BEKA BA368C, Manual

Page: 65 / 93

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 BA368C 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 BA368C may be reset from both the safe
and the hazardous area.
4.4.4 Optional 4/20mA output
The BA368C 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 BA368C 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 BA368C 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