BEKA BA334D, Руководство пользователя

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4
Down Resets the total display to zero
+Up when these two push-buttons are
operated simultaneously for two
seconds.
Selectable function from
programme menu.
See section 6.12
P While these buttons are pushed the
+ Down instrument will display the firmware
part number and version number.
Note : When optional alarms are fitted, the
BA334D may be programmed to provide direct
access to the alarm setpoints from the display
mode when the P + Up push-buttons are
operated – see section 9.2
2.3 Displays
The BA334D has two digital displays and
associated annunciators, plus a flow indicator
as shown on page 1.
Rate Shows the flow rate on the
Display smaller six digit display.
Total Shows the total flow on the
display larger eight digit display. Set
to zero when local or remote
reset switch is operated.
Flow This disc in the lower left
indicator hand corner of the display 'rotates'
for two seconds each time an
input pulse is received.
Therefore when the pulse input
frequency exceeds 0.5Hz the
disc appears to rotate
continuously.
Hold Activated when input
Annunciator frequency is below the clip-off
threshold.
Reset Activated while instrument is
Annunciator being reset.
3. INTRINSIC SAFETY CERTIFICATION
3.1 ATEX certificate
The BA334D has been issued with an EC-Type
Examination Certificate by Notified Body
Intertek Testing Services (ITS) confirming
compliance with the European ATEX Directive
94/9/EC for Group II, Category 1, gas and dust
atmospheres, EEx ia IIC T5. The instrument
bears the Community Mark and subject to local
codes of practice, may be installed in any of
the European Economic Area (EEA) member
countries. ATEX certificates are also
acceptable for installations in Switzerland.
This manual describes installations in gas
hazardous areas which conform with BS
EN60079:Part14:2003 Electrical Installation in
Hazardous Areas. When designing systems
for installation outside the UK, the local Code
of Practice should be consulted.
For use in the presence of combustible gas,
please refer to Appendix 1 which describes
installations complying with BS EN 50281-1-
2:1999.
3.2 Power supply
When installed in a hazardous area the
BA334D must be powered via a Zener barrier
or galvanic isolator from a dc supply located in
the safe area.
The input safety parameters of terminals 1 and
2 are:
Ui = 28V dc
Ii = 100mA dc
Pi = 0.7W
Any certified Zener barrier or galvanic isolator
with output safety parameters within these
limits may be used. The two system
certificates provide guidance to help selection
of suitable devices.
The maximum equivalent capacitance and
inductance between terminals 1 and 2 is:
Ci = 20nF
Li = 20µH
To determine the maximum permissible cable
parameters the above figures should be
subtracted from the maximum permitted cable
parameters specified for the Zener barrier or
galvanic isolator powering the BA334D.