1. DESCRIPTION
The BA354NE is a Type nA certified 4/20mA loop
powered Rate Totaliser primarily intended for use
with flowmeters. The instrument simultaneously
displays the rate of flow and the total flow in
engineering units on two separate displays. It is
loop powered but only introduce a 1.2V drop, which
allows it to be installed into almost any 4/20mA
current loop. No additional power supply or battery
is required.
The Rate Totaliser has been issued with an Ex nA
and Ex tc Type Examination Certificate by Notified
Body Intertek Testing and Certification Ltd which has
been used to confirm compliance with the European
ATEX Directive 94/9/EC.
The main section of this manual describes
application ins gas hazardous areas, applications in
combustible dust atmospheres are described in
Appendix 1.
For international applications the BA354NE has
IECEx certification which is described in Appendix 2.
Housed in a robust IP66 glass reinforced polyester
(GRP) enclosure with an armoured glass window,
the BA354NE is surface mounting, or may be pipe
mounted using one of the accessory kits.
2. OPERATION
Fig 1 shows a simplified block diagram of a
BA354NE Rate Totaliser. The 4/20mA input current
flows through resistor R1 and forward biased diode
D1. The voltage developed across D1, which is
relatively constant, is multiplied by a switch mode
power supply and used to power the instrument.
The voltage developed across R1, which is
proportional to the 4/20mA input current, provides
the input signal for the analogue to digital converter.
Each time a 4/20mA current is applied to the
instrument, initialisation is performed. After a short
delay the following display sequence occurs which
takes about twelve seconds:
All segments of the display are activated
Loading message displayed
Configuration message displayed
Model and firmware version displayed
Rate Totaliser starts functioning, using
configuration information stored in
instrument’s permanent memory. Unless
total and grand total displays have been
reset to zero, new flow will be added to
the existing totals.
Fig 1 Simplified block diagram of BA354NE
2.1 Controls
The BA354NE is controlled and calibrated via four
push buttons which are located behind the
instrument control cover, or as an option on the
outside of the instrument control cover. In the
operating mode i.e. when the instrument is
displaying rate and total flow the push button
functions are:
Summary of Push Button Functions
P
Displays input current in mA or as a
percentage of span. Modified when
optional alarms are fitted.
▼
Shows rate display calibration at 4mA
input.
▲
Shows rate display calibration at 20mA
input.
E
Shows time since instrument was
powered or total display was reset.
E
+
▼
Grand total –
displays least significant 8 digits
E
+
▲
Grand total –
displays most significant 8 digits.
▼
+
▲
Resets
total
display
Configurable function
P
+
▼
Shows firmware version
P
+
▲
Alarm setpoint access
Configurable function
P+E
Access to configuration menu
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