Making Mixed Measurements

Appendix D

Introduction

This appendix augments the discussion of ac signal effects on other channels (cross talk) found in Chapter 5 ("Making Mixed Measurements"). Effects on each measurement function are discussed below. These numbers should only be considered as references. Since cross talk can be introduced into a measurement system in many places, each setup must be considered individually.

The effect of cross talk could be much better than shown for "Typical"; in extreme cases, the effect could be worse than the "Worst Case" numbers. In general, the "Worst Case" information assumes that none of the guidelines for minimizing cross talk (Chapter 5) have been followed; the "Typical" information assumes that the guidelines have been followed where reasonable.

These numbers assume that input L (low) is tied to earth ground; refer to "Using Shielded Wiring" in Chapter 5. For dc volts and thermocouple temperature measurements, a source impedance of 1 k in series with the H (high) input is assumed (except where otherwise noted.)

Signal Cross Talk in a DC Voltage Channel

⎡VDC(error)

DCV Error Ratio (CTRR) = ⎢

⎣ VACrms

⎤

⎥

⎦

Worst case	Typical
50, 60 Hz, ±0.1%:	1.1	×	10-7	2.0	×	10-8
Other Frequencies:	3.8	×	10-6	8.6	×	10-7

For example, to find the typical effect of a 300V ac signal at 60 Hz on another channel for the 300 mV range, you would calculate: 300 × 2.0 × 10-8= 0.01 mV.

D-1

2625A, 2620A specifications

The Fluke 2625A is a sophisticated data logger designed for a wide range of industrial and laboratory applications. This versatile instrument excels in capturing and monitoring temperature and voltage measurements with precision and reliability. One of its standout features is its ability to record data from various sensors, making it ideal for environments where comprehensive data acquisition is critical.

Equipped with a large LCD display, the Fluke 2625A provides clear and user-friendly access to real-time measurement data. Its graphical interface allows users to visualize trends and monitor readings easily, which significantly enhances usability. The device supports a variety of input types and can connect to thermocouples, RTDs, and other sensors, offering great flexibility for various measurement tasks.

The Fluke 2625A employs advanced measurement technologies that ensure accuracy in data logging. With a high sampling rate, it captures fast-changing signals while maintaining data integrity. The device features a built-in memory that allows for extensive logging, accommodating long-term monitoring tasks without requiring constant oversight. Users can set it to log data at specified intervals, offering customizable solutions for different monitoring needs.

Another significant characteristic of the Fluke 2625A is its robust communication capabilities. The device supports USB and RS-232 interfaces for easy connectivity with computers and other devices, making data transfer and analysis seamless. This feature is especially beneficial for users who need to compile or analyze large sets of data quickly.

Furthermore, the Fluke 2625A is designed with durability in mind. Its rugged construction makes it suitable for challenging environments, including those with high levels of vibration, dust, or moisture. This reliability ensures that the device can withstand the rigors of fieldwork while still delivering accurate measurements.

In summary, the Fluke 2625A is a powerful data logger that combines versatility, accuracy, and reliability. Its user-friendly interface, advanced measurement technologies, and robust design make it an essential tool for professionals in various industries, from manufacturing and HVAC to research and development. Whether monitoring temperature changes in a laboratory or assessing voltage levels in an industrial setting, the Fluke 2625A stands out as a trusted solution for effective data logging and analysis.

Fluke 2620A, 2625A user manual Making Mixed Measurements, Signal Cross Talk in a DC Voltage Channel

Models: 2625A 2620A