Emerson Rosemount 644h Manuál stáhnout pdf (Strana 30)

4-2

Rosemount Inc

TABLE 4-2. Hardware diagnostic messages

Symptom

Potential

Source

Corrective Action

Transmitter

Does Not

Communicate

with HART

Communicator

Loop Wiring

• Check the revision level of the transmitter device descriptors

(DDs). The communicator should report Dev v5, DD v2.

• Check for a minimum of 250 ohms resistance between the

power supply and HART-based communicator connection.

• Check for adequate voltage to the transmitter. If a HART-

based communicator is connected and 250 ohms resistance

is in the loop, the transmitter requires a minimum of 12.0 V at

theterminalstooperate(overentire3.75to23mA

operating range).

• Check for intermittent shorts, open circuits, and multiple

grounds.

• Specify the transmitter by tag number. For certain non-

standard transmitter installations, specify the transmitter tag

number to initiate communications.

High Output

Sensor Input

Failure or

Connection

• Connect a HART-based communicator and enter the

Transmitter test mode to isolate a sensor failure.

• Check for a sensor open or short circuit.

• Check the process variable to see if it is out of range.

Loop Wiring

• Check for dirty or defective terminals, interconnecting pins,

or receptacles.

Power

Supply

• Check the output voltage of the power supply at the

transmitter terminals. It should be 12.0 to 42.4 V dc (over

entire 3.75 to 23 mA operating range).

Electronics

Module

• Connect a HART-based communicator and enter the

transmitter status mode to isolate module failure.

• Connect a HART-based communicator and check the sensor

limits to ensure calibration adjustments are within the sensor

range.

Erratic Output

Loop Wiring

• Check for adequate voltage to the transmitter. It should be

12.0 to 42.4 V dc at the transmitter terminals (over entire

3.75 to 23 mA operating range).

• Check for intermittent shorts, open circuits, and multiple

grounds.

• Connect a HART-based communicator and enter the Loop

test mode to generate signals of 4 mA, 20 mA, and user-

selected values.

Electronics

Module

• Connect a HART-based communicator and enter the

Transmitter test mode to isolate module failure.

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