D396-14-880 Issue J
Page 8
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Introduction
1.7.2
Electrical supplies
Two 24 V supplies are provided, as described below
Vent-valve supply
This electrical supply is provided to operate a vent-valve fitted to your EXT pump or vacuum system. The Controller
automatically opens the valve when the speed of the pump falls to below 50% of full rotational speed (see
). You can also configure the Controller to operate the valve in other specific conditions: refer to Sections
and
Air-cooler supply
This electrical supply is provided to operate an ACX air-cooler fitted to your EXT pump. The electrical supply is on
whenever the Controller is on. If your pump is water-cooled, you can use this supply to operate a solenoid-valve to
control the flow of water through the water-cooler.
1.7.3
Control inputs
Note:
The Controller is supplied with wire links fitted to close the TMP and SYS Interlocks and to close the Start/
Stop input. The Controller cannot start the EXT pump if any of these three inputs are open.
You can use these signals to control the operation of the EXT pump. The signals are switch-type inputs in which two
pins on the logic interface are linked (closed) when you want to set the required signal and are unconnected (open)
when you do not wish to set the signal.
Two of the inputs (Start/Stop and Standby) have the same functions as the buttons of the same name on the
Controller front panel (on EXC120, EXC300 and EXC300M Controllers). The other two inputs are Interlocks and the
Controller will only operate the EXT pump if both Interlocks are closed (and if no Fail condition is present).
Start/Stop
Use the Start/Stop input to Start and Stop the EXT pump. Note that on the EXC120, EXC300 and EXC300M Controllers,
the signal is wired in series with the Start/Stop button on the front panel, so you must close the Start/Stop input and
press the Start/Stop button on the front panel to Start the pump. To stop the pump, either open the input (that is,
open the link between the appropriate logic interface pins), or press the Start/Stop button again.
Standby
Close the Standby input to select pump Standby (refer to
). Note that on the EXC120, EXC300 and EXC300M
Controllers, the Standby input is wired in parallel with the Standby button on the front panel and you can use either
the button or the input to select Standby at any time.
TMP Interlock (TMPI)
Use the TMP Interlock to delay the start of the EXT pump until the backing pump has sufficiently reduced the pressure
in the vacuum system. You can therefore control the TMP Interlock either by a timer or by a pressure switch in the
backing pipeline of your system. Note that:
z
If the TMP Interlock is open when Start is selected, the Start LED on the Start/Stop button will flash.
z
If the TMP Interlock is opened after Start is selected, but with the SYS Interlock open, the Start LED will
continue to flash.
z
If the TMP Interlock is opened after the EXT pump has started, the Controller will trip into Fail condition.
