Hach sc1000 - Manual (Page 89)

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Advanced Operations
6.3.3 Relay menu
Note: This menu appears only if a relay card is installed in the sc1000 controller.
The relay menu content for a relay card depends on the selected working mode. There
are several relay card working modes:
ALARM
Relay controls if a process value is between two limits.
FEEDER CONTROL
Relay indicates if a process value exceeds or falls below a set point.
2 POINT CONTROL
Relay toggles if a process value reaches an upper or lower limit.
WARNING
Relay indicates warning and error conditions in probes.
PWM CONTROL
Relay uses a Pulse-Width-Modulation control depending on a process value.
FREQ. CONTROL
Relay switches in a frequency depending on a process value.
TIMER
Relay switches at certain times independently of any process value.
SYSTEM ERROR
Relay indicates if any probe in the system has an internal error, warning or is missing.
6.3.3.1 General relay settings (available in all relay working modes)
SYSTEM SETUP
RELAY
RELAY INT/EXT
Select RELAY card 1, 2, 3 or 4
SELECT SOURCE
Default value: No source
Select a probe or create a formula which delivers the process value that is processed by the
relay card.
SET PARAMETER
Default value: No parameter
Select a parameter of the selected source.
Displayed parameter depend on the connected sc probe, for example oxygen concentration or
temperature.
DATA VIEW
Default value: INPUT CONFIG
Sets the value which is shown as the measured value in the display module and logged into the
data logger.
RELAY CONTACT Displays and logs the status of the relay contact (ON or OFF).
INPUT CONFIG
Process value read from the selected source after it has been processed by the internal formula
parser (if prompted).
SET FUNCTION
Default value: ALARM
Sets the relay card working mode.
ALARM
Operates relays in response to the measured parameter. Contains separate High and Low Alarm
points, deadbands, and ON/OFF delay.