65
4.4.3 Resetting the run-time display
When activated the run-time display can be reset
to zero by connecting terminals 7 & 8 together.
To achieve reliable resetting the contacts must
close for at least one second.
Resetting may be accomplished by any
mechanically operated switch located in the
hazardous area providing it can withstand a 500V
rms insulation test to earth for one minute. No
galvanic isolator is required.
The BA364D may also be reset from within the
safe area. Any switch may be used, but a
galvanic isolator or intrinsically safe relay is
required to transfer the contact closure into the
hazardous area. See system certificate for a list
of some devices that may be used. Fig 4.2
illustrates how the BA364D may be reset from
both the safe and the hazardous area.
4.4.4 Optional 4/20mA output
The BA364D can be supplied with an isolated
4/20mA current sink which may be programmed
to produce an analogue output proportional to
any part of the speed display. See section 4.7
4.4.5
Optional alarm outputs
The BA364D can be supplied with two isolated
solid state switch alarm outputs which may be
independently programmed as high or low, speed
or run-time alarms with normally open or closed
outputs. These outputs may be used to switch
certified intrinsically safe devices within the
hazardous area, or the contacts may be
transferred to the safe area via a galvanic
isolator. See section 4.6
4.5 PROGRAMMING
Throughout this manual push-buttons are shown
in italics e.g.
P
or
Up
push-button, and legends
displayed by the instrument are shown within
inverted commas e.g. 'SEt' and ' dISPLAY'.
4.5.1 Accessing programme functions
Access to the programme menu is obtained by
operating the
P
and
E
push-buttons
simultaneously. If the BA364D is not protected
by a security code the first parameter ‘Function’
will be displayed. If a security code other than
the default code 0000 has already been entered,
the instrument will display 'COdE'. Press
P
to
clear this prompt and enter the security code for
the instrument using the
Up
or
Down
push-button
to adjust each digit, and the
P
push-button to
move control to the next digit. If the correct code
has been entered pressing
E
will cause the first
parameter ‘Function’ to be displayed. If an
incorrect code is entered, or a push-button is not
operated within ten seconds, the instrument will
automatically return to the display mode.
Once within the main programme menu the
required parameter can be reached by scrolling
through the menu using the
Up
and
Down
push-
buttons as shown by the tachometer programme
structure shown in Fig 4.3.
This section summarises all the tachometer
programmable parameters excluding the optional
alarms and 4/20mA output. When read in
conjunction with Fig 4.3 it provides a quick aid for
programming the instrument. If more detail is
required, each section contains a reference to a
full description of the function.
Programming details for the alarms and 4/20mA
output are contained in sections 4.6.1 and 4.7
