2. Installation
2.1. Mounting
The GX Tank 140 enclosure is mounted using the slotted flanges which protrude from either side of the base.
Use pan/truss head screws with washers to secure the unit, ensure that the screw thread outer diameter is a clearance fit within the flange slots (3.0mm max OD) and do not over tighten.
2.2. Electrical connections
All electrical connections are located on the front face of the GX Tank 140 unit and made using the pluggable terminal blocks supplied.
A clearly labelled wiring schematic diagram is also conveniently printed on the top face of the unit.
2.2.1. Power supply
The GX Tank 140 unit is self powered from USB interface and does not require an external power source.
Sensors can be powered through the unit in two different ways, depending on the channel used:
Channels 1 and 2: External Power Supply
The connector labeled “Ext. Power” can be used to distribute power from an external source to sensors connected on channels 1 and 2.
A self-resetting fuse (20mA) in this circuit prevents the unit from damage, even in case of a wiring short circuit or faulty sensor.
Channels 3 and 4: Internal 24VDC Power Supply
Channels 3 and 4 are powered by an internal supply (isolated from USB) with a voltage of 24VDC.
The outputs are equipped with a self-resetting fuse that limits the current to a maximum of 20mA per channel.
2.2.2. Voltage output sensors (0 to 10VDC)
Before connecting tank sensors that provide a voltage output signal, ensure that the manufacturers datasheet is reviewed to confirm compatibility, as well as wiring and configuration details specific to that sensor.
The wiring schematic diagram below depicts the wiring connections and how the voltage signal is measured by the GX Tank 140: between “In” (+) and “GND” (-).
The table below shows the wiring connections in a tabular format, including the tank sensor connection names and common wiring colours.
GX Tank 140 | Tank Sensor | |
|---|---|---|
Connection name | Common wiring colours** | |
Vout / 24V* | Excitation (+), Vs+ | Red |
In | Signal (0 to 10V or 0 to 5V), Output | Varies |
GND | Excitation (-), Vs- | Black/Blue |
Notice
*Vout: Channels 1 and 2, 24V: Channels 3 and 4
** Confirm wiring colours with the tank sensor datasheet before connection
2.2.3. Current output sensors (4 to 20mA)
Before connecting tank sensors that provide a current output signal, ensure that the manufacturers datasheet is reviewed to confirm compatibility, as well as wiring and configuration details specific to that sensor.
The wiring schematic diagram below depicts the wiring connections and how the current signal is measured by the GX Tank 140: there is a load (RL) between “In” and “GND” which is used as a shunt to establish the current flow (based on the voltage drop across RL and the known resistance).
Accordingly, the sensor must be connected to “Vout/24V” and “In”, while “GND” can be left unconnected.
The table below shows the wiring connections in a tabular format, including the tank sensor connection names and common wiring colours.
GX Tank 140 | Tank Sensor | |
|---|---|---|
Connection name | Common wire colours** | |
Vout / 24V* | Excitation (+), Vs+ | Red |
In | Excitation (-), Vs- | Black/Blue |
GND | Not connected | N/A |
Notice
*Vout: Channels 1 and 2, 24V: Channels 3 and 4
** Confirm wiring colours with the tank sensor datasheet before connection
2.2.4. Terminal blocks
To physically connect the tank sensor wiring to the pluggable terminal blocks, it is advised to use a crimped bootlace ferrule. Bootlace ferrules can be inserted directly into the spring loaded terminals on the pluggable terminal blocks and reduce the risk of wiring issues.
Bare stranded copper wire can be used (without a bootlace ferrule), however care must be taken during the installation process; strip the insulation to reveal at least 10mm of bare copper wiring, then fully depress the orange tab on the pluggable terminal block with a precision screwdriver while the wiring is carefully inserted (ensure that there are no stray strands).
Once the wiring is properly installed/seated within the spring loaded terminals on the pluggable terminal blocks, the orange tab must be fully depressed with a precision screwdriver in order to remove the secured wiring/bootlace ferrule (if ever necessary).
The pluggable terminal blocks can be easily connected and disconnected to/from the mating sockets on the GX Tank 140 unit as required, for installations in space constraint locations it can be easier to connect the wiring to the pluggable terminal blocks independently, before they are plugged in.
2.2.5. Sensor cable
It is recommended to use shielded twisted core cabling between the tank sensor and the GX Tank 140 unit, in order to prevent electrical interference/noise from the external environment from falsifying/effecting the measurements.
Most sensors are already equipped with shielded cabling and may be directly connected if there is sufficient length.
It is also recommended to route the tank sensor cabling as far as practical away from DC and AC power cabling and to ground the cable shield on bare metal of the vehicle or boat.
2.2.6. Electrical Isolation
The USB cable is electrically isolated from the sensors, as such there is no risk of ground loops occurring between the sensors and the USB socket of the GX device.
The "GND" connections of all four channels are internally connected, they are not individually isolated from each other.