Rosemount Oxymitter 4000, Instruction Bulletin

Page: 62 / 127

IB-106-340
3-5
DIAGNOSTIC
ALARMS
TEST
POINTS
HEATER T/C
HEATER
O2 CELL
CALIBRATION
CALIBRATION RECOMMENDED
O2 CELL mV +
O2 CELL mv -
HEATER T/C +
HEATER T/C -
INC INC
DEC DEC
HIGH
GAS
LOW
GAS
CAL
TEST GAS +
PROCESS -
% O2
SW2
TP1
J1
TP2
TP3
RED
YEL
GRN ORG
TP4
TP5
TP6
ON
HEATER T/C
HEATER
O CELL
2
CALIBRATION
LIGHTING SEQUENCE DURING NORMAL OPERATION
1 2 3 4 1 2 3 4
HEATER T/C
HEATER
O CELL
2
CALIBRATION
LIGHTING SEQUENCE DURING WARM-UP
1 2 3 4 1 2 3 4
22220056
Figure 3-3. Startup and Normal Operation
3-3. RECOMMENDED CONFIGURATION.
a. 4-20 mA Signal Upon Critical Alarm.
Rosemount recommends that the factory default
be utilized. The 4-20 mA signal will go to the
4 mA level upon any critical alarm which will
cause the O
2
reading to be unusable. Customer
can also select 20 mA as the failure setting if
normal operations cause O
2
readings to go below
the zero % O
2
(4 mA) level.
If the O
2
measurement is being utilized as part of
an automatic control loop, the loop should be
placed into manual upon this failure event or
other appropriate action should be taken.
b. Calibration. Rosemount recommends utilizing
an autocalibration system, actuated by the
“calibration recommended” diagnostic. New O
2
cells may operate for more than a year, but older
cells may require recalibration every few weeks
as they near the end of their life. This strategy
ensures that the O
2
reading is always accurate,
and eliminates many unnecessary calibrations
based on calendar days or weeks since previous
calibration. When utilizing the SPS 4000 or the
IMPS 4000, consider wiring some or all
associated alarm contacts.
1. CALIBRATION INITIATE. Contact from
the control room to an SPS 4000 or IMPS
4000 (one per probe) provides the ability to
manually initiate a calibration at any time
from the control room. Note that calibrations
can also be initiated from a HART handheld
communicator, from Asset Management So-
lutions software, or from the keypad on the
Oxymitter 4000.
2. IN CALIBRATION. One contact per probe
provides notification to the control room that
the “calibration recommended” diagnostic has
initiated an automatic calibration through the
SPS 4000 or IMPS 4000. If the O
2
signal is
being utilized in an automatic control loop,
this contact should be utilized to place the
control loop into manual during calibration.
3. CALIBRATION FAILED. One contact per
probe from an SPS 4000 or IMPS 4000 to the
control room for notification that the calibra-
tion procedure failed. Grouped with this
alarm is an output from a pressure switch
which indicates when the calibration gas bot-
tles are empty.
4. 4-20 mA SIGNAL DURING CALIBRA-
TION. The 4-20 mA signal can be
configured to respond normally during any
calibration, or can be configured to hold the
last O
2
value upon the initiation of calibration.
Factory default is for the 4-20 mA signal to
operate normally throughout calibration.
Holding the last O
2
value may be useful if
several probes are being averaged for the
purpose of automatic control. Unless several
probes are being averaged, always place any
control loops using the O
2
signal into manual
prior to calibrating.