EAF
Process Control Instructions
Chapter 16
16-33
Set Output will not override Output Limiting. The Control Output abides
by the Output Limiting value. For example, if Output Limiting is enabled
and the Minimum Output is 30% and the set output is set to 0% and
enabled, the Control Output goes to 30%.
Set Output Value (Word 11)
When operating in the Set Output mode, this value is sent as the Control
Output. The PID instruction uses the value in this word only when the Set
Output bit is set. The Set Output value should be entered as 0-100%
Control Output range.
Range
0000 – 0100 percent; positive integer value.
Sign Bit Word (Word 02)
This word contains the PID sign bits.
Set Point Error (Word 01, Bit 13)
This bit is set/reset by the EAF instruction when the Set Point (SP) has
been set out of the Maximum or Minimum Scaling Value ranges.
Reset (0)
SP is in range
Set (1)
SP is out of range
Set Point Sign (Word 02, Bit 05)
Set/Reset this bit to change the sign of the Setpoint.
Reset (0)
SP is positive
Set (1)
SP is negative
SP (Set Point) (Word 03)
This is the desired value of the process variable. Enter it with the same
engineering units as the Minimum Scaling Value and Maximum Scaling
Value. Use the same implied decimal point.
Status Word (Word 01)
This word contains the PID Status Bits.
Tieback
The Manual Control Station output is brought into the PID instruction as
tieback (TB). This allows a bumpless transfer from manual to
automatic control.
The tieback input (output tracking) from a manual control station must also
have the range of 0 to 4095. The instruction masks the upper four bits of
this 16 bit value.
Also, see Control Output Tracking.
