of the auto tuning is appropriate.
Clearing the alert status
When one of the following conditions is satisfied, 'CH1 Alert flag' (XC) and CH1 Loop disconnection detection (Un\G401, b13)
turn OFF.
• 'CH1 PID control forced stop command' (YC) is turned from OFF to ON.
• 'Setting/operation mode command' (Y1) is turned from ON to OFF and the mode shifts to the setting mode.
• A manipulated value (MV) becomes greater than the lower limit output limiter value and smaller than the upper limit output
limiter value.
• The value 0 is set for "Loop disconnection detection judgment time" of "Loop disconnection detection setting" in
"Application Setting."
• MAN (1) has been set for 'CH1 AUTO/MAN mode shift' (Un\G518).
• "Disable" has been set for "During AT loop disconnection detection function is enabled/disabled" of "Auto tuning setting" in
"Application Setting."
After executing the operations above, turn from OFF and ON 'Error reset command' (Y2) to clear the value in 'Latest alarm
code' (Un\G3).
1 FUNCTIONS
94
1.30 During AT Loop Disconnection Detection Function