Table of Contents
Advertisement
PRESYS
|
Instruments
Hyst - This is the parameter determining when the output should be changed.
Whenever the control variable crosses the upper and lower hysteresis limits, the
Controller output should cause the D.Out value to vary for the more or for less from
its original value.
LIM.S, LIM.I - They correspond to the upper and lower safety limits (trip point),
which determine a span within which the control variable can vary due to the auto-
tune process. In case the control variable exceeds this span the auto-tune process is
aborted.
Fig. 25 - Process variable and control output for on demand auto-tune
The on demand auto-tune activation involves the followign steps:
i) start by entering the Configuration level 6.
ii) to select the channel in which the auto-tune will be carried out (CH-1) or (CH-2).
iii) to select the amplitude of the square wave (D.OUT) and of the hysteresis (Hist),
see figure 25.
iv) to select the ON option for the AUTO parameter (auto-tune on demand) and press
ENTER.
Note that as soon as the third step is completed the Controllers will go to
normal operation mode with the TUNE message and the controlled variable
alternating on the upper display. Upon completion of the auto-tune cycle the
instrument no longer displays the TUNE message (see figure 26).
DCY - 2057 Pressure Controller
Maintenance
Page 43
Advertisement
Table of Contents
