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Product Specific
Why Isolate Analog Signals?  
Application Note AN116 five very real, and very different reasons to isolate every one of your analog signals.
»More about Why Isolate Analog Signals? ...

RTD Tutorial  
In three pages, this newsletter provides nearly everything you'd ever want to know about resistance temperature detectors, or RTDs. From the physics of temperature effects on electron flow to mathematical models and equivalent circuit behaviors... you will be happy to learn that someone else considers all these details in signal conditioning design!
»More about RTD Tutorial ...

Data Acquisition System - Wish List  
Here's your opportunity to specify what you want in a data acquisition system
»More about Data Acquisition System - Wish List ...

Configurable 5B module?  
The world's first configurable "5B" is now here … Dataforth engineering has created the configurable SCM5B48-01 Accelerometer Module.
»More about Configurable 5B module? ...

5B for Piezo-electric Accelerometers  
Dataforth now has a new 5B modular signal conditioner designed specifically to interface to IEPE type accelerometers! The SCM5B48 signal conditioner provides DIP switches (yes, DIP switches in a potted 5B) for configuration
»More about 5B for Piezo-electric Accelerometers ...

Miniature electronics... 8B modules  
Tiny microprocessor chips containing millions of MOS type (metal oxide silicon) “transistor” cells now permeate all aspects of our daily lives … Dataforth's 8B module has reduced earlier designs to 20% the size at a lower cost yet still provide "Instrument Class" performance.
»More about Miniature electronics... 8B modules ...

Signal Conditioner with Power Supply  
Think about any hand-held multimeter and you will agree how important input protection and isolation are to most measurement applications! ...
»More about Signal Conditioner with Power Supply ...

Easy Recalibration Procedure  
How would you like a simple, single-page instruction to recalibrate your signal conditioners? How would you like to be able to recalibrate the zero point and then recalibrate the span without going back to readjust the zero and then again adjust the span, and then the zero ... you get the picture!
»More about Easy Recalibration Procedure ...

DIN or 5B/7B Option  
You have a choice. More and more we hear how DIN is IN! We see how manufacturers have packaged many of their new products in DIN mount enclosures ...
»More about DIN or 5B/7B Option ...

5B or 7B  
Comparison of 5B and 7B signal conditioning modules: If you're familiar with 5B signal conditioners, you might not be familiar with 7Bs, or if you've used 7Bs you may not know about 5Bs ...
»More about 5B or 7B ...

Isolated I/O to Serial Data  
Over 75% of the industrialized world still uses RS-232 or RS-485 serial data communications to acquire process variable information and to control associated electrical / electronic systems...
»More about Isolated I/O to Serial Data ...

Sensor Specific
Confident Strain-Gage Measurements  
For load-cells, torque measurements, or for almost any bridge completion circuit, Dataforth probably has the "strain gage" signal conditioner you need! We have full, half and quarter bridge signal conditioners. Analog voltage or current output as well as RS-232 or RS-485 output conditioners ...
»More about Confident Strain-Gage Measurements ...

Thermocouples  
Our application notes "Introduction to Thermocouples" and "Using Thermocouples", we explore the history of thermocouple technology and look at some modern day specs ...
»More about Thermocouples ...

RTD Tutorial  
In three pages, this newsletter provides nearly everything you'd ever want to know about resistance temperature detectors, or RTDs. From the physics of temperature effects on electron flow to mathematical models and equivalent circuit behaviors...
»More about RTD Tutorial ...

Confident Strain Gage Measurements...  
Dataforth probably has the strain gage signal conditioner you need! We have full, half and quarter bridge signal conditioners...
»More about Confident Strain Gage Measurements... ...

Tutorial
SCM and Alias Filters  
In general, most SCM have built-in Low Pass (LP) filters as part of their design. In addition to the obvious benefits of such filtering, there is the very important subtle benefit. Namely, SCM with high quality multi-pole LP filters can be viewed inherently as having anti-alias filtering capabilities.
»More about SCM and Alias Filters ...

Low Pass Filter Rise Time vs Bandwidth  
This app note captures much of the design considerations used to create industrial, instrument class signal conditioners. Although this application note is a little heavy on the math, page 6 presents a few illustrations showing the excellent results of such detailed engineering effort.
»More about Low Pass Filter Rise Time vs Bandwidth ...

Strain Gage Signal Conditioners  
This app note will use the bridge circuit to measure strain gages.
»More about Strain Gage Signal Conditioners ...

Basic Bridge Circuits  
This app note explores many of the mathematical relationships among the various topologies of bridge circuits and provides you with enough background information to prepare for the next Dataforth Application Note on Strain Gage measurements.
»More about Basic Bridge Circuits ...

