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1. DESCRIPTION
The BA338C is an intrinsically safe, externally
powered pulse input 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.
The BA338C has been certified intrinsically safe by
European Notified Body Intertek Testing Services
(ITS) to the ATEX Directive 94/9/EC.
For use in the USA the instrument also has
intrinsic safety and nonincendive FM approval –
see Appendix 1.
Housed in a robust 72 x 144 panel mounting DIN
enclosure, the BA338C has an IP65 static
dissipative front panel and is supplied with a
gasket to seal the joint between the instrument and
the panel.
2. OPERATION
Fig 1 shows a simplified block diagram of a
BA338C. The instrument accepts pulses from a
single source and after scaling displays the total
number of pulses received and their rate on
separate displays. When connected to a pulse
output flowmeter the BA338C will provide an
accurate display of total flow and the rate of flow.
The BA338C has two sets of input terminals for
connection to high or low level voltage pulses, a
switch contact, an open collector output or to a two
wire proximity detector. The instrument may
therefore be used with almost any pulse output
flowmeter. The total display may be reset to
zero by a remote switch contact or from the front
panel push-buttons.
Optional accessories enable the flow rate to be
transmitted to other equipment as an isolated
4/20mA analogue signal and the total flow to be
transmitted as a pulse signal. Optional alarms,
which may be programmed to function on the rate
or total displays, further extend the instrument’s
applications.
Fig 1 Simplified block diagram of BA338C
2.1 Initialisation
Each time power is applied to the instrument
initialisation is performed. After a short delay the
following display sequence occurs:
All segments of the display are activated for
2 seconds.
The product firmware part number and
version number are displayed for 2 seconds.
Rate display and totaliser start to
function using calibration information
stored in the instrument's permanent
memory.
2.2 Controls
The BA338C is controlled and calibrated via four
front panel push-button switches. In the display
mode i.e. when the instrument is displaying rate
and total flow the switch functions are:
Description of Switch Functions
E+ Down While these buttons are pushed the
total display will show the least
significant eight digits of the grand total,
and the grand total annunciator will be
activated.
E+Up While these two buttons are pushed the
total display will show the most
significant eight digits of the grand total
and the grand total annunciator will be
activated.
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