Page 15 of 18
Note: The Filter is available only for the process value (PV), and is performed for the displayed value only.
The controller is designed to use an unfiltered signal for control even when a filter is applied. If a lagged
(filtered) signal is used for control; it may produce an unstable process.
2-4.Filter Characteristics
2.7
Failure Transfer
The controller will enter failure mode if one of the following conditions occurs:
1.
An SBER error occurs due to an input sensor break, an input current below 1mA for 4-20mA, or an
input voltage below 0.25V for 1-5 V.
2.
An ADER error occurs due to the A-D converter failing.
Output 1 and Output 2 will perform the failure transfer (O1.ft & O2.ft) function as the controller enters failure mode.
2.7.1
Output 1 Failure Transfer
If Output 1 Failure Transfer is activated, it will perform as follows:
1.
If output 1 is configured as proportional control (PB≠0), and BPLS is selected for O1FT, then output
1 will perform a Bumpless transfer. After that, the previous average value of of the output will be
used for controlling output 1.
2.
If output 1 is configured as proportional control (PB≠0), and a value of 0 to 100.0 % is set for O1FT,
then output 1 will perform failure transfer. After that the value of O1FT will be used for controlling
output 1.
3.
If output 1 is configured as ON-OFF control (PB=0), then output 1 will transfer to an off state if OFF
is set for O1FT, or it will transfer to an on state if ON is set for O1FT.
2.8
Auto-Tuning
The Auto-Tuning process will be performed at the set point (SP1). The process will oscillate around the
set point during the tuning process. Set a set point to a lower value if overshooting beyond the normal
process value will cause damage. It is usually best to perform Auto-Tuning at the Set point the machine is
expected to be operated at, with the process running normally (i.e. material in the oven, etc.)
Auto-Tuning is generally applied in the following cases:
v
Initial setup for a new process
v
The set point is changed substantially from the previous Set point when Auto-Tuning was performed.
v
The control result is unsatisfactory
