BEKA BA577E-SS, Руководство пользователя

Страница: 28 / 38

28
8. OPERATION AS A CLOCK
When configured as a clock the BA577E-SS can
display local time in a variety of twelve or twenty four
hour formats. The displayed time can be adjusted
via the front panel push buttons which may be
protected by a user definable four digit security code
to prevent unauthorised or accidental adjustment.
The clock may be synchronised to an external time
standard via the instrument's reset terminals. When
these two terminals are connected together by an
external switch contact, the clock display will be
reset to a preconfigured time and will resume
running from this time when the contacts are
opened.
When fitted with the optional galvanically isolated
control outputs the clock can be configured to turn
each solid state output
on and off twice during each
twenty four hour period.
Fig 13 shows a simplified block diagram of the
BA577E-SS configured as a clock.
The instrument can be supplied with the following
factory fitted accessories:
Backlight Internally powered
Dual isolated control outputs
Fig 13 BA577E-SS block diagram with
clock configuration.
8.1 Initialisation and loss of power
Each time power is applied to a BA577E-SS
initialisation is performed. After a short delay the
following display sequence occurs:
All segments of the display are activated
Instrument starts functioning using the
configuration stored in the instrument's
permanent memory.
Following initialisation, the instrument will display a
flashing display which is a request for the local time
to be entered. The clock will not start to function
until a display time has been entered, or the remote
reset contacts are closed and opened to synchronise
the clock to a preconfigured time.
If during normal operation the power supply is
interrupted for more than 30ms, the display will
return to the flashing condition and the display time
will have to be re-entered. Longer interruptions may
be tolerated by powering the Clock from an
instrument supply with large output capacitance.
8.2 Controls when configured as a clock
The BA577E-SS clock is configured and adjusted via
four front panel push buttons. In the display mode
i.e. when the instrument is displaying time, the push
button functions are:
(
+
&
Shows in succession, firmware
version number, instrument function
CLoc
and output accessories that
are fitted:
-A
Dual Control Outputs
(
+
)
Access to configuration menu
Note: When optional control outputs are fitted, the
BA577E-SS clock may be configured to provide
direct access to the control output
on and off times
from the display mode when the
(
and
*
push
buttons are operated. - see section 8.4.13
8.3 Displays when configured as a clock
The BA577E-SS clock has a single digital display
plus annunciators.
Time Shows time in selected 12 or
display 24 hour format.
Reset Activated while clock is being
annunciator synchronised and external
reset contacts are closed.
Control output Show status of both optional
annunciators control output.