Woodward 2301D, Инструкция по установке и эксплуатации, Страница: 21 / 130

Manual 26247 2301D/2301D-EC Digital Control
Woodward 13
Discrete Inputs (Terminals 28–38)
Discrete inputs are the switch input commands to the 2301D control. They
interact in such a way as to allow engine control and power management under a
variety of conditions. Positive Voltage is supplied to the discrete input terminal
when an input switch or relay contact closes. This will cause the input state for
that discrete input to be “TRUE” (displayed as “CLOSED”). The input terminal will
be open circuited when the input switch or relay contact opens. This will cause
the input state for that discrete input to be “FALSE” (displayed as “OPEN”). When
the input switch or relay contact is closed, the voltage supplying the discrete
inputs should be present from the appropriate discrete input (terminal 31, 32, 33,
34, 35, 36, 37, or 38) to terminal 30 (common). Terminal 30 is the common return
path for all of the discrete input channels. A lower voltage indicates that the
switch contacts have too high a resistance when closed and should be replaced.
These terminals must be isolated from ground.
In systems that provide an external low voltage source to power the 2301D
control, the discrete inputs may be powered by this external low voltage. The
voltage source used must be capable of supplying 100 mA at a voltage level of
18 to 40 Vdc. Connect the external low voltage source negative to terminal 30(–).
Connect the external low voltage source positive to the appropriate input switch
or relay contact and connect the mated switch or relay contact to the
corresponding discrete input terminal on the 2301D control.
In systems where the external low voltage dc power is not appropriate, the
discrete inputs may be powered by the internal 24 Vdc Discrete Input Power
source at terminal 28 and 29. This source is capable of supplying 100 mA at a
voltage level of 24 Vdc. Connect the internal 24 Vdc voltage source positive from
terminal 28 to the appropriate input switch or relay contact, and connect the
mated switch or relay contact to the corresponding discrete input terminal on the
2301D control. Assure that a connection exists between terminal 29 and terminal
30 when using the internal Discrete Input Power. Do not power other devices
with the internal discrete input power source, and assure that the switch or relay
contacts used are isolated from any other circuit or system.
Discrete inputs with cable lengths greater than 30 meters that are
used for critical functions, such as emergency stop, should not be
floated in either an on or off state. These inputs should be switched
to +24 Vdc or ground.
Close to Run or Minimum Fuel (Terminal 31)
The external contact used to activate the Close to Run command connects to
terminal 31. This discrete input changes the control operation by immediately
decreasing the fuel demand to zero. When the switch or relay contacts are
closed, the control is allowed to control the fuel in an attempt to control the
speed/load of the prime mover. When the switch or relay contacts are open, the
Minimum Fuel Function will immediately pull the fuel demand to zero.
Do NOT use the minimum fuel contact as part of any emergency stop
sequence.