Six Sigma - What? Why? How?  
Product variation and defects undercut customer loyalty as well as company profits. Six Sigma is a rigorous, disciplined, data-driven methodology that was developed to enhance product quality and company profitability by improving manufacturing and business processes.
»More about Six Sigma - What? Why? How? ...

Windmill Applications  
This white paper recommends what I/O typically needs to be monitored and what controllers are best suited on a windmill in order to provide the safest and longest trouble-free operation. Moreover, due to the special environmental nature of the application, what signal conditioning hardware should be used to assure successful operation.
»More about Windmill Applications ...

Shielding and Grounding  
Protecting signal lines against electromagnetic interference is important if you want accurate, reliable, repeatable data. Although this may be a universally accepted statement, many overlook some of the sources of electromagnetic interference.
»More about Shielding and Grounding ...

Using Thermocouples - Part 2  
This time, in Part 2, we will look at some modern thermocouple specs. For example, you will see how linearity is effected by TC metallurgy, how mathematical models are used to plot response characteristics, how cold-junction-compensation is applied, and why linearization performed in the signal conditioner can be the best solution!
»More about Using Thermocouples - Part 2 ...

Thermocouples Part 1  
In this Part 1 application note "Introduction to Thermocouples", we explore the history of the thermocouple from its origins in the 1820s right up to its modern usage today!
»More about Thermocouples Part 1 ...

Hysteresis Specifications  
Hysteresis specifications are often combined with other phenomena such as repeatability, reproducibility, linearity, and dead band as part of the overall product specifications. However, some elements in a data acquisition system, sensors as an example, may have a denominate individual hysteresis behavior that should be considered in determining a total system error budget.
»More about Hysteresis Specifications ...

Strain Gage SCM's  
If temperature, pressure and flow are the most measured analog phenomena then pressure measurement in all its various forms – stress, strain, load, weight, torque, force, tension, etc – is perhaps the most difficult to master … our new application note, AN118, will use the bridge circuit to measure strain gages.
»More about Strain Gage SCM's ...

A Question from Dataforth’s President  
What’s next? As you use Dataforth’s products, and we manufacture hundreds of analog signal conditioners as well as data acquisition system solutions, I need to hear what you want next!
»More about A Question from Dataforth’s President ...

Unbalanced Voltages Increase Cost  
The electric 3-phase induction motor is the work horse of industry and represents a significant portion of industry’s electrical utility cost … An often overlooked phenomenon is that unbalanced three phase voltages are responsible for adding significant additional operational motor costs.
»More about Unbalanced Voltages Increase Cost ...

Dataforth Test Reports  
Fortunately, there are no mysteries or unexplained phenomena about Dataforth Signal Conditioning Module (SCM) products. Their published specifications and proven quality are facts of reality, which you can rely upon with certainty. To help to prove the point, you receive a test report with each Dataforth SCM.
»More about Dataforth Test Reports ...

Normal Mode Rejection, NMR  
The operational amplifier (OP Amp) with differential inputs is an essential component in industrial signal conditioning modules, SCMs ... Perhaps one of the most important design benefits of operational amplifiers is their ability to process differential inputs.
»More about Normal Mode Rejection, NMR ...

Bridge Circuit Measurements  
What are the differences among full bridge, half-bridge, quarter bridge circuits and voltage or current excitation of these Wheatstone bridge circuits? There's enough difference to present you with a six (6) page detailed application note!
»More about Bridge Circuit Measurements ...

Signal-to-Noise Ratio, SNR  
The ratio of an information signal to the noise associated with observing this signal is a figure of merit that describes the quality of a communication system. Consider for example the Voyager 2 Space Craft ...
»More about Signal-to-Noise Ratio, SNR ...

Accuracy versus Resolution  
Many times distinguishing between accuracy and resolution is misinterpreted in determining system needs. Some examples and illustrations are presented in this Application Note.
»More about Accuracy versus Resolution ...

Filtering - Phase Angles & Time Delays  
This newsletter, with the link to App Note AN113 can be considered as Part 2 to App Note AN112 "Filtering in Signal Conditioning Modules". This one provides design considerations relative to phase angles and time delays.
»More about Filtering - Phase Angles & Time Delays ...

Uncertainty Principle  
Heisenberg’s "uncertainty principle" ... (does not apply) ... in Dataforth’s products, which have specifications that can be precisely measured and directly observed in use.
»More about Uncertainty Principle ...

Galvanic Isolation  
Using batteries is one technique for developing circuits that are isolated. Designing "Galvanic Isolation" into your products is just as effective. Dataforth's signal conditioners are designed with full 3-way isolation - the signal path, the field circuit power supply and the system circuit power supply are each isolated!
»More about Galvanic Isolation ...

