Woodward 9907-164 505E Digital Governor

The 505E is a 32-bit microprocessor based controller designed to control single extraction, extraction/intake, or intake steam turbines. The 505E is field programmable, allowing a single design to be used for many different control applications and reducing cost and lead time. It uses menu driven software to guide the field engineer in programming the controller to a specific generator or mechanical drive application. The 505E can be configured to operate as a standalone unit or it can be used in conjunction with a plant's distributed control system.

The 505E is a field configurable steam turbine control and operator control panel (OCP) in one package. The 505E has a comprehensive operator control panel on the front panel that includes a two-line (24-character per line) display and a set of 30 keys. This OCP is used to configure the 505E, make online program adjustments, and operate the turbine/system. The OCP's two-line display provides easy-to-understand instructions in English, and the operator can view actual and setpoint values ​​from the same screen.

The 505E interfaces with two control valves (HP and LP) to control two parameters and limit one additional parameter if required. The two controlled parameters are typically speed (or load) and suction/inlet pressure (or flow), however, the 505E can be used to control or limit: turbine inlet pressure or flow, exhaust (back pressure) pressure or flow, first stage pressure, generator power output, plant inlet and/or outlet levels, compressor inlet or exhaust pressure or flow, unit/plant frequency, process temperature, or any other turbine related process parameter.

The 505E can communicate directly with a plant distributed control system and/or CRT-based operator control panel via two Modbus communications ports. These ports support RS-232, RS-422, or RS-485 communications using either ASCII or RTU MODBUS transmission protocols. Communications between the 505E and the plant DCS can also be performed via a hardwire connection. Because all 505E PID setpoints can be controlled via analog input signals, interface resolution and control are not sacrificed.

The 505E also offers the following features: First-out trip indication (5 total trip inputs), critical speed avoidance (2 speed bands), automatic start sequence (hot and cold start), dual speed/load dynamics, zero speed detection, peak speed indication for overspeed trip, and synchronous load sharing between units.

Using the 505E

The 505E controller has two normal operating modes: Program Mode and Run Mode. Program Mode is used to select the options needed to configure the controller to suit your specific turbine application. Once the controller has been configured, Program Mode is not typically used again unless turbine options or operations change. Once configured, Run Mode is used to operate the turbine from startup to shutdown. In addition to Program and Run Modes, there is a Service Mode that can be used to enhance system operation while the unit is in operation.