Woodward 2301D, Инструкция по установке и эксплуатации, Страница: 29 / 130

Manual 26247 2301D/2301D-EC Digital Control
Woodward 21
Analog Output #1 (Terminals 16-17)
The analog output can be configured several different ways depending on the
application needs. The output current is for either 0 to 20 mA or 4 to 20 mA. This
current signal is supplied to terminals 16(+) and 17(–). Note that the these
terminals must be isolated from ground. The Output can be software configured
to one of several control parameters. These parameters include:

Engine Speed

Engine Speed Reference

Fuel Demand

Generator Output

System Load Percent

Synchronizer Input

Analog Input #2

Speed Setting Bias Signal

Base Load Reference
The Analog Output is factory set for 4 to 20 mA, representing the engine speed.
Default range is 0 to 100%. Software settings must be changed if an output of 0
to 20 mA is needed. Use shielded twisted-pair wires. For electrically isolated
devices such as 4 to 20 mA analog meters, the shield should be grounded at the
control end of the cable. For input to other devices, use the recommendation of
the device manufacturer.
Communication Port
The control’s serial communications port is used to configure and service the
unit, as well as communicate to a Human Machine Interface (HMI) or plant
distributed control system (DCS). This port’s protocol is switchable via the
control’s “Modbus communications enable” contact input. When this contact input
is open or has no connection to it, the control’s communications port
communicates using an RS-232 driver and a Servlink/DDE protocol. The
Servlink/DDE protocol is used to communicate with Woodward’s Watch Window
program for unit configuration and or service. Refer to Chapter 3 for configuration
and setup instructions.
When the control’s “Modbus Communications Enable” contact input is closed, the
control’s communications port then communicates using a Modbus RTU protocol,
functioning as a Modbus Slave device, via RS-232 or RS-422 drivers, depending
on the configuration. The 2301D-EC can be fully operated and all control values
monitored via Modbus communications. Alternatively Modbus communications
can be used to interface with a PLC or plant DCS. Refer to Figure 2-3 for plant
wiring information.
The communication port must be connected with an approved
jacketed serial communication cable. The connector must be
secured to the 2301D-EC to prevent contact with other circuits.