Use Of Secondary Performance Specifications; Theory Of Operation; Calibrator Overview; Digital Section Overview - Fluke Calibration 5730A Service Manual

5730A
Service Manual
Relative accuracy specifications are provided for enhanced accuracy
applications. These specifications apply when range constants are adjusted (see
"Range Adjustment" in Chapter 7 of the Operators Manual). To calculate
absolute accuracy, combine the uncertainties of the external standards and
techniques with relative accuracy.
The accuracy specifications can be used to determine the component of
instrumental uncertainty for a particular measurement condition at time of use.
When the Calibrator is correctly calibrated, the specifications may be applied to
subsequent uncertainty analyses as a Type B evaluation of measurement
uncertainty. This is estimated as a normal distribution with a coverage factor of
K=2.58. Instrumental measurement uncertainty is one of many contributors that
must be considered in a thorough uncertainty analysis.

Use of Secondary Performance Specifications

Secondary performance specifications and operating characteristics are included
in the absolute specifications. They are provided for special calibration
requirements such as stability or linearity tests.

Theory of Operation

Calibrator Overview

Figures 1 and 2 comprise the block diagram of the Calibrator. These figures are
in the Analog Section Overview and the Digital Section Overview.
The Calibrator is configured internally as an automated calibration system with
process controls and consistent procedures. Internal microprocessors control all
functions and monitor performance, using a switching matrix to route signals
between modules. Complete automatic internal diagnostics, both analog and
digital, confirm operational integrity.

Digital Section Overview

The unguarded Digital Section contains the CPU assembly (A20), Digital
Motherboard (A4), Front Panel assembly (A2), and the unguarded portion of the
Rear Panel assembly (A21). Figure 1 is a block diagram of the digital section of
the Calibrator.
The CPU assembly uses a soft-core microprocessor contained within an FPGA
(Field-Programmable Gate Array), running the μCLinux operating system. It
controls local and remote interfaces, as well as serial communications over a
fiber-optic link to the crossing portion of the Regulator/Guard Crossing assembly
(A17). The guard crossing controls the guarded analog circuitry. This board also
includes an MSP430 microcontroller that does the keyboard scanning and soft-
power control functions.
The Front Panel assembly provides user control of the Calibrator and includes
subassemblies. The 33-key Keypad assembly (A2) contains the knob encoder,
beeper, and USB port. It attaches to the color display, backlight, touch panel, and
terminal ring LEDs. The assembly connects to the Digital Motherboard (A4) via
an Airmax connector.
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