Publication 1747-RM001G-EN-P - November 2008
Proportional Integral Derivative Instruction 9-9
The deadband extends above and below the setpoint by the value entered. The
deadband is entered at the zero crossing of the process variable and the
setpoint. This means that the deadband is in effect only after the process
variable enters the deadband and passes through the setpoint.
The valid range is 0 to the scaled maximum, or 0 to 16,383 when no scaling
exists.
Scaled Error
Scaled error is the difference between the process variable and the setpoint.
The format of the difference (E = SP-PV or E = PV-SP) is determined by the
control mode (CM) bit. See Control (CM) on page 9-10.
Auto / Manual (AM)
The auto/manual bit can be set or cleared by instructions in your ladder
program. When off (0), it specifies automatic operation. When on (1), it
specifies manual operation. In automatic operation, the instruction controls
the control variable (CV). In manual operation, the user/control program
controls the CV. During tuning, set this bit to manual.
Table 9.9 Scaled Error Parameter
Tuning
Parameter
Descriptions
Address Data
Format
Range Type User
Program
Access
Scaled Error Word 15 word
(INT)
-32,768 to +32,767 status read only
Table 9.10 Automatic/Manual Parameter
Tuning Parameter
Descriptions
Address Data Format Range Type User
Program
Access
AM - Automatic/Manual Word 0, Bit 1 binary (bit) 0 or 1 control read/write
TIP
Output limiting is also applied when in manual.
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