Fluke 2625A, 2635A AC Signal Crosstalk into a Temperature Channel, Type Worst case Typical

Introduction and Specifications 1

Specifications

Table 1-3. 2620A/2625A Specifications (cont)

AC Signal Crosstalk into an Ohms Channel

AC Frequency = 50, 60 Hz, ±0.1%

	OHMS Error Ratio =			⎡	Ohmss (error)		⎤
				⎢			⎥
				⎣ VAC rms (crosstalk) ⎦
Range	Ratio (worst case)						Ratio (typical)
300.00Ω	3.3 x 10	-5	⎡	Ohms		⎤	No Effect
			⎢			⎥
			⎣ VAC rms ⎦
3.000 kΩ	2.4 x 10	-6	⎡	kOhms		⎤	6.7 x 10	-7	⎡	kOhms ⎤
			⎢			⎥			⎢		⎥
			⎣ VAC rms ⎦						⎣ VAC rms ⎦
30.000 kΩ	3.1 x 10	-4	⎡	kOhms		⎤	8.4 x 10	-5	⎡	kOhms ⎤
			⎢			⎥			⎢		⎥
			⎣ VAC rms ⎦						⎣ VAC rms ⎦
300.00 kΩ	5.6 x 10	-3	⎡	kOhms		⎤	3.7 x 10	-3	⎡	kOhms ⎤
			⎢			⎥			⎢		⎥
			⎣ VAC rms ⎦						⎣ VAC rms ⎦
3.0000 MΩ	3.8 x 10	-4	⎡	MOhms ⎤			3.8 x 10	-5	⎡	MOhms ⎤
			⎢			⎥			⎢		⎥
			⎣ VAC rms ⎦						⎣ VAC rms ⎦
10.000 MΩ	1.4 x 10	-3	⎡	MOhms ⎤			4.3 x 10	-4	⎡	MOhms ⎤
			⎢			⎥			⎢		⎥
			⎣ VAC rms ⎦						⎣ VAC rms ⎦

For example, to find the typical effect of a 60 Hz, 100V ac signal on another channel for the 30 kΩ range, you would calculate: 100 X 8.4 X 10-5= 0.008 kΩ.

AC Signal Crosstalk into a Temperature Channel

Frequency = 50, 60 Hz

Temperature Error Ratio =	⎡	°C (error)	⎤
	⎢		⎥
	⎣ VAC rms (crosstalk) ⎦

Type	Worst case					Typical
		-3	⎡	°C	⎤		-4	⎡	°C	⎤
Types J, K, E, T, N:	2.7 x 10		⎢		⎥	5.0 x 10		⎢		⎥
			⎣ VAC rms ⎦					⎣ VAC rms ⎦
Types R, S, B, C:	1.1 x 10	-2	⎡	°C	⎤	2.0 x 10	-3	⎡	°C	⎤
			⎢		⎥			⎢		⎥
			⎣ VAC rms ⎦					⎣ VAC rms ⎦
Type PT (RTD):	8.6 x 10	-5	⎡	°C	⎤	No Effect
			⎢		⎥
			⎣ VAC rms ⎦

AC Signal Crosstalk into a Frequency Channel

Frequency measurements are unaffected by crosstalk as long as the voltage-frequency product is kept below the following limits:

	Worst Case	Typical
V x Hz Product Limit	3.7 x 104 (V x Hz)	1.0 x 106 (V x Hz)

1These valkues assu;me no more than 1000 pF of capacitance between either end of the resistor (HI and LOW) and earth groung.

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