7. Compressor module (VSD)
36
"Operation" digital input
A signal must be connected to this input to indicate that
the compressor is ready to produce compressed air
after sending a remote load signal.
On compressor controls which do not provide such a
signal the input can be connected to the collective fault
signal of the compressor.
This will indicate to the GD Connect 12 that there is no
fault at the compressor.
A parameter on the GD Connect 12 can be used to
define whether or not a voltage at the input signals
availability.
"Warning" digital input
A warning message can optionally be connected at this
input.
If no warning message is required or available, this
input can be left open.
A warning message has no influence on the regulation
of the compressor. A warning message that is received
is simply displayed on screen and is stored in the event
list for the compressor.
"Load" digital input
The contact regulation valve coil can be connected
directly to this input.
If the compressor control energizes the coil of the
regulation valve, the compressor module detects the
voltage over the coil and indicates to the GD Connect
12 that the compressor is on load.
Any output which indicates that the compressor is on
load could also be used.
A parameter on the GD Connect 12 can be used to
define whether or not a voltage at the input signals the
compressor load.
Digital outputs
The use of digital outputs is optional.
The status of these outputs is indicated via three LEDs.
These digital outputs are change-over contacts and can
be adapted to the requirements of the compressor
control by selecting the appropriate terminals.
Wiring diagrams with examples showing how to connect
a compressor control with line pressure sensor or line
pressure switch can be found in the annex.
Digital output DO-1
Do not use this input to switch the compressor on and
off.
This output can be used for a "remote load enable"
signal if required.
Digital output DO-2
Do not use this input to switch the compressor on and
off.
This output can be used for a "remote load" signal if
required.
Analog inputs
Analog input AI-1
This analog input detects the line pressure at the
compressor.
This is done by removing the compressor's line
pressure sensor from the compressor control and
connecting it to analog input AI-1 on the compressor
module.
This is necessary for the following reasons:
The line pressure at the compressor can be
monitored and if it is getting too high, the
compressor can be set to off-load.
If the GD Connect 12 or the compressor module
fails, an internal relay will short circuit the analog
input and the analog output. This will cause an
automatic connection of the line pressure sensor to
the compressor control to allow the compressor to
continue to operate.
The relay short circuits terminals 25 and 28.
