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13.8.2 Deadband
After the setpoint is established, the relay's deadband must also be set. "Deadband" refers to the
amount of conductivity or ORP above and below the setpoint—a range within which the controller will not
react. Due to continuous fluctuations in the conductivity and ORP level, it is necessary to have this
deadband range or stable readings will be difficult to obtain. The Deadband should be a small
percentage of the setpoint. Half the deadband amount will be automatically put above the setpoint, and
the other half below it.
For example, a Conductivity setpoint of 1000 µS with a deadband of 20 µS would result in the relay
turning on at 1010 uS and turning off at 990 µS.
Use the keypad numbers to enter the proper deadband setpoint and press ‖ENT‖. When
finished, you will automatically be switched to the OVERFEED TIME alarm screen.
13.8.3 Overfeed Time
The OVERFEED TIME alarm is designed to notify the operator of a problem in the chemical feed system
such as, a pump has lost its prime or there is no chemical in the drum. It will also protect the system
from overfeeding chemical when the indicated conductivity or ORP does not display a change in actual
conductivity or ORP. The OVERFEED timeout function will display a visual alarm on the display and it
will turn off the relay. If a relay is configured as an alarm relay, the OVERFEED TIME alarm will
energize the alarm relay. To disable this function set the OVERFEED time to 0:00.
Use the keypad numbers to enter the time in hours and minutes before this alarm will appear and press
‖ENT‖. Maximum setting is 17 hours and 59 minutes.
13.8.4 When to Activate
After configuring the SETPOINT, the DEADBAND, and the OVERFEED alarm, the controller will
automatically move to the WHEN TO ACTIVATE screen. To set up to feed chemical on a rising ORP or
conductivity set the relay to activate above the setpoint. To set up to feed on a falling ORP or
conductivity set the relay to activate below the setpoint.
WHEN TO ACTIVATE
=====================
1 *ABOVE SETPOINT
2 *BELOW SETPOINT
Select ―1” ABOVE SETPOINT to turn on the relay when the ORP or conductivity rises above the
ORP or conductivity setpoint, or select “2” BELOW SETPOINT to turn on the relay when the ORP or
conductivity falls below the ORP or conductivity setpoint
13.8.5 By Water Meter
Relays 1, 2, 3, and 4 can be configured to operate for a specified amount of time based on a specified
amount of flow through the water meter inputs. MTR1, MTR2 or the sum of BOTH water meter inputs
can activate the relay.
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