Emerson 644 manual Temperature Effects Examples

Rosemount 644

Reference Manual

00809-0400-4728, Rev AA June 2011

Table A-2. Ambient Temperature Effect

			Temperature Effects per 1.0 °C
		Input Range	(1.8 °F) Change in Ambient
Sensor Options	Sensor Reference	(°C)	Temperature(1)	Range	D/A Effect(2)
Other Input Types
Millivolt Input		-10 to 100 mV	0.0005 mV	Entire Sensor Input Range	0.001%	of span
2-, 3-, 4-wire Ohm		0 to 2000 Ω	0.0084 Ω	Entire Sensor Input Range	0.001% of span

(1)Change in ambient is with reference to the calibration temperature of the transmitter 68 °F (20 °C) from factory.

(2)Does not apply to FOUNDATION fieldbus.

Transmitters can be installed in locations where the ambient temperature is between –40 and 85 °C (–40 and 185 °F). In order to maintain excellent accuracy performance, each transmitter is individually characterized over this ambient temperature range at the factory.

Temperature Effects Examples

When using a Pt 100 (α = 0.00385) sensor input at 30 °C span at 30 °C ambient temperature:

•Digital Temperature Effects: 0.003 °C x (30 - 20) = 0.03 °C

•D/A Effects: No D/A effects apply

•Worst Case Error: Digital + Digital Temperature Effects = 0.15 °C + 0.03 °C = 0.18 °C

• Total Probable Error: 0.152 + 0.032 = 0.153°C

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