20: PID I
NSTRUCTION
O
PEN
N
ET
C
ONTROLLER
U
SER
’
S
M
ANUAL
20-13
Destination Operand D1 (Manipulated Variable)
The data register designated by destination operand D1 stores the manipulated variable of –32768 through 32767 calcu-
lated by the PID action. When the calculation result is less than –32768, D1 stores –32768. When the calculation result is
greater than 32767, D1 stores 32767. While the calculation result is less than –32768 or greater than 32767, the PID action
still continues.
When the output manipulated variable limit is disabled (S2+2 set to off) while the PID action is in progress, the data regis-
ter designated by S1+1 holds 0 through 100 of the manipulated variable (D1), omitting values less than 0 and greater than
100. The percent value in S1+1 determines the ON duration of the control output (S2+6) in proportion to the control
period (S1+13).
When the output manipulated variable limit is enabled (S2+2 set to on), the manipulated variable (D1) is stored to the out-
put manipulated variable (S1+1) according to the output manipulated variable upper limit (S1+16) and the output manipu-
lated variable lower limit (S1+17) as summarized in the table below.
While manual mode is enabled with the auto/manual mode control relay (S2+1) set to on, S1+1 stores 0 through 100 of the
manual mode output manipulated variable (S1+18), and D1 stores an indefinite value.
While auto tuning is in progress, S1+1 stores 0 through 100 of the AT output manipulated variable (S1+22), and D1 stores
an indefinite value.
Examples of Output Manipulated Variable Values
Output Manipulated
Variable Limit Enable
(S2+2)
Output Manipulated
Variable Upper Limit
(S1+16)
Output Manipulated
Variable Lower Limit
(S1+17)
Manipulated Variable
(D1)
Output Manipulated
Variable
(S1+1)
OFF (disabled)
—
—
≥
100
100
1 to 99
1 to 99
≤
0
0
ON (enabled)
50
25
≥
50
50
26 to 49
26 to 49
≤
25
25
10050
—
≥
100
50
1 to 99
(1 to 99)
×
0.5
≤
0
0
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