DAQ Dictionary: P-Q

The new part of DAQ dictionary you’ve been waiting for so long is finally out. This time we bring your P and a little bit of Q. Actually, we’ve only got one word with Q, you’ll see.

PAL

Phase Alternation Line
The color television coding system generally used for European broadcasting.

PC

Personal computer. Generally applied to computers conforming to the IBM designed architecture.

PCI

Peripheral Component Interconnect. A local bus standard developed by in 1992. PCI cards plug into your computer and are configured through software. They do not have jumpers or switches.

PCMCIA

Personal Computer Memory Card International Association. The industry group that developed the specification for credit card-sized plug-in cards for laptop computers.

Peer-to-Peer Communication

A communication between networked devices in which any device can initiate data transfer.

PID

Proportional gain, integral action time and derivative action time. PID software, for example, compares an analog input value with a setpoint and if there's a discrepancy outputs an appropriate analog or digital control value, according to the PID calculations.

PI&D

Piping and instrumentation diagram.

Ping Utility

This is a test utility which sends a message to a defined port within your instrument. The instrument replies with a short data message. Virtually every unit on TCP/IP will support this action. If you cannot Ping your instrument, and it is on a TCP/IP network, you will not be able to talk to it.

PLC

Programmable Logic Controller.

Pole

A relay contact.

Port

The external connector on a device.

Positive Edge Trigger

Data acquisition starts when an input signal changes from a low to a high state.

Positive Temperature Coefficient

An increase in resistance due to an increase in temperature.

Precision

The repeatability of a measurement. The ability of an instrument to give the same reading under repeated identical conditions.

Protocol

A set of rules used in data communications.

Pulse

A temporary change in voltage of any length.

QA

Quality assurance.

C# Class Libraries in LabVIEW Applications

Knowing how to incorporate C# libraries into a LabVIEW based project can be an extremely helpful apparatus. There are many reasons why you would need to incorporate C# dll's into a LabVIEW extend however the two that surface frequently for me is reusing legacy code that was at first written in C# and composing a C# wrapper when needing to utilize an outsider driver or library.
Some of the time it's less demanding to compose the wrapper in C# and afterward actualize the library specifically in LabVIEW. While interfacing specifically to an outsider driver/library, the LabVIEW code to finish a moderately straightforward assignment can be extremely chaotic and bulky to peruse; subsequently the C# wrapper with basic usage in LabVIEW is my favored technique.
Adding a frame application to your answer permits you to test the library in the environment that it was composed. By testing the dll in C#, you can get prompt input to your dll improvement. On the off chance that there are issues with the dll when you move to LabVIEW, you realize that the usefulness is working so the issue is more than likely in the LabVIEW execution.
A typical bug in LabVIEW is that the callback vi stays held for execution even once the references are shut, the occasion has been unregistered and the application has been halted.
An approach to get around this is to incorporate a summon hub once every one of the references have been shut. Right tap on the conjure hub and select the accompanying: Select Class >> .NET >> Browse >> mscorlib (4.0.0.0) >> System >> GC >>
When this technique is put on the square chart, the callback occasion vi will never again be saved for execution.
In synopsis, this is an extremely straightforward usage of making a C# Class Library, testing it utilizing a C# Form Application and afterward utilizing the Class Library as a part of a LabVIEW extend.

Questions to Ask Before Buying A Data Acquisition System

So you need a DAQ system. Congratulations on your decision, but, don’t rush and buy the first one you see on the market. Research. Ask questions. Here’s a list of the most important questions to ask when buying data acquisition system.

What do you need it for?

Classic data logging and Data Acquisition (DAQ) solutions focus on gathering data to determine the effectiveness or upkeep timing. Try to look for a system that will fit your specific needs, maybe even go for a custom built device as well as data acquisition software.

How fast is it?

Data loggers are usually able to acquire data at speeds of up to 1Hz (once a second). More often than not, this will affect the price of a device. If you need top speed device go ahead and get one, but if your project does not require high-speed data logger don’t waste money on that factor, invest it where you’ll need an improvement.

Alarm?

Would you like to be notified instantly in case the readings are higher or lower than expected? Many devices offer the option to push notifications via SMS, email, sound an alarm or even a phone call.

What kind of sensors do you need?

