Specifications

8 – Configuring Points
130 R400
Analog Mode (MD)
The mode (or “MD”) is used to determine whether or not an operator is
permitted to control the output value. The two most common modes are:
“manual” and “automatic.” For more details about control modes, see “Control
Modes” on page 153.
Analog Setpoint (SP)
The setpoint (or “SP”) can be used to read and write an analog value in a
controller. Set points are represented in engineering units and are often used to
represent the ideal operating value for a process (for example, the temperature of
a furnace) or the setpoint of a control loop.
Analog Auxiliary Values (A1, A2, A3, and A4)
Up to four additional values can be used to read and write four analog values in
a controller. These auxiliary values are given names A1 to A4 and are represented
in engineering units. Auxiliary values are often used to represent the tuning
constants of a control loop.
Accumulator Point Parameters
Accumulator points represent totalizers. Figure 8.8, “Accumulator Point” on
page 131 shows the relationship between a field value and an accumulator point.
Figure 8.7 Analog Point
Controller ServerField
500.0
550.0
25.0
SP 500.0
PV 550.0
OP 25.0
SP
PV
OP
plscpcg.book Page 130 Monday, May 28, 2001 10:11 AM