Fluke 2635A user manual AC Signal Cross Talk into a Frequency Channel

Appendices

Crosstalk Considerations B

10.000 Me	1.4 × 10	-3	⎡	MOhms ⎤		4.3 × 10	-4	⎡	MOhms ⎤
			⎢		⎥			⎢		⎥
			⎣	Vrms ⎦				⎣	Vrms ⎦

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.

1These values assume no more than 1000 pf of capacitance between either end of the resistor (HI and LOW ) and

earth ground.

AC Signal Cross Talk into a Frequency Channel

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

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

AC Signal Crosstalk into a Temperature Channel

Frequency = 50, 60 Hz

⎡ ° C(error)

TEMPERATURE Error Ratio = ⎢

⎣VACrms(crosstalk )

⎤

⎥

⎦

Worst caseTypical

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

B-3