Emerson Process Management 2400S manual 3 Accessing the feedthrough pins

Troubleshooting

Figure 11-3Accessing the feedthrough pins

Transmitter
(side view)	Sensor cable for
	feedthrough connection

Snap clip (assembled)	Feedthrough connector
Pull tab to remove	Feedthrough pins

6.Using a digital multimeter (DMM), check the sensor internal resistances for each flowmeter circuit. Table 11-8defines the flowmeter circuits and the resistance range for each. Refer to Figure 11-4to identify the feedthrough pins. For each circuit, place the DMM leads on the pin pairs and record the values.

Note: In order to access all feedthrough pins, you may need to remove the clamp and rotate the transmitter to a different position.

In this test:

•There should be no open circuits, i.e., no infinite resistance readings.

•Nominal resistance values vary 40% per 100 °C. However, confirming an open or shorted circuit is more important than any slight deviation from the resistance values shown here.

•The LPO and RPO circuit readings should be the same or very close (± 10%).

•The readings across pin pairs should be steady.

•Actual resistance values depend on the sensor model and date of manufacture. Contact Micro Motion for more detailed data.

If a problem appears, or if any resistance is out of range, contact Micro Motion (see Section 11.3).

Table 11-8Nominal resistance ranges for flowmeter circuits

Circuit	Pin pairs	Nominal resistance range(1)
Drive	Drive + and –	8–1500 Ω
Left pickoff	Left pickoff + and –	16–1000 Ω
Right pickoff	Right pickoff + and –	16–1000 Ω

Compensation

Measurement Performance

Troubleshooting

Defaults

Configuration and Use Manual 127