Honeywell UDC 3300 manual Alg, Pidloops, 3PSTEP Loop 2LOOPS Cascad

Lower Display

Prompt

CONT ALG (continued)

PIDLOOPS*

*Only available on Expanded Model DC330E Dual loop.

CONT2ALG

Upper Display

Range of Setting

or Selection

3PSTEP

1LOOP 2LOOPS*

CASCAD*

Parameter

Definition

THREE POSITION STEP— The Three Position Step Control algorithm allows the control of a valve (or other actuator) with an electric motor driven by two controller relay outputs; one to move the motor upscale, the other downscale without a feedback slidewire linked to the motor shaft. The deadband is adjustable in the same manner as the duplex output algorithm.

The Three Position Step Control algorithm provides an output display (OUT) which is an estimated motor position, since the motor is not using any slidewire feedback. Although this output indication is only an approximation, it is “corrected” each time the controller drives the motor to one of its stops (0 % or 100 %). It avoids all the control problems associated with the feedback slidewire (wear, dirt, noise). When operating in this algorithm, the estimated OUT display is shown to the nearest percent (i.e., no decimal).

Refer to the Operation section for motor position displays.

As a customer configurable option, when a second input board is installed, the motor slidewire can be connected to the controller. The actual slidewire position is then shown on the lower display as POS. This value is used for display only. It is NOT used in the Three Position Step algorithm. To configure this option, set Input 2 actuation to SLIDEW. Calibrate the slidewire.

Other prompts affected: DEADBAND

PID LOOPS— This is the PID loop selection.

1 LOOP— Select to use one loop of control.

2 LOOPS— Select to use two PID loops of control, each with two sets of tuning parameters and a set of control parameters.

CASCADE— Select for Cascade Control. In a cascade control system the output of one PID loop is used to adjust the setpoint of the second control loop and the second loop’s output actually adjusts the final control element.

ATTENTION To enable a cascade loop, hold in the SETPOINT SELECT key until the RSP Annunciator

lights and an “I” appears as the upper display’s leftmost character to indicate Cascade mode. Pressing the key again disables the Cascade Loop and the annunciators turn off.

The CONTROL 2 ALGORITHM lets you select the type of control for Loop 2 that is best for your process. Only available if the controller is configured for Cascade or 2-Loop control.

3Pstep and On/Off are not available for the second control loop.

94 UDC 3300 Process Controller Product Manual 4/00