PART THREE - OPERATION
SECTION 4 - CONFIGURING THE ANALYZER
Accu4™ Low-range Turbidimeter System
Rev. 2-300
44
4.4 Configuring Relays
(A, B, C, and D)
SET FUNCTION Mode
(alarm, control, or status)
The analyzer is equipped with four electromechanical relays
(A, B, C, and D). Each relay can be set to function as a
CONTROL, ALARM, or STATUS relay. For details on each
relay function, see subsection “SET FUNCTION Mode.”
During calibration, CONTROL and ALARM (not STATUS)
relays can be held at their present on/off states, transferred
to preset on/off states, or remain active. During normal
measurement operation, CONTROL and ALARM relays can
be:
•
Held at their present on/off states for up to 30 minutes
by using the “CHECK CAL/HOLD” function in the TEST/
MAINT menu.
•
Held at their present on/off states indefinitely by locally
or remotely connecting both TTL input terminals on
TB1.
If a TEST/MAINT hold is applied in addition to a TTL hold,
both “holds” must be removed before CONTROL and
ALARM relays return to active status. If the relays are set to
“XFER” or “ACTIVE” during a calibration, they remain in that
state until after calibration regardless of the TTL input
status.
These instructions configure Relay A. Configure other
relays in the same way using their respective menu
screens.
Each relay can be selected to function as a:
•
ALARM
relay (with separate high and low alarm points
and deadbands) that operates in response to the
measured turbidity.
•
CONTROL
relay (with phasing, setpoint, deadband,
and overfeed timer) that operates in response to the
measured turbidity.
•
STATUS
relay that operates only in response to
selected system diagnostic conditions. It can be
configured for:
FAIL mode -- sets STATUS relay to activate when
there is a FAIL condition (analyzer, light source or
detector) or a sensor CHAMBER UNKNOWN
condition.
