Emerson Process Management IM-106-910Xi Electrical Noise, Electrostatic Discharge

Instruction Manual

IM-106-910Xi, Original Issue November 2010

Xi Advanced Electronics

Electrical Noise

The Xi has been designed to operate in the type of environment normally found in a boiler room or control room. Noise suppression circuits are employed on all field terminations and main inputs. When fault finding, evaluate the electrical noise being generated in the immediate circuitry of a faulty system. Ensure all cable shields are connected to earth.

Electrostatic Discharge

ALARM INDICATIONS

Electrostatic discharge can damage the ICs used in the electronics. Before removing or handling the circuit boards, ensure you are at ground potential.

The first indication of a problem at the O2 measuring system usually comes from the operators running the process. Critical alarms that render the O2 measurement unusable will force the 4-20 mA analog output signal represent- ing O2 to go to a default condition, as follows:

4-20 mA Signal
Alarm Level	Transmitter Condition
0 mA	Transmitter unpowered, or completely failed
3.5 mA	Critical Alarm - transmitter reading unusable (factory default)
3.8 mA	Reading Under Range
	(Example - user sets range to 2-10%. Current reading is 1.9%)
4 to 20 mA	Normal Operation
20.5 mA	Reading Over Range (Example - range is 0-10%. Current reading is 12%)
>21 mA	Critical Alarm - transmitter reading is unusable (user can choose this alarm
	level instead of the factory default level of 3.5 to 3.6 mA)

IDENTIFYING AND CORRECTING FAULT INDICATIONS

NOTE

To ensure correct operation you should make sure that the Digital Control System is configured to interpret these signal levels correctly.

Once an alarm condition is identified, the Xi offers a number of diagnostics to interpret the specific alarm.

Alarm indications are available via the Xi or the 375/475 Field Communicator and Rosemount Analytical's Asset Management software. When the error is corrected and/or power is cycled, the diagnostic alarms will clear or the next error on the priority list will appear.

There are two types of alarms; recoverable and non recoverable. If an existing alarm is recoverable, the alarm-active indication will disappear when the alarm condition no longer exists. If an alarm is not recoverable, the alarm indication will continue to be displayed after the cause of the alarm condition is corrected. AC power to the Xi must be cycled to clear a non-recoverable alarm.

Alarm messages are displayed on the Xi display window when the alarm status display is accessed via the Xi menu. A listing of the alarm/fault messages and the related fault status descriptions are shown in Table 5-1.

Fault conditions that give no fault indication and that allow the probe to pass calibration are listed and discussed after Table 5-1.

5-3