PART ONE - INTRODUCTION
SECTION 1 - GENERAL INFORMATION
Model P53 pH/ORP Analyzer (universal-mount 1/2 DIN)
Rev. 6-501
16
Relays
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1.2 Modular Construction
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 value
(ACTIVE OUTPUTS).
The analyzer may have up to four electromechanical relays,
all with SPDT contacts. Each relay can be set to function as
a CONTROL, ALARM, STATUS or TIMER relay. CONTROL
and ALARM relays can be assigned to be driven by the
measured pH (or ORP) or measured temperature.
NOTE:
Since TIMER and STATUS relays are driven by
other criteria, the parameter assigned to these re-
lays is not relevant and, therefore, disregarded.
Refer to PART THREE, Section 4.5 for relay setup details.
NOTE:
When a relay is set to function as a STATUS relay,
it is no longer configurable. Instead, it becomes a
dedicated system diagnostic-only alarm relay that
automatically energizes when the “WARNING
CHECK STATUS” message flashes on the
MEASURE screen. This occurs when the analyzer
detects a “fail” diagnostic condition. See PART
THREE, Section 6.1 for more details.
Except for STATUS relays, during calibration the relay
on/off states are affected in the same way as the analog
outputs by the “(HOLD/XFER/ACTIVE) OUTPUTS” screen
selection. These relays are also held at their present on/off
states, transferred to desired preset on/off states, or remain
active to respond to measured values.
The modular construction of the analyzer simplifies field
servicing and provides electrical safety. The front door/
keypad assembly uses voltages no greater than 24 VDC,
and is completely safe to handle.
Opening the analyzer door accesses terminals inside the
enclosure for electrical connections. Line power must be
connected to specifically designated terminals on TB3.
