30 November 1998
Standard features will allow the replacement of any controller by a spare not necessarily of the same
(3) The single-loop digital controller will have the following inputs and outputs:
(a) A process variable analog input (PV).
(b) A remote setpoint analog input for control point adjustment (CPA).
(c) An analog output (OUT).
(d) A process variable actuated contact closure output (PV contact).
(e) A contact output that responds to the difference between PV and CPA analog inputs (DEV
(f) An analog output which is identical to the process variable input (PV Retransmission).
(4) Some controller features are configurable by manual input, and others are selectable by
setting switches or jumper wires. The configuration methods vary with the specific manufacturer and
model. The controller will have the selection of features for its inputs and outputs as shown in table 2-1.
Adjustable bias of setpoint relative to the PV input range.
Adjustable ratio of setpoint relative to the PV input range.
Scalable to the range of the CPA input signal.
High and low limits of setpoint adjustment.
Selection of direct acting or reverse acting.
Adjustable high and low limits.
Adjustable bias (Manual reset).
Selection of manual or automatic control.
Selection of proportional (P), proportional plus integral (PI), and
proportional plus integral plus derivative control modes (PID).
Selection of manual tuning or operator initiated self tuning.
Manual reset feature for use when the controller is configured
from porportional mode only and is manually tuned.
Adjustable contact setpoint.