This is essential and is connected with the question number one. Don’t miss an important sensor or get those you don’t need. If you’re looking for a temperature data logger, get one with only those sensors.

Memory?

How often will you download data from the data logger and how much information will you need will give you the answer to this question. You may need only a couple of minutes a day recorded or you may want the device to save readings 24/7.

Location?

A device can be fixed to a location or a portable one you’ll carry with you. In case the device is constantly fixed at a certain location, you’ll need to make sure it is durable for the conditions in there. If it measures water, it has to be waterproof. It may sound obvious, but many people overlook these factors and regret it later.
These are only the essentials. There are more factors and specifications you’ll need to look into and we’ll talk about that in some of our future articles.

DAQ Dictionary: O-P

This edition of DAQ dictionary brings us closer to O and P. Data acquisition is a vast field, but every step gets us closer to completely mastering it.

OEM

Original Equipment Manufacturer. A company which makes basic computer hardware for other manufacturers to build into their products.

Offset Error

If you get a reading other than zero for a zero condition then you have an offset error: every reading will be inaccurate by this amount.

Ohm

SI unit of resistance, such that one ampere through it produces a potential difference of one voltage.

On-Off Control

A simple control system which is either on or off.

Output

Information leaving a device.

PAL

Phase Alternation Line.

PC

Personal computer. Generally applied to computers conforming to the IBM designed architecture.

PCI

Peripheral Component Interconnect. A local bus standard developed by in 1992. PCI cards plug into your computer and are configured through software. They do not have jumpers or switches.

PCMCIA

Personal Computer Memory Card International Association. The industry group that developed the specification for credit card-sized plug-in cards for laptop computers.

Peer-to-Peer Communication

A communication between networked devices in which any device can initiate data transfer.

PID

Proportional gain, integral action time and derivative action time. PID software, for example, compares an analog input value with a setpoint and if there's a discrepancy outputs an appropriate analog or digital control value, according to the PID calculations.

PI&D

Piping and instrumentation diagram.

Ping Utility

This is a test utility which sends a message to a defined port within your instrument. The instrument replies with a short data message. Virtually every unit on TCP/IP will support this action. If you cannot Ping your instrument, and it is on a TCP/IP network, you will not be able to talk to it.

PLC

Programmable Logic Controller.

Pole

A relay contact.

Port

The external connector on a device.

Positive Edge Trigger

Data acquisition starts when an input signal changes from a low to a high state.

Positive Temperature Coefficient

An increase in resistance due to an increase in temperature.

Precision

The repeatability of a measurement. The ability of an instrument to give the same reading under repeated identical conditions.

Protocol

A set of rules used in data communications.

Pulse

A temporary change in voltage of any length.

3 Reasons to Automate Software Testing

You’re not a true developer if you don’t firmly believe that software is capable of anything. If you do believe this, then, why can’t software test a software? Got the point? Congrats, you’ve successfully completed the first step towards automation testing.
Now you’re probably wondering if that the right thing to do. Let’s see the top three reasons why you should start with the automated testing  today.

#1 Regression

We’re humans. Testing requires repeating the same tasks, over and over again with the same speed, energy, attention, and accuracy. I repeat, the same tasks, over and over again. Let that sink in. How long do you think someone will be able to last like this? A week? A month? A year? It’s obvious that this is the job for machines, for a software that is programmed to function like this.

#2 Some tasks cannot be done manually

Depending on the field you’re working in, there are some tasks that simply have to be automated. For example, comparing two images pixel by pixel. You don’t need to be a doctor to know that a human eye is not capable of detecting such differences. Testing automation is the ally you need in this scenario. Some other examples include comparing two spreadsheets with thousands of rows and columns, testing the app under the weight of 100k users or performance benchmarks.

#3 Parallel testing

Although it is theoretically possible, testing an app on different browsers and multiple operating systems at the same time is virtually impossible. Not only the tester would need several computers, they’d also need a couple of extra pairs of hands and eyes. How many SQA’s did you meet that match the criteria?
Automation is your friend and ally. There’s no need to be afraid of it, there is still going to be someone watching over it, it just takes out the frustration out of the equation. What are you waiting for?

DAQ Dictionary: M-N

In the newest edition of DAQ dictionary, we explain terms starting with M and N. We're at the half of the alphabet already and I bet data acquisition seems closer now.

m

The symbol for meter also used to indicate a thousandth part of something (milli)

M

The symbol for mega (million).

