Start-Up - ABB AK101 User Manual

8 START-UP

Warning. When the apparatus is connected to its
supply, terminals may be live and the opening of covers
or removal of parts (except those to which access may
be gained by hand) is likely to expose live parts.
Note. CO is refered to throughout this manual as the
2
purge gas. However, other gases such as Argon or
Nitrogen may be used instead.
8.1 Instrument Start-Up
In normal operation, the range selector switch is set to
position 1 and the instrument displays the
– see Section 9.2. This is a general use page in which the
Page
alarm set points may viewed but not altered. To change an alarm
set point or program a parameter refer to Section 10. A 5-digit
Security Code is used to prevent unauthorized access to
programmable parameters. The value is preset at 00000 to allow
access during commissioning but should be altered to a unique
value, known only to authorized operators, as described in the
– see Section 10.3.3.
Setup Outputs Page
When all the required wiring connections and electrical checks
have been made correctly, switch on the power supplies to the
various units as follows:
1) Switch on the supply to the PSU.
2) Switch on the supply to the 6553 Display Unit.
3) If cubicle-mounted, switch on supply via the isolator
switch, if fitted.
8.2 Alarm Set Point
8.2.1 Type of Alarm Action
The alarm relay coil is energized during normal non-alarm relay
states and is de-energized upon recognition of an alarm
condition, thereby providing 'fail-safe' alarms. For example, with
Alarm 1 set point = 95.0%, when the display is indicating greater
than 95.0% (plus hysteresis), Alarm Relay 1 is energized and
Alarm 1 LED is OFF. When the display indicates less than 95.0%
(minus hysteresis), Alarm Relay 1 is de-energized and Alarm 1
LED is ON. This operating mode ensures that an alarm condition
is signalled in the event of a mains power failure. Repeat the
procedure for Alarm Relay 2 set point = 90.0%.
8.2.2 Hydrogen Alarm Set Point
It is recommended that the hydrogen alarm set-points are based
on a reducing percentage of hydrogen as it is displaced by air
entering the application plant. This can be achieved by setting
Alarm 1 and Alarm 2 to give ample warning of the development
of a potentially explosive mixture. Factory settings are Alarm 1 =
95.0% and Alarm 2 = 90.0%.
The procedure is as follows:
Access the programming pages (Section 10) and set the alarm
8.3 Electrical Calibration
The instrument is factory calibrated for electrical voltage signal
input. No adjustment is normally necessary for correct
functioning of the display unit. If electrical calibration is required,
a voltage source capable of supplying 0.00 mV and 10.00 mV is
needed. Disconnect the katharometer input from the display unit
and the voltage source signal applied according to the
instructions in the
Range 1 Operating
8.4 Gas Calibration
8.4.1 Introduction
Before putting the system on-line, it is recommended that a
calibration check for the 'zero' reading is made using calibration
standard sample gas.
The 'zero gas' is marked permanently on the data plate of the
katharometer unit. This gas, when passed through the
katharometer, gives a zero millivolt output. To provide a fail-safe
condition for hydrogen purity, the zero gas is 85% hydrogen-in-
nitrogen mixture. If power is lost to the katharometer, a hydrogen
purity alarm condition occurs on the display unit.
Full scale output from the katharometer is obtained by a 100%
hydrogen gas sample and no adjustment of the katharometer
output is normally required. The maximum signal for the full scale
reading is sealed during manufacture and must not be altered by
users.
8.4.2 Purge Gas
When a purge gas katharometer forms part of the 6553 System,
the startup procedure is as follows:
1) Pass suitable calibration quality gas through the purge gas*
Electrical Calibration Page
Note. The 4689 instruments incorporate a two-point
calibration sequence requiring both zero and span
inputs for a calibration. It is not possible to adjust either
the range zero or the range span scale points
independently.
Notes.
1. The procedure outlined here is not normally
necessary as the ranges have been set at the
factory.
2. Test for leaks in accordance with the requirements of
the responsible authority after making any gas
connections.
katharometer, on the appropriate katharometer analyzer
panel. The gas should be at the normal working pressure of
the sample gas. This provides the correct flowrate of purge/
sample gas as set previously.
*Note. Purge gas options include:
CO (Carbon dioxide)
2
N (Nitrogen)
2
Ar (Argon)
– see Section 10.
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