Document No: LT0499
RDU Mk2 Installation & Programming Manual
Programming Part 2
Issue 1.02
8 April 2015
Page 7-19
Example 3 - Use of Timers
Timers 1 to 64 are "seconds based" with a range of 0 to 250 seconds, and timers 65 to 72
are "minutes based" with a range of 0 to 250 minutes.
A certain building has an outdoor yard with a very loud sounder. It is too loud to be left on
continuously. For any alarm in the premises it is desired to give one set of three 5 second
bursts on the sounder with 5 second delays between the bursts.
Solution:
A relay (say R7) is assigned to switch the sounder. Three pulse timers (say T5, T6, T7) are
required.
T5[P0:5] = ALM
T6[P10:5] = ALM
T7[P20:5] = ALM
R7 = T5 + T6 + T7
Example 4 - Use of Timer To Make Continuous Pulsing
A building has a loud "hooter" to attract the operator to the RDU. The hooter is relay driven
and must pulse 1 second on, 1 second off, on occurrence of any alarm until it is
acknowledged.
Solution:
Use a timer to make a 1 second on, 1 second off oscillator. An ancillary relay output (say
AR1) and a timer (say T1) are assigned. The MUA (MAF unacknowledged alarm) is used as
follows:
T1[S1:1] = ^T1
MUA
AR1 = T1.MUA
ALARM ACKNOWLEDGE
7.3.6
ENTERING EQUATIONS
Entering equations from the keypad is similar to entering text names, but includes entering
logical operators and parentheses with specific keys.
When an output (e.g., Relay 65
) is selected, press "EDIT", "ENTER" or "►" to enable
equation entry mode for that output.
There are two cursors shown on the display, one on the top line to indicate where the next
item will be entered in the equation, and one on the bottom line to indicate which operand is
selected. The active cursor is a large block character
█
and the inactive cursor is a small
block character
. The active cursor
█
may be moved using the ◄ ► arrow keys. The
SET/EDIT key is used to swap the active cursor between the top and bottom lines.
Parentheses and the NOT operator may also be entered directly using the NOT, RECALL
and PRINT keys. The bottom line of the display shows one of eight sets of operands.
These may be scrolled through using the ▲ and ▼keys to choose the desired set. Note that
numbers and operators can be entered directly from the keypad.