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CHAPTER 4 FUNCTIONS
4
4.23 During AT Loop Disconnection Detection Function
4.23 During AT Loop Disconnection Detection Function
This function detects loop disconnections during auto tuning (AT). With this function, a channel that is not controlled
can be detected during auto tuning, thus the error channel is detected more than two hours before the auto tuning error
occurs. The auto tuning continues even if an alert is output for the loop disconnection detection. For details on the loop
disconnection detection function, refer to the following.
Page 253, Section 4.22
● This function is enabled even when the peak current suppression function or the simultaneous temperature rise function
is used.
● The loop disconnection detection dead band setting is disabled in loop disconnection detection during AT (The dead
band is not set.)
(1) Conditions to start the during AT loop disconnection detection function
• Enable (1) is set to During AT loop disconnection detection function enable/disable setting (Un\G571).
• A value other than 0 is set to CH Loop disconnection detection judgment time (Un\G59, Un\G91, Un\G123,
Un\G155).
• The standard control is set for the control mode. (The function can be used for CH3 or CH4 where the mix
control is set.)
The during AT loop disconnection detection function does not operate if the above conditions are not met. An
error or alarm does not occur even though the conditions are not met.
(2) Setting method
Set the function as shown below.
1. Set CH Loop disconnection detection judgment time (Un\G59, Un\G91, Un\G123, Un\G155)
*1
( Page 124, Section 3.4.2 (33))
*1 It takes time before the temperature starts rising due to the dead time of the controlled object. Consider the dead time of
each object and set the value.
2. Set Enable (1) to the bit of During AT loop disconnection detection function enable/disable setting
(Un\G571) for the channel where the loop disconnection detection is to be performed. ( Page
145, Section 3.4.2 (66))
3. Turn on from off CH Auto tuning instruction (Yn4 to Yn7).
Remark
● Setting example for the control to rise the temperature by 200°C for 40 minutes
It takes approx. 24 seconds to rise the temperature by 2°C. Also, the dead time of the controlled object must be added as
the time required before the temperature starts rising. Therefore, when assuming the dead time of the controlled object is
6 seconds, set 30 (24 seconds + dead time of the controlled object) to CH Loop disconnection detection judgment time
(Un\G59, Un\G91, Un\G123, Un\G155).