Emerson MICRO MOTION 2700 Manual de Instalação descarregar pdf (Página 136)

126 Transmitter Configuration and Use: Series 1000 and 2000 Transmitters

Troubleshooting continued

10.13.3 Checking grounding

The sensor and the transmitter must be grounded. If the core processor is installed as part of the

transmitter or the sensor, it is grounded automatically. If the core processor is installed separately, it

must be grounded separately. See your sensor and transmitter installation manuals for grounding

requirements and instructions.

10.13.4 Checking for RF interference

If you are experiencing RF (radio frequency) interference on your frequency output or discrete output,

use one of the following solutions:

• Eliminate the RF source. Possible causes include a source of radio communications, or a large

transformer, pump, motor, or anything else that can generate a strong electrical or

electromagnetic field, in the vicinity of the transmitter.

• Move the transmitter.

• Use shielded cable for the frequency output.

- Terminate output cable shielding at the input device. If this is not possible, terminate the

output shielding at the cable gland or conduit fitting.

- Do not terminate shield inside the wiring compartment.

- 360° termination of shielding is not necessary.

10.13.5 Checking the HART communication loop

To check the HART communication loop:

1. Verify that the loop wires are connected as shown in the wiring diagrams in the transmitter

installation manual.

2. Remove analog loop wiring.

3. Install a 250 Ohm resistor across the primary mA terminals.

4. Check for voltage drop across the resistor (4–20 mA = 1–5 VDC). If voltage drop < 1 VDC,

add resistance to achieve voltage drop > 1 VDC.

5. Connect the Communicator directly across the resistor and attempt to communicate (poll).

If your HART network is more complex than the wiring diagrams in the transmitter installation

manual, either:

• Contact Micro Motion. See Section 10.3.

• Contact the HART Communication Foundation or refer to the HART Application Guide,

available from the HART Communication Foundation on the Internet at www.hartcomm.org.

10.14 Checking the communication device

Ensure that your communication device is compatible with your transmitter.

Communicator

The 275 HART Communicator or 375 Field Communicator is required, and must contain the

appropriate device description.

Note: For the Model 2500 transmitter, the 275 HART Communicator uses the device description for

the Model 2700 transmitter with configurable input/outputs. See Chapter 4 for more information.

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Emerson MICRO MOTION 2700 Manual de Instalação Página 136