BEKA BA368C, Manual

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4.1 DESCRIPTION
When programmed as a tachometer the BA368C
will display rotational speed in revolutions per
second, minute or hour. Linear speed in
engineering units may also be displayed. To assist
with routine maintenance, a run-time clock records
the number of hours the monitored machinery has
been operating. The displayed run-time may be
reset to zero from the instrument front panel, or by
closure of a remote contact. The instrument also
maintains a grand total run-time which can only be
reset from within the programme menu.
An optional 4/20mA output current sink may be
programmed to produce a linear output
proportional to any part of the displayed speed
range.
Two optional alarm outputs may be programmed to
provide speed warnings, or from the run-time
display to indicate when routine maintenance is
due.
4.1.1 Initialisation and loss of power
When power is applied to a BA368C tachometer,
following initialisation the instrument will start
functioning using the programmed parameters. If
during operation the power supply is interrupted,
all programme parameters and the run-time will be
stored in permanent memory.
4.1.2 Controls
The BA368C tachometer is controlled and
calibrated via four front panel push-button
switches. In the display mode i.e. when the
instrument is displaying speed the switch functions
are:
Description of Switch Functions
E+Down While these buttons are pushed the
speed display will show the run-time
grand total and the grand total
annunciator will be activated.
Down Resets the run-time display to zero
+Up when these two push-buttons are
operated simultaneously for more than
two seconds.
Selectable function from programme
menu.
See section 4.5.10
P+Down While these buttons are pushed the
instrument will display the firmware
and version numbers plus the
programmed function.
Note : When optional alarms are fitted, the
BA368C may be programmed to provide direct
access to the alarm setpoints from the display
mode by operating the
P + Up push-buttons.
See section 4.6.10
4.1.3 Displays
The BA368C tachometer has two digital displays
and associated annunciators, plus a pulse input
indicator.
Speed Shows speed on the larger
display six digit display.
Run-time Shows the time that monitored
display machinery has been operating on
smaller six digit display. May be
turned off – see 4.5.5
Pulse input This disc in the lower left hand
indicator 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.
Reset Activated while run-time display
Annunciator is being reset to zero.
Hold Activated when input frequency
Annunciator is below the clip-off threshold at
which the run-time clock stops
operating.
Grand total Activated while run-time grand
Annunciator total is being displayed.
Alarm Activated when optional alarm
Annunciators is activated
4.2 SYSTEM CERTIFICATES
In addition to the ATEX EC-Type Examination
Certificate, ITS have issued two system
certificates. One defines how the BA368C may be
used with Zener barriers and the other with
galvanic isolators.
Interface Certificate No
Zener barriers Ex01E2007
Galvanic isolators Ex01E2008
This section interprets these system certificates
and illustrates how to design tachometer systems
with Zener barriers and galvanic isolators.
System certificates are Certificates of Conformity
which are primarily issued for guidance in the UK.
They do not form part of certification to the
European ATEX Directive.