Fisher 244ER, 244EH manual Ambient Temperature Effect

= 0.97°C

Rosemount Models 244EH and 244ER PC-Programmable Temperature Transmitters

Ambient Temperature Effect	Transmitters can be installed in locations where the ambient
	temperature is between –40 and 85 °C (–40 and 185 °F). At the factory,
	each transmitter is individually characterized over this ambient
	temperate range. This special manufacturing technique is
	accomplished through hot and cold temperature profiling with
	individual adjustment factors programmed into each transmitter. The
	transmitters automatically adjust for component temperature drift
	caused by changing environmental conditions.
TABLE A-3. Models 244E Ambient Temperature Effects per 1 °C (1.8 °F)
Sensor Options(1)	Fixed Value	% of reading			% of Span
		(if reading > 0)	(if reading is < 0)
2-, 3-, 4-wire RTDs
PT 100 (α = 0.00385)	0.003 °C	—		—	+0.001% of span
Pt 100 (α = 0.003916)	0.003 °C	—		—	0.001% of span
Pt 200	0.004 °C	—		—	0.001% of span
Pt 500	0.003 °C	—		—	0.001% of span
Pt 1000	0.003 °C	—		—	0.001% of span
Ni 120	0.003 °C	—		—	0.001% of span
Cu 10	0.03 °C	—		—	0.001% of span
Thermocouples
Type B (100 °C ≤ reading < 300 °C)	0.064 °C	–0.011		—	0.001% of span
(300 °C ≤ reading < 1000 °C)	0.040 °C	–0.025		—	0.001% of span
(reading ≥ 1000 °C)	0.014 °C	—		—	0.001% of span
Type E	0.005 °C	–0.00043		–0.0043	0.001% of span
Type J, K, DIN L	0.006 °C	–0.00054		–0.0025	0.001% of span
Type N	0.007 °C	–0.00036		—	0.001% of span
Type R, S (reading < 200 °C)	0.023 °C	–0.0036		—	0.001% of span
(reading ≥ 200 °C)	0.016 °C	—		—	0.001% of span
Type T, DIN U	0.007 °C	—		–0.043	0.001% of span
Type W5Re/W26Re	0.023 °C	–0.0036		—	0.001% of span
	0.016°C			—
Millivolt Input	0.0005 mV	—		—	0.001% of span
2-, 3-, 4-wire Ohm	0.0084 Ω	—		—	0.001% of span

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

When using a Type J thermocouple with a –50 °C to 600 °C temperature range at an ambient temperature of 60 °C and a reading of –25 °C, the ambient temperature effect according to °C is: [fixed value

(a)+ (% of reading (b) 3 reading) + (% of span (c) 3 span)] = [0.006 + (– 0.000025 3 (–25)) + (0.00001 3 650)] = 0.013 °C per °C. With the ambient temperature 40 °C above reference condition temperature, the total ambient temperature effect is: 40 3 0.013 = 0.52 °C.

When using a Type J thermocouple with a –50 °C to 600 °C temperature range at an ambient temperature of 60 °C and a reading of 525 °C, the ambient temperature effect according to °C is:[fixed value

(a)+ (% of reading (b) 3 reading) + (% of span (c) 3 span)] = [0.006 + (0.0000054 3 525) + (0.00001 3 650)] = 0.015 °C per °C. With the ambient temperature 40 °C above reference condition temperature, the total ambient temperature effect is: 40 3 0.015 = 0.6 °C.

The worst case error would be: Reference Accuracy + CJC Accuracy +

Temp Effects = 0.65 °C + 0.5 °C + 0.52 °C = 1.67 °C. Total Probable

Error: 0.652 + 0.52 + 0.522

A-4