Emerson Oxymitter 5000, Instruction Manual

Page: 73 / 226

Instruction Manual
IM-106-350, Rev 2.2
July 2008
4-5
Oxymitter 5000
Calibration Handshake Signal
If using an optional IMPS 4000 or SPS 4001B, the logic I/O must be
configured for calibration handshaking. Of the ten modes in Table 4-1, only
modes 8 and 9 are configured for calibration handshaking. For an Oxymitter
5000 with an IMPS 4000 or an SPS 4001B, the factory sets the default to
mode 8. In this mode, the logic I/O will be used to communicate between the
Oxymitter 5000 and the sequencer and to signal the sequencer when a
CALIBRATION RECOMMENDED indication occurs.
Recommended
Configuration
Fieldbus Signal Upon Critical Alarm
Emerson Process Management recommends that the factory default be
utilized. When a critical alarm occurs which causes the O
2
reading to become
unstable or unreliable, the Oxymitter will flag the O
2
reading. All further O
2
readings will be flagged as Out Of Service until the problem has been
corrected.
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.
Calibration
Emerson Process Management 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 4001B or IMPS 4000, consider wiring some or all
associated alarm contacts.
1. CALIBRATION INITIATE. Contact from the control room to an SPS
4001B 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 via fieldbus, or from the keypad on the
Oxymitter 5000.
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 4001B 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 4001B or
IMPS 4000 to the control room for notification that the calibration
procedure failed. Grouped with this alarm is an output from a pressure
switch which indicates when the calibration gas bottles are empty.