8.7 Performing Program Control
In Program control, SV changes as time elapses, and PV is controlled in order to reach each SV.
SV and time can be set for every step, and a maximum of 9 steps can be repeatedly controlled.
SV can be set as (Fig. 8.7-1).
(e.g.) Program control of electric furnaces in ceramic manufacture, food machinery, etc.
(Fig. 8.7-1)
Major functions of Program control
are shown below.
Number of patterns and steps
: 1 pattern; 9 steps
[Wait function]
While Program control is running, the program does not proceed to the next step
until the deviation between PV and SV enters SV
Wait value at the end of step.
The PV Display flashes while the Wait function is working.
The Wait function is cancelled on the condition that:
• When program pattern is rising: PV is higher than SV- Wait value
• When program pattern is falling: PV is lower than SV+ Wait value
Step
1
2
3
4
5
: PV
: Program pattern
: Program pattern delayed by T due to the Wait function
(Fig. 8.7-2)
200
0
T
T
If PV becomes higher than 190 , the wait
function will be cancelled, proceeding to Step 2.
Wait value 10
As PV is not in the range of SV Wait value, the unit
is in Wait status, and does not proceed to Step 2.
The STEP indicator flashes during Wait action (T time).
Temperature
Time
Step
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