Emerson Rosemount Oxymitter 4000, Reference Manual, Page: 74 / 198

3.5.2 Calibration handshake signal
If using an optional Rosemount IMPS 4000 or SPS 4001B, you must configure the logic I/O
for calibration handshaking.
Of the 10 modes in Table 2-9 , only modes 8 and 9 are configured for calibration
handshaking. For a transmitter with a Rosemount IMPS 4000 or an SPS 4001B, the factory
sets the default to mode 8. In this mode, the logic I/O is used to communicate between
the transmitter and the sequencer.
3.6 Recommended configuration
3.6.1 4-20 mA signal on critical alarm
Emerson recommends using the factory default. The 4-20 mA signal will go to the 3.5 mA
level upon any critical alarm, which will cause the O
2
reading to be unstable.
The customer can also select 21.6 mA as the failure setting if normal operations cause the
O
2
readings to go below the zero % O
2
(3.5 mA) level. If using the O
2
measurement as part
of an automatic control loop, place the loop into manual upon this failure event or take
other appropriate action.
3.6.2 Calibration
Emerson recommends using 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 lives. 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 using the Rosemount
™
SPS 4001B
or IMPS 4000, consider wiring some or all associated alarm contacts.
1. CALIBRATION INITIATE: Contact from the control room to a Rosemount SPS4001B
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 Solutions software, or
from the keypad on the Rosemount 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 Rosemount SPS 4001B or IMPS 4000. If the O
2
signal is
being used in an automatic control loop, use this contact to place the control loop
into Manual during calibration.
3. CALIBRATION FAILED: One contact per probe from a Rosemount SPS 4001B or IMPS
4000 to the control room for notification that the calibration procedure has failed. A
pressure switch, which indicates when the calibration gas bottles are empty, is
grouped with this alarm.
4. 4-20 mA SIGNAL DURING CALIBRATION: You can configure the 4-20 mA signal to
respond normally during any calibration or to hold the last O
2
value upon the
Configure transmitter with membrane keypad Reference Manual
October 2019 00809-0100-4340
74 Emerson.com/Rosemount