Honeywell UDC 3300 manual Two Loops of Control Overview, Introduction Selections

5.12 Two Loops of Control Overview

Introduction

Selections

The UDC 3300 can operate using two independent loops of control or internal Cascade control.

Available only on Expanded Model DC330E-XX-XXX.

TWO INDEPENDENT LOOPS—See Functional Overview Block Diagrams for Loop 1 and Loop 2 (Figure 5-2) and Table 5-21 for selections based on these diagrams.

The following rules apply for two independent loops:

•Current output on Loop 2 requires auxiliary output.

•Loop 2 Current Duplex output is limited to 2nd Current output signal only.

•Loop 2 relay output is always dedicated to relay output 2.

•No Time Duplex outputs on Loop 2.

•No ON/OFF or 3 Position Step algorithms on Loop 2.

•No Position Proportional output is available on 2-loop controllers.

INTERNAL CASCADE CONTROL—See Functional Overview Block Diagram (Figure 5-3) and Table 5-25 for selections based on these diagrams.

The following rules apply for internal Cascade control:

•Loop 2 must be the primary loop.

•Loop 1 must be the secondary (internal or slave) loop because all output forms exist on Loop 1.

•Loop 1 remote setpoint is fixed as Loop 2 output.

•No Position Proportional output is available on cascade controllers.

Refer to Figures 5-2, 5-3, and 5-4 Block Diagrams and Table 5-21 for selections based on these diagrams.

Table 5-21 Control Loop Selections

Loop Input 1 Input 2

Input Algorithm

LOOP 1

LOOP 2

Process Variable*

Remote Setpoint

Feedforward

Process Variable*

Remote Setpoint

Via Configuration or

Digital Inputs

No

No

Via Configuration or

Digital Inputs

No

Via Configuration or

Digital Inputs

Via configuration or

Digital Inputs

Yes

Via Configuration or

Digital Inputs

Via Configuration or

Digital Inputs

Yes

Yes

Yes

Yes

Yes

Feedforward No Yes

*The PV may be a combination of multiple inputs via a Loop input algorithm.

Yes

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