INSTALLATION
2-8
Interface bus connection
The cables for the interface bus use special male-female connectors at both ends. This
allows several connectors to be stacked one on top of another permitting several cables to be
connected to the same source and secured by a lockscrew mechanism. Too large a stack,
however, may form a cantilevered structure which might cause damage and should be avoided.
The piggyback arrangement permits star or linear interconnection between the devices with the
restriction that the total cable length for the system must be:
(1) No greater than 20 m (65 ft).
(2) No greater than 2 m (6 ft) times the total number of devices (including the
controller) connected to the bus.
RACK MOUNTING
The instrument, which is normally supplied for bench mounting, may be mounted in a
standard 19 inch rack (see Chap. 1 'Optional Accessories'). There are two slide rack mounting
kits to accommodate different depths of cabinet. These kits include full fitting instructions. A
rack mounting kit without slides is also available which contains front panel mounting brackets
only.
BATTERY REPLACEMENT
The instrument contains a real-time clock which is powered by a lithium battery when the
normal power is removed. Although battery life can extend to five years, this will depend on
conditions of use, e.g. battery life is reduced as the temperature is increased. To avoid loss of
data it is recommended that the battery is replaced every two years.
Replace the battery as follows:
(1) Ensure that the instrument is switched on; this will provide power for the
non-volatile memory while the battery is replaced. If this is not possible, the
clock will continue to run for approximately 30 seconds, whilst the replacement is
made.
(2) Using a coin or suitable tool, unscrew the battery compartment cover at the rear of
the instrument.
(3) Remove the battery, noting its orientation. Insert the replacement, then replace
the battery compartment cover.
The replacement battery should be SAFT L56 or equivalent. This is a lithium 3.5 V type,
rated at 1800 mAH, size AA. If a lithium battery is unobtainable an alkaline battery can be used
but it will have a shorter life. A suitable battery can be obtained from Aeroflex (part number
23711/106).
CAUTION -
ROUTINE MAINTENANCE
Safety testing and inspection
In the UK, the ‘Electricity at Work Regulations’ (1989) section 4(2) places a requirement
on the users of equipment to maintain it in a safe condition. The explanatory notes call for
regular inspections and tests together with a need to keep records.
The following electrical tests and inspection information is provided for guidance
purposes and involves the use of voltages and currents that can cause injury. It is important that
these tests are only performed by competent personnel.
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