Guralp Systems CMG-5TD - Manual (Page 14)

CMG-5TD Digital Accelerometer Operation
5.3 Installation in hazardous environments
The fully enclosed aluminium case design of the 5T instrument makes it
suitable for use in hazardous environments where electrical discharges due to
the build up of static charge could lead to the ignition of flammable gasses.
To ensure safe operation in these conditions, the metal case of the instrument
must be electrically bonded ('earthing') to the structure on which it is
mounted, forming a path to safely discharge static charge.
Where electrical bonding ('earthing') is required during the installation of a 5T
instrument, the central mounting hole that extends through the instrument
should be used as the connection point. This is electrically connected to all
other parts of the sensor case. Connection can be made either via a cable from
a local earthing point terminated in a 8 mm ring tag or via the mounting bolt
itself.
5.4 Orientation
Use the handle and north indicator inscribed in the handle to orient the
CMG-5TD.
5.5 Levelling
Use the large socket-cap screws to level the CMG-5TD. Remove the upper
portion of the mounting plate, then tighten down the concrete bolt, securing
the base. Re-attach the upper portion of the mounting plate to the CMG-5TD.
Check orientation and level and then tighten down the levelling locking nuts.
5.6 Power supply considerations
The CMG-5TD will operate from 12-36 V DC. The CMG-5TD draws around
185 mA from a 12 V power supply.
5.7 Connections
Connect the GPS receiver to the CMG-5TD using the cables provided.
Connect the DE9 connector of the grey/blue power/data cable to a PC or
communications device.
Connect the power supply (12 to 36 V DC) to the bare ends of the grey part of
the grey/blue power/data cable. The red core should go to the positive
terminal or the terminal marked '+' and the black core should go to the
negative terminal or the terminal marked '-'. The power supply should be
capable of sourcing 200 mA.
MAN-050-0005 14 Issue D - April 2013