2.21
2.7 BATTERY BACK-UP
Analysers fitted with microprocessor board 01100918C or 01100918D and software version
0110068X (X = 1,2 or 3) do not need battery back-up of the memory. These analysers have serial
number of the Control unit 1101/2301 and above and serial number of Interface unit 1102/201 and
above.
Earlier analysers have to have batteries fitted to power the microprocessor memory during periods
when electrical power is removed from the analyser. Failure to fit, or renew batteries, will result
in loss of memory. This includes calibration constants, alarm levels, allocation of alarm levels to
relays etc.
The batteries are mounted in a holder below the card frame. Batteries are not supplied with the
analyser. Section 4.5 gives details of how to fit the batteries.
Note that in separated systems the batteries are fitted in the Interface Unit.
Battery specification: Size - AA
Type - Alkaline, non-rechargeable
Voltage - 1.5V
Quantity - 3
The batteries should be changed annually. They have sufficient capacity to power the memory
continuously for a minimum of 12 months.
Note: If the analyser is to be taken out of service and stored for a period longer than 6
months the batteries should be removed to prevent leakage and corrosion.
2.8 TRANSDUCER TO CONTROL OR INTERFACE UNIT INTERCONNECTIONS
Except for the close coupled analyser it is necessary to install cables to connect the various units
together. Two cables connect the Transducer unit to the Control or Interface unit, a signal cable
and a heater supply.
The 1131 Transducer unit has one terminal box for both cables, the 1132 and 1133 have a
separate terminal box for the heater cable.
2.8.1 Signal Cable
The signal cable is a multicore instrumentation cable carrying analogue signals from the
Transducer unit to the Control or Interface unit. It is terminated in the terminal box at the
Transducer unit and on the analogue amplifier board (01100 925B) in the Control or Interface unit.
The screen must be earthed at the Control unit end only.
This cable connects intrinsically safe circuits and special conditions apply for analysers installed
on hazardous applications. These conditions vary depending on certification and are detailed
below.
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