Hach sc100 User Manual page 37

4.9 System Setup Menu (continued)
RELAY SETUP
Select Relay A, B, or C
SELECT SOURCE
. Select from none, a connected sensor, or the real time clock (RTC)
SET PARAMETER
Press to select from the displayed parameters.
ENTER
SET FUNCTION
Source set to sensor
Alarm: Operates relays in response to the measured parameter. Contains separate High and Low Alarm points,
deadbands, and ON/OFF delay.
Feeder Control: Operates in response to the measured parameter. Can be set for phasing, setpoint, deadband, overfeed
timer, and ON/OFF delay.
Event Control: Controls a cleaning system (or equivalent) on a timed basis.
Warning: Activated when the analyzer detects a sensor warning.
PMW Control: Allows the relay to provide a duty cycled output.
Freq Control: Allows the relay to cycle at a frequency between the minimum pulse per minute and maximum pulse per
minute.
Source set to RTC
Timer:
Sets the timer for a cleaning system (or equivalent). Controls the output hold, interval, duration, and off delay.
SET TRANSFER
Sets the relay to Energize or De-energize (user-selectable). Normally, each control or alarm relay is active,
responding to the measured value of its assigned parameter. During calibration, however, the relay can be
transferred to a preset on/off state to suit the application requirements. Select Energize or De-energize and
press ENTER.
FAILSAFE
Allows the user to create a state where the normal condition is energized. The relay is de-energized when an
error condition is experienced. Select YES (Energized) or NO (De-energized) and press ENTER. YES sets
the relay normal condition to energized resulting in the relay becoming de-energized when an error condition
is experienced.
ACTIVATION
Function set to ALARM
LOW ALARM—Sets the value where the relay will turn on in response to decreasing measured value. For example, if
the low alarm is set for 1.0 and the measured value drops to 0.9, the relay will be activated.
HIGH ALARM—Sets the value where the relay will turn on in response to increasing measured value. For example, if
the high alarm is set for 1.0 and the measured value increases to 1.1, the relay will be activated.
LOW DEADBAND—Sets the range where the relay remains on after the measured value increases above the low
alarm value. Default is 5% of the range. For example, if the low alarm is set for 1.0 and the low deadband is set for 0.5,
then the relay remains on between 1.0 and 1.5.
HIGH DEADBAND—Sets the range where the relay remains on after the measured value decreases below the high
alarm value. Default is 5% of the range. For example, if the high alarm is set for 4.0 and the high deadband is set for 0.5,
then the relay remains on between 3.5 and 4.0.
OFF DELAY—Sets a time (0–300 seconds) to delay the relay from normally turning off.
ON DELAY—Sets a time (0–300 seconds) to delay the relay from normally turning on.
LOW ALARM—Sets the value where the relay will turn on in response to decreasing measured value. For example, if
the low alarm is set for 1.0 and the measured value drops to 0.9, the relay will be activated.
Operation
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