Calibrating The Board; Introduction; Calibration Theory - Measurement Computing PCI-DAS6013 User Manual

Calibrating the Board

Introduction

You should calibrate the board (using the InstaCal utility) after the board has fully
warmed up. The recommended warm-up time is 15 minutes. For best results, calibrate
the board immediately before making critical measurements. The high resolution analog
components on the board are somewhat sensitive to temperature. Pre-measurement
calibration ensures that your board is operating at optimum calibration values.

Calibration theory

Analog inputs are calibrated for offset and gain. Offset calibration for the analog inputs
is performed directly on the input amplifier, with coarse and fine trim DACs acting on
the amplifier.
For input gain calibration, a precision calibration reference is used with coarse and fine
trim DACs acting on the ADC (see Figure
Analog In
Trim DAC
Coarse
Trim DAC
Fine
Trim DAC
Coarse
Trim DAC
Fine
Trim DAC
Coarse
Trim DAC
Fine
Figure 5-1. Analog Input Calibration - Basic Elements
5-1).
PGIA
Pre-Gain
Offset
Post-Gain
Offset
Gain
Adjust
5-1
Chapter 5
A/D