Hach 900 MAX User Manual

Page of 160
Section 6
Page 91
8990cm.fm
Alarm Relays
Figure 27
Single Relay Wiring Inside the Relay Junction Box
6.4.2 Alarm Relays Programming
Program alarms activate based on certain conditions (low battery, low 
memory, etc.). When an alarm is tripped, an action is initiated (report via 
modem, dial a pager, or set a relay). There are two types of alarms: Trouble 
Alarms and Set Point Alarms.
6.4.2.1 Trouble Alarms
Trouble Alarms initiate an action when a trouble condition occurs. For 
example, a relay may close when the memory is full. Refer to 
 for more information on trouble alarms.
1.
From the Main Menu, select 
SETUP > ADVANCED OPTIONS > ALARMS.
2.
 Select one of the trouble conditions.
3.
Select an action to occur when the alarm is activated. The table below 
lists each Trouble Condition. Refer to 
 for causes 
and solutions. 
6.4.2.2 Set Point Alarms
Set Point Alarms look for trip points to be reached (either high or low or both) 
before initiating an action. For example an initiated action may be the closing 
of a relay when the water level exceeds 60 cm (24 in.) or drops below 10 cm 
(4 in.) Set Point Alarms activate when a user-definable high and/or low set 
point is reached. 
Trouble Conditions:
Low Main Battery
Memory Battery
Low Slate Memory
Slate Memory Full
Modem Failure
Missed Sample
Purge Failure
Jammed Distributor
RS485 Timed Out
Alarm Actions:
Set Relay #1
Set Relay #2
Set Relay #3
Set Relay #4
Report Via Modem