Signal conditioners - Buy vs Build  
Sure I'm going to be somewhat biased! We design and manufacture signal conditioners so my arguments are going to be in favor of buying the devices and not building them! Okay! But the reasons to buy them are very good ...
»More about Signal conditioners - Buy vs Build ...

Why Isolate?  
Many of us believe that if we don't have ground loops we don't need to isolate analog I/O signals. Our "Why Isolate" Application Note (AN116) exposes five very real, and very different reasons to isolate every one of your analog signals! ...
»More about Why Isolate? ...

Sampling Law  
Analog data is stored by modern acquisition systems in digital form. Therefore, analog information must first be transformed to its digital equivalent using an analog-to-digital converter (ADC). In this type of system, the sample rate MUST exceed the highest frequency contained in the “detectable” input signal ...
»More about Sampling Law ...

Resistor Thermal Noise  
Noise in measurement and control systems is generally considered to be EMI, electromagnetic interference. Unwanted voltages and currents induced by external magnetic fields, electric fields, ground currents, etc fall into the category of "noise" and often cause serious errors in low level instrumentation. ...
»More about Resistor Thermal Noise ...

Filtering in Signal Conditioning Modules  
Electrically and magnetically induced noise voltages or currents are inevitable. Field sensors with output voltages in the millivolt range are certainly degraded by induced noise levels on the order of volts. Consequently, signal conditioning modules must provide filtering to eliminate induced noise components ...
»More about Filtering in Signal Conditioning Modules ...

Filtering Noise  
Signal conditioning modules, SCMs, used for measuring process control variables such as temperature, pressure, strain, position, speed, level, etc. are always subject to externally induced noise signals. Noise sources in the form of electro-magnetically induced voltages (or currents) in industrial measurement and control systems are inevitable ...
»More about Filtering Noise ...

Power Supply Sensitivity  
System engineers use signal conditioning module (SCM) transfer functions as ratios of module outputs to sensor inputs in terms of units applicable to their particular system applications. ... System error budgets should always be initially analyzed to ensure that the combined impact of changes in environmental conditions ... are within acceptable system error limits.
»More about Power Supply Sensitivity ...

Measured vs Combinational Error  
Astute system engineers must determine an acceptable error budget associated with their system design and purchase system components with appropriate accuracy specifications. The accuracy specification attributed to an electronic component is the indicator of how much error can be expected in a particular component ...
»More about Measured vs Combinational Error ...

Signal Conditioning Article  
This month's Control Engineering (Jan'04) contains a good article on "Signal Conditioning - Why and How". It explores a few often overlooked reasons to use signal conditioning modules (SCM's).
»More about Signal Conditioning Article ...

Sampling Rates and THE LAW  
Nyquist criterion demands that we sample at GREATER THAN twice the highest frequency applied to our analog-to-digital converter (A/D). This is required to avoid aliasing errors from the A/D. Following this LAW will provide enough meaningful information from our A/D to determine the frequency content in the measured signal.
»More about Sampling Rates and THE LAW ...

System Throughput  
"Hello, that looks like an interesting data acquisition system! How fast is it and how much does it cost?" Apparently, simple questions that unfortunately, require complex answers! Yes, there are no simple answers to how fast and how much!
»More about System Throughput ...

Surge Withstand Capability  
Electrical surges due to lightening storms, brownouts, power interruptions, etc often cause catastrophic failures in electronic equipment. These surges can occur between any two wires; supply lines and earth ground, supply lines and common return (the white wire) and between individual supply lines.
»More about Surge Withstand Capability ...

Reproducibility - Repeatability  
Equally important to the dollar budget is the error budget, which is often overlooked or determined de facto by cost constraints. For optimum system performance, each individual system element needs an acceptable error allocation. In determining system error budgets, "repeatability" is often confused with "reproducibility".
»More about Reproducibility - Repeatability ...

Linearity and Conformity  
Data acquisition and process control systems function more efficiently and are easier to install if their field inputs are supplied by sensor signal conditioning modules which have linear transfer functions.
»More about Linearity and Conformity ...

Using Ethernet for Data Acquisition  
Networking engineers continue to have questions regarding the efficacy of Ethernet and where it comes down regarding determinism. Is it or isn't it deterministic?
»More about Using Ethernet for Data Acquisition ...

3-Phase AC Calculations Revisited  
This 3-phase application note is a continuation of Dataforth's Application Note AN109 which contains Single-Phase system definitions and basic rules for calculations. Both Single and Three-Phase documents include interactive Excel spreadsheets.
»More about 3-Phase AC Calculations Revisited ...

