This feature tech-tip will describe the functionality and setup of the Advanced Relay Mode using the ( a | ( b & c) ). logic.
In the Advanced Relay Mode, only Low and High Alarm conditions can be set, however, a Window Alarm can be achieved through proper setup. A Window Alarm is used to detect when the signal input is between a user-selected range.
NOTE: If a Window Alarm is required in the Advanced Relay Mode, two relay sources (eg. Source1, Source2) must be used for proper alarm functionality. This will effectively allow the user to only monitor 2 channels versus 3 channels when using Low or High Alarms.
Consider the hypothetical application below:
If the mV reading of the feed (incoming) water is below 300 mV
OR
if
the pH of the feed (incoming) water is between 6 AND 8 pH
then
trigger an alarm for the technician or other automated equipment to take further action.
Parameter Setup in the 8900 Multi-Parameter Controller
Relay 1 Source:
Multiple
Relay 1 Mode:
Advanced
Relay 1 Operator:
( a | ( b & c) )
a = Relay 1 Source 1, b = Relay 1 Source 2, c = Relay 1 Source 3
Relay 1 Source1:
ORP1
Parameter setup to monitor the mV in the feed (incoming) water.
(a)
Relay 1 Mode 1:
Low
Relay 1 Setpnt1:
+300 mV
Relay 1 Hys 1:
1 mV
Relay 1 Source2:
pH2
Parameter to monitor the lower pH range in the feed (incoming) water.
(b)
Relay 1 Mode 2:
High
Relay 1 Setpnt2:
6.00 pH
Relay 1 Hys 2:
0.5 pH
Relay 1 Source3:
pH2
Parameter to monitor the upper pH range in the feed (incoming) water.
(c)
Relay 1 Mode 3:
Low
Relay 1 Setpnt3:
8.0 pH
Relay 1 Hys 3:
0.5 pH
Relay 1 Delay:
0.0000 sec
The symbol "|" refers to OR logic and the "&" symbol refers to AND logic. If the condition for source "a" is true OR if the condition for source "b" AND "c" is true, then trigger the relay.
