90
5.5.10 Adjusting control output setpoints
while displaying time
Direct access to the control output setpoints from
the clock display mode is obtained by operating
the
P
and
Up
push-buttons simultaneously as
shown in Fig 5.4. If the setpoints are not
protected by a security code the control output
setpoint prompt 'OP1: On1' will be displayed. If
the setpoints are protected by a security code,
'COde' will be displayed first. Pressing
P
again
will enable the control output security code to be
entered digit by digit using the
Up
and
Down
buttons to change the flashing digit and the
P
push-button to move control to the next digit. If
the correct code is entered pressing
E
will then
cause alarm setpoint prompt 'OP1: On1' to be
displayed. If an incorrect security code is
entered, or a button is not pressed within ten
seconds, the instrument will automatically return
to the display mode.
Once within the menu pressing the
Up
or
Down
buttons will scroll through all the setpoints. When
the required setpoint is displayed pressing
P
will
reveal the existing setpoint time. This may be
adjusted using the
Up
and
Down
push-buttons
and the
P
button to move control to the next digit.
When the required time has been entered,
pressing
E
will return the display to the setpoint
identification from which another setpoint may be
selected, or the clock may be returned to the
display mode by pressing
E
again.
Each of the two control outputs has two or four
setpoints depending upon whether the output has
been programmed to turn on & off once or twice
in each 24 hour period. – see 5.5.7
Notes:
Direct access to the control output
setpoints is only available when the menu is
enabled - see section 5.5.9
Seconds are always displayed while adjusting the
setpoints.
Fig 5.4 Setpoint adjustment from the clock
display mode
5.6 APPLICATION
This section describes a typical application in
which a 24 hour clock with a HH:MM format is
required within a hazardous area. To comply
with auditing requirements, this, and number of
other BA364D clocks are to be automatically
synchronised at 12:00 each day. To prevent
accidental adjustment the instrument programme
menu is to be protected by security code 1112
Fig 5.5 shows the simplest Zener barrier interface
and illustrates how a number of clocks may be
synchronised. Terminals 2 and 8 are
interconnected within the BA364D so only one of
them needs to be connected to the Zener barrier
busbar.
When the synchronising contact is closed all the
BA364D clocks will display the programmed reset
time, in this example 12:00. When the contacts
open all the clocks will start running. This contact
may be a PLC output programmed to close at
11:59:58 and to open at 12:00:00