Single Phase Revisited  
All things change, nothing last forever; so they say. Electronic equipment changes in behavior are due to a variety of factors. For example, moisture, temperature, and age are just a few such factors...
»More about Single Phase Revisited ...

Industrial Data Acquisition  
So what does industrial data acquisition really mean? Sure, you want the device to be rugged, able to handle hostile temperatures and electrical environments. Of course, the device must be very reliable! ...
»More about Industrial Data Acquisition ...

Failure Rates  
How long can one expect an electronic unit to survive? The answer to that question is based on a statistical parameter called "failure rate". If one knows the failure rate of a device, then how long before the unit fails can be statistically predicted...
»More about Failure Rates ...

Drift Specs  
All things change, nothing last forever; so they say. Electronic equipment changes in behavior are due to a variety of factors. For example, moisture, temperature, and age are just a few such factors...
»More about Drift Specs ...

Input Resistance  
All instrumentation modules, which actively gather data, must extract energy from sensors in order to measure information. This "energy extraction" will, of course, create serious errors if allowed to be excessive. We see the significance of this error reflected as "input" specifications of signal conditioning modules.
»More about Input Resistance ...

When Good Grounds Go Bad  
Our article covers the common topologies used in industry to connect single-phase and three-phase systems. We describe and show how voltage distribution panels 'distribute' working voltages as well as neutral and ground wire connections.
»More about When Good Grounds Go Bad ...

Programmable Signal Conditioning  
Dataforth designs and builds "Instrument Class" fixed function conditioners that provide 0.03% accuracy. We also make programmable signal conditioners that provide a typical 0.1% accuracy from any voltage, current, thermocouple, or RTD input type and input range.
»More about Programmable Signal Conditioning ...

Signal Conditioning Tutorial  
Dataforth's twenty-six page signal conditioning tutorial has been a popular handout! So, we've turned it into an Adobe pdf file that you can now download and print or reference at your convenience....
»More about Signal Conditioning Tutorial ...

Buy versus Build  
Parts, and now days "inexpensive parts" are but a small part of an analog design. So, we've put together Dataforth's "Top Ten Reasons" you want to Buy (and NOT Build) your signal conditioners ...
»More about Buy versus Build ...

Common Mode Voltage  
Dataforth's isolated signal conditioners are designed with a patented isolation barrier that results in a common mode gain specification that is INDEPENDENT of the module's differential gain! ...
»More about Common Mode Voltage ...

Signal Conditioner Life  
In order to understand MTBF (Mean Time Between Failures) it is best to start with something else -- something for which it is easier to develop an intuitive feel. ...
»More about Signal Conditioner Life ...

Transient Protection  
Industrial equipment located in the "field" is exposed to electrical noise, power surges, and transient events such as static discharge or even, near by lightning strikes. An Instrument ClassTM Signal Conditioner from Dataforth provides ...
»More about Transient Protection ...

Analog-to-Serial  
Introducing the new SCM9B-D100 Series of isolated and software configurable single-channel data acquisition modules.
»More about Analog-to-Serial ...

Why True RMS?  
Application Note, AN101, is a six (6) page, in depth, presentation of why RMS (the Root-Mean-Square) approach is used to accurately determine effective values of voltage or current in AC signals.
»More about Why True RMS? ...

System Accessories  
We recommend a keep-it-simple approach when building a new test and measurement or data acquisition system. Approach your requirements from the sensor side and then move on up to the computer or controller end.
»More about System Accessories ...

New Application Note, AN104  
Last Newsletter we reviewed a Dataforth 2-Wire transmitter product ... This time we offer an excellent Application Note all about 2-Wire, 4-20mA, applications!
»More about New Application Note, AN104 ...

Measuring True RMS  
Just like using a hand-held multimeter to read AC voltages and currents, you can install a DIN package "Instrument Class(tm)" module in your control system to measure and present that same RMS data...
»More about Measuring True RMS ...

Test Reports  
Are you sure that your signal conditioners are performing properly? You need to be sure because ...
»More about Test Reports ...

Loop Isolators  
We've had lots and lots of application questions since Dataforth introduced its new family of loop isolators last year! ...
»More about Loop Isolators ...

Serial Data  
From all the articles on "fieldbuses", that is - Profibus, DeviceNet, CAN, ModBus, and others, one would think that these busses dominate. NOT TRUE! Good old RS-232 and RS-485 are still used in over 75% of process control networks...
»More about Serial Data ...

It's about isolation & protection...  
Here's a good analog I/O refresher -- our new seven page white paper tells you everything you need to know about solving problems of ...
»More about It's about isolation & protection... ...

Quick Reference  
... for RS-232C, RS-422, RS-423, RS-485 ...
»More about Quick Reference ...