Omega Engineering OM-DAQ-USB-2401 manual Power Line Rejection, Optical Isolation, A/D Conversion

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4Software

4.4 Power Line Rejection

The OM-DAQ-USB-2401 Series can take readings while making use of 50/60Hz line cycle rejection. While in the line cycle rejection mode, the maximum sample rate is as follows:

50 Hz rejection: Scan Rate (SR) Range: 0.153Hz < SR <= 1Hz

60 Hz rejection: Scan Rate (SR) Range: 1Hz < SR <= 1.667Hz

OMB-DAQ-USB-2401 Series Block Diagram

Power LED

 

 

Isolation

 

Barrier

 

Power Supply

 

Isolated

Power Jack

Power Supply

Local Power

USB

 

Jack

 

USB

MCU

Controller

32Bit

Activity LED

 

 

Digital Isolators

CJC

4 Analog Inputs

+12v

Gain = x2, 1/8

+12v output Excitation voltage

CJC

4

Analog Inputs

MUX

 

 

SE/

 

PGIA

 

 

 

 

 

 

 

 

 

DI

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Gain =

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

x1,2,4,8,16

 

 

 

32,64

+12v output

 

Excitation voltage

1MΩ

 

CJC

 

4

 

Analog Inputs

 

+12v

 

+12v output

 

Excitation voltage

 

CJC

MUX

 

4

 

Analog Inputs

 

+12v output

 

Excitation voltage

 

 

MUX

 

PGA

 

24–Bit

 

1MΩ

 

 

A/D

 

 

 

 

 

 

 

 

 

 

 

 

 

Gain = x2, 1/8

 

 

 

 

 

SE/

 

PGIA

 

 

 

 

 

 

 

 

 

 

 

DI

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1MΩ 1MΩ

Figure 4-25. OM-DAQ-USB-2400 Block Diagram

4.5 Optical Isolation

Your DAQ unit is optically isolated from its host PC by up to 500 Vdc. This means that an inadvertent application of such voltage to the DAQ unit will not affect the PC. In addition to isolation, the device maintains all sensitive acquisition-related circuitry external to the PC. This physical isolation of circuitry from the PC results in less noise and more accurate measurements.

4.6 A/D Conversion

 

OM-DAQ-USB-2401 uses an extremely low-noise, 24-bit analog-to-digital (A/D)

 

converters. They provide complete high-resolution measurement solutions for

4-14

the most demanding applications.

 

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Contents OM-DAQ-USB-2401 Servicing North America OM-DAQ-USB-2400 Multiple Channel USB Data Acquisition Module OM-DAQ-USB-2400 International Usage and CE Marking 10-1List of Figures SectionExamples of Under Sampling Precautions IntroductionGeneral Description & System Components Safety Warnings and IEC SymbolsStatement on CE Marking System Components Included Items HardwarePackage Inspection OM-DAQ-USB-2401 System Components Hardware SetupUSB Hubs and Power Adaptors Power Adaptors USB-powered HubsSelf-powered Hubs Connecting Your OM-DAQ-USB-2401 Acquisition System to PC Connecting Various Hardware Setups Direct Connection to Computer USB PortsConnection to USB-powered Hub Connections to Self-Powered and USB-powered HubsConnections to Self-Powered Hub and to USB-Powered Hub OM-DAQ-USB-2401 MountingOM-DAQ-USB-2401 Wall Mounting OM-DAQ-USB-2400 SeriesOM-DAQ-USB-2401 DIN Rail Mounting OM-DAQ-USB-2401 Rail MountingSoftware Installation SoftwareGetting Started System RequirementsSoftware Setup Welcome ScreenConfirm Installation Screen DAQ Central Software Operation Main Control WindowToolbar Buttons Toolbar ButtonsMain Control Window Pull-Down Operations File MenuTools Menu 2 Device Configuration Channels TabConfiguration Parameter Settings Manual Acquisition is manually started/stopped Level Data Tab Data Displays18. Main Window Screen 23. Waveform Screen A/D Conversion Power Line RejectionOptical Isolation Analog Input Configuration Input RangesMeasurement Duration, Scan Time, and Resolution Automatic Calibration 27. Calibration/Scan Arrangement28. Thermocouple Wiring Thermocouple MeasurementsSignal Management Scan Time and ResolutionResolution Effective Number of Bits ENOB, RMS Channel Control and ExpansionUnder Sampling and Aliasing RMSSignal Examples of Under SamplingSignal Modes TriggeringNoise Reduction in Differential Mode Analog Filtering System NoiseAveraging Input and Source Impedance CrosstalkVadc = VT x Ri / Rs + Ri = RCCE Conformity OM-DAQ-USB-2401 Design for CE ConformityFerrite Core Symptoms and Solutions TroubleshootingBasic Checklist Service & Calibration Service & CalibrationSpecifications Power Supply External Power SourceThermocouple Input Range Cold JunctionThermocouple Accuracy ºC for OM-DAQ-USB-2401 TC Type Temp Typical Fast SlowApprovals and Regulatory Compliance International Usage & CE Marking10-2 10-3 10-4 WARRANTY/DISCLAIMER Temperature