PART ONE - INTRODUCTION
SECTION 1 - GENERAL INFORMATION
Accu4™ Low-range Turbidimeter System
Rev. 2-300
14
Analog Outputs
Relays
☞
The analyzer provides two isolated analog outputs (1 and
2). Each output represents the measured turbidity, and can
be set to be 0-20 mA or 4-20 mA.
Turbidity values can be entered to define endpoints at which
the minimum and maximum analog output values are desired.
During calibration, both analog outputs can be selected to:
•
Hold their present values (HOLD OUTPUTS).
•
Transfer to preset values to operate control elements by an
amount corresponding to those values (XFER OUTPUTS).
•
Remain active to respond to the measured turbidity
(ACTIVE OUTPUTS).
For complete analog output setup details, including transfer
setup, refer to Part Three, Section 4.3.
The analyzer has four electromechanical relays with SPDT
contacts. Each relay can be set to function as a CONTROL,
ALARM (dual-alarm), or STATUS relay. CONTROL and
ALARM relays operate in response to the measured turbid-
ity. STATUS relays operate only in response to selected
system diagnostic conditions.
NOTE:
Relay D is factory-set to function as a STATUS re-
lay but can be configured as a CONTROL or
ALARM relay.
When a relay is set to function as a STATUS relay, it be-
comes a dedicated system diagnostic-only alarm relay. A
STATUS relay 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.
•
WARN mode -- sets STATUS relay to activate only when
there is a sensor flow CHAMBER DIRTY condition.
•
ALL mode -- sets STATUS relay to activate when there
is any abnormal system condition (any FAIL condition,
or sensor CHAMBER DIRTY or UNKNOWN condition).
A “WARNING CHECK STATUS” message automatically
flashes on the MEASURE screen whenever the analyzer
detects any of these system diagnostic conditions:
