Grass Valley SMS-6000 Series - Manual (Page 33)

1-16
Section 1 — Introduction
Ground and Power Fail Alarms
A terminal strip is provided on some units to select how the system is
grounded.
Separate connections are provided on the rear of audio frames for:
■ TECH 0V Internal technical 0V
■
GND To ground pin of power connector and to the
external metalwork
■
O/P SCREENS The 16 shield pins on the two Output connectors are
connected together and to this pin
■
I/P SCREENS Connection to the shield pins of the two Input
connectors
CAUTION
The TECH 0V must be connected to an earth ground in order to operate the
equipment safely.
The equipment is shipped from the factory with the TECH 0V and GND
linked together to ensure that the electronics hardware is properly
grounded.
The input and output shields terminals are provided to avoid the problems
of ground loops caused by differences in the ground potentials on the
shields (screens) of the input cables and the output cables. It is common to
connect the O/P SCREENS to GND at the driving end, but some installers
prefer to connect I/P SCREENS to GND instead. However it is inadvisable
to connect both sets of shields to GND.
On the 3RU video frame the terminal strip has the following connections:
■ TECH 0V Internal technical 0V
■
GND To ground pin of power connector and to the
external metalwork
■
POWER FAIL Pair of contacts held closed, so long as both power
supplies are installed, switched on and working
CAUTION
The TECH 0V must be connected to an earth in order to operate the equipment
safely.
The equipment is shipped from the factory with the TECH 0V and GND
linked together to ensure that the electronics hardware is properly
grounded.