Emerson Process Management 1500 manual 2 Sensor pins – Standard core processor

Troubleshooting

Figure 11-2Sensor pins – Standard core processor

Right pickoff

( – )

Lead length compensator	(1)	Right pickoff
		( + )
( + )

Left pickoff

( – )

Resistance temperature detector return /

Lead length compensator

(common)

Left pickoff

( + )

Resistance temperature detector	Drive
( + )
	( – )

Drive ( + )

(1)LLC for all sensors except T-Series and CMF400 I.S. For T-Series sensors, functions as composite RTD. For CMF400 I.S. sensors, functions as fixed resistor.

Figure 11-3Sensor pins – Enhanced core processor

Drive + Drive –

LLC

RTD +	RTD –
Left pickoff +	Right pickoff –
Left pickoff –	Right pickoff +

6.There should be no open circuits, i.e., no infinite resistance readings. The LPO and RPO readings should be the same or very close (± 5 ohms).

7.Using the DMM, check between each pin and the sensor case. With the DMM set to its highest range, there should be infinite resistance on each lead. If there is any resistance at all, there is a short to case. See Table 11-14 for possible causes and solutions.

Compensation

Measurement Performance

Troubleshooting

Defaults

Configuration and Use Manual 113