Fluke NetDAQ 2640A, Service Manual

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Introduction and Specification
Introduction
1
1-3
Introduction 1-1.
This Service Manual supports performance testing, calibration, servicing, and
maintenance of the 2640A NetDAQ
™
and 2645A NetDAQ networked data acquisition
units (Figure 1-1). NetDAQ networked data acquisition units are 20-channel front ends
that operate in conjunction with a host computer to form a networked data acquisition
system. The host computer and instruments are interconnected using an Ethernet
network, and the host computer runs the NetDAQ Logger for Windows application to
provide an operating environment for the instruments, including testing and calibration.
The 2640A and 2645A networked data acquisition units are identical in operation and
appearance, and vary only in emphasis: The 2640A emphasizes precision and supports
up to 100 measurements per second, with 5 ½ digits of resolution, .02% accuracy, and
150-volt common mode voltage (300 volts on channels 1 and 11), while the 2645A
emphasizes increased measurement speed supporting up to 1000 measurements per
second, with 4 ½ digits of resolution, .04% accuracy, and 50-volt common mode voltage.
Refer to Table 1-1 for a summary of instrument specifications. For complete instrument
specifications, see “Specifications” later in this chapter.
The instruments measure dc volts, ac volts, ohms, temperature, frequency, and dc
current. Temperature measurements use thermocouples or resistance-temperature
detectors (RTDs). Refer to Table 1-2 for a summary of instrument measurement
capabilities. In addition, there are eight digital input/output lines, one totalizing input,
one external trigger input, one trigger output, and one master alarm output. The
instruments can be ac or dc powered. An RS-232 serial port is supplied for servicing and
maintenance procedures.
The term "instrument" is used in this manual to refer to both units. The model number
(2640A or 2645A) is used when discussing characteristics unique to one instrument.
Instrument assemblies are identical except for the A3 Analog/Digital Converter printed
circuit assembly (pca), which is specific to the 2640A (mechanical switching for
measurement signals) and 2645A (solid-state switching for measurement signals).
The instrument is designed for bench-top, field service, and system applications. A dual
vacuum-fluorescent display uses combinations of alphanumeric characters and
descriptive annunciators to provide prompting and measurement information during
setup and operation modes. Some features provided by the instrument are listed in Table
1-3. For additional information regarding instrument features and capabilities, refer to
the NetDAQ Users Manual (PN 942623).
NetDAQ
NETWORKED DATA ACQUISITION UNIT
COMM
DIO MON
ENTER
CAL
ENABLE
REM SCAN
MON
V DC
CH
Figure 1-1. 2640A/2645A NetDAQ Networked Data Acquisition Units