Honeywell UDC 3300 Operating Modes, Available modes Mode definitions, Operating Mode Definitions

5.6 Operating Modes

Available modes

Mode definitions

The controller can operate in any of three basic modes:

•Manual—One or Two Loops

•Automatic with Local Setpoint—One or Two Loops

•Automatic with Remote Setpoint—One or Two Loops

•Manual Cascade

•Automatic Cascade

The manual and automatic control modes with Local and Remote setpoint are standard with the instrument; cascade control is optional.

Table 5-7 lists the available modes and their definitions.

Table 5-7 Operating Mode Definitions

Operating Mode

MANUAL

Definition

In the manual mode, the operator directly controls the controller output level. The process variable and the percent output are displayed. The configured High and Low Output Limits are disregarded and the operator can change the output value using the increment and decrement keys to the limits allowed by the output type (0 % to 100 % for a time proportioning output or –5 % to 105 % for a current output).

AUTOMATIC with LOCAL SETPOINT

AUTOMATIC with

REMOTE SETPOINT

MANUAL CASCADE

AUTOMATIC CASCADE

In automatic local mode, the controller operates from the local setpoints and automatically adjusts the output to maintain the setpoint at the desired value.

In this mode you can adjust the setpoint.

See Section 5.7 - Setpoints.

In automatic remote mode, the controller operates from the setpoint measured at the Remote setpoint input. Adjustments are available to ratio this input and add a constant bias before it is applied to the control equation.

See Section 3 - Configuration, Control Set up group.

In the manual cascade mode, both control loops are in manual although there is still only one output active. This mode is used to bring both loops into a reasonable operation area, at which point the unit is placed into the automatic cascade mode.

If Loop 1 is placed in Manual control mode, then Loop 2, if in auto, is then placed in a pseudo-manual mode thereby eliminating output bumps when Loop 1 is returned to Automatic control mode.

In Automatic cascade mode, there are two control loops, with one loop’s output acting as the setpoint for the second control loop. There is only one physical output in this mode.

156 UDC 3300 Controller Product Manual 4/00