Introduction

This manual describes the Woodward 723PLUS Digital Marine Speed Controls, 8280-422 (low-speed engines, typically less than 100 rpm) and 8280-423 (medium-/high-speed engines, over 100 rpm). These controls are intended to be used where mechanical load sharing and unit clutching is required.

Application

These controls are designed to regulate the speed and load of diesel engines in dual-engine marine applications that require mechanical load sharing. The applications include mechanically combined two-engine operation for main propulsion and dredge operation, including those with flexible couplings (see Figure 1-1).

Features include:

Clutch control and permissive logic

Soft loading and unloading

Mechanical load sharing by matching fuel rack positions

Advanced speed-sensing algorithms

Firing torsional filtering

Flexible coupling torsional filtering

Torque fuel limiting

Start fuel limiting

Manifold or external fuel limiting

Rack position sensor failure mode retains load sharing

Single-throttle operation for both engines during clutched operation

Inputs include:

Two magnetic pickups (MPUs) or proximity switches for sensing engine

speed, capable of filtering torsionals or providing redundant speed signals

4–20 mA remote speed-setting input

4–20 mA rack position feedback input

4–20 mA manifold or external fuel input

±5 Vdc auxiliary input

Eight discrete inputs (contact inputs) for: Run/Stop, Clutch Request, Clutch Status, Idle/Rated, Raise Speed, Lower Speed, configurable contact for either Overspeed Test or Emergency Declutch, and configurable contact for either Alarm Reset or Dynamics 2.

Load sharing lines for the mechanical load sharing

Redundant communication ports J2 and J3 used for control status needed between controls for proper clutching and loading.

Outputs include:

Three 4–20 mA outputs which are configurable for: engine speed, engine load, speed reference, actuator driver output, remote speed input, and PID output .

0–200 mA actuator output compatible with most Woodward actuators

One relay output for clutch permissive/close contact out

Two Alarm relay outputs: each is user-configurable for normally open/ closed contact output. There are 13 status choices to choose among for these two alarms.

Serial port for a hand-held programmer to monitor and program the 723PLUS control

The 723PLUS control provides several functions including speed governing, mechanical load sharing, clutching/declutching control logic including speed matching during clutching, and soft engine loading/unloading. Each engine requires a 723PLUS control along with the associated I/O connections, transducers, and accessories (see Figure 1-4). The 723PLUS controls use a master/slave relationship during clutching and load sharing operations. The master unit is the first unit to close its clutch. The slave unit is the last unit to close its clutch. The 723PLUS control’s primary job is speed control. When the engines are clutched together, the 723PLUS control’s job also becomes one of a load sharing control using the master’s speed reference. The engine clutching process starts by matching (synchronizing) the engine speeds and then giving a clutch permissive command. Once clutched, the engine is soft-loaded until the loads are balanced mechanically (equal fuel-rack positions). The engines will maintain equal loads (load sharing) during clutched operation. During a declutching operation, the declutching engine is soft-unloaded and, when the unit is at the unload trip level, a declutch command is given. This is a simplified description, and several other items affect the 723PLUS control’s operation. See Chapter 3, Function Operation, for more details.

The 723PLUS control consists of a single printed circuit board in a sheet metal chassis. Connections are via three terminal strips and three 9-pin subminiature D connectors. The 723PLUS control should be located in a protected location. See Woodward manual 02877, 723PLUS Digital Control Hardware, for installation details.

723PLUS Control Accessories

A hand-held programmer, part number 9907-205, is used to adjust and monitor the 723PLUS control. The programmer plugs into the serial port J1 (9-pin D connector).

Woodward has several LVDT signal conditioners that we can recommend for fuel rack position transducer signal conditioning.

8272-824 (4–20 mA output, 24 Vdc input) 

8272-834 (0–10 Vdc output, 24 Vdc input)

Woodward 8280-416 723 Plus Digitale Controllo 9906-619

Woodward 8280-416 723 Plus digital controller 9906-619

Woodward 8280-416 723 Plus Contrle Numrique 9906-619

Woodward 8280-416 723 control number 9906-619