Mains

The source of electrical power, normally the electricity supply system.

Mains Frequency

Electricity AC supply frequency; 50 Hz in the UK, 60 Hz in the US.

MES

Manufacturing Execution System.

Metre

The SI fundamental unit of length, equal to 1.093 yards. (Meter in US.)

MIS

Manufacturing Information System.

MMI

Man Machine Interface. Also known as the human-machine interface. The communication between the computer system and the people who use it.

Modular

A form of construction in which hardware or software units, often with differing functions, are quickly interchangeable.

Multiplexing

Where each signal is switched in turn to a single analogue-to-digital converter. As opposed to where one A-D converter is used for each signal in simultaneous sampling.

Modbus

An industrial networking system that uses peer-to-peer communications. More details on Modbus are in Issue 32 of Monitor.

Most Significant Bit, MSB

In a binary number, the 1 or 0 furthest to the left.

N-Type Thermocouple

Nicrosil-Nisil thermocouple with a temperature range of -200 to 1200 oC.

Name Server

When communicating with instruments over a TCP-IP network, and your computer wishes to send a message to a named destination, it asks a Name Server to resolve the name to an IP Address. Your computer needs to know the IP Address of the Name Server. You can view this in the TCP/IP properties of the computer.

Negative Edge Trigger

Data acquisition starts when an input signal changes from a high to a low state.

Network

The physical interconnection of devices sharing a communications protocol.

Node

A device with a direct point of access to a network.

Noise

Any unwanted electrical signals contaminating the signal to be measured. This noise may be electronic noise which is an artifact of semiconductor construction techniques and is not reducible.Alternatively, the noise may be caused by environmental factors. This type of noise can be the result of poor positioning or screening of signal wiring. This may result in mains frequency or RF pickup contaminating the required signal.

Non-Conforming

A product outside manufacturing limits but not necessarily defective.

Non-Destructive Testing

The method of inspecting materials and products without affecting their subsequent properties and performance. Abbreviation NDT.

How it Feels to Manually Test

You’re hired! Great! You’ve got the job as a software quality assurance, just what you’ve wanted, right? Let’s take a look at your time spent at work, starting from day 1.

Day 1

You’ve happily walked into your office and there’s already a task waiting for you. Some application needs to be tested, and there are hundreds of forms, each with at least fifty-or-so fields, and even larger number of reports. That’s fine, you’re educated for all of that,  and you know what needs to be done. After an hour or so, you encounter an error. Perfect! You feel like you’ve already started contributing, you keep up with your work and find few more bugs by the end of the day.

Day 2

Like yesterday, you feel energetic, confident and ready to hunt down some errors. The bugs from yesterday were fixed, now it’s time to find if there are any more left. You pay attention to every detail and encounter more errors today, you’re getting better.

Day 3

A newer version of the app is out with minor bug fixes. You need to go all over again to check the same forms if there are any new errors. You start to feel a little bit bored, I mean, it’s the same mindless thing all over again.

Day 30

Fast forward to the end of the first month at your new job. New versions of the app come out every now and then, and you have to go through the same forms and reports all over again, countless times. You no longer feel energized and confident, you’re tired. Here and there, you begin to skip some of the steps, some bugs slip through, and you (as well as your employer) begin to question your competence. Let me stop you right there. You are not alone. Just like most of the SQA’s, you get in the phase where our “human” kicks in. You are not able to perform 100% accurately every hour, every day.
This is why we promote automated software testing, and this is just one of the reasons. ReadyDAQ’s automation technology will your and you’re employee’s precious time, money and energy. Why not invest those into something else?

DAQ Dictionary: J-L

For the first the since we've started publishing DAQ dictionary, we have an article with 3 letters in it: J,K and L. Enjoy and get even more familiar with data acquisition!
J-Type Thermocouple
Iron-constantan thermocouple with a temperature range of 0 to 750 oC.
k
A symbol for a thousand, from a kilo.
K
A unit of stored data. 1K = 210 = 1024. Also, stands for a degree on the Kelvin temperature scale.
Kelvin
A temperature scale which is one of the seven base units in the International System of Units (SI). The symbol is K.
K-Type Thermocouple
Chromel-Alumel thermocouple with a temperature range of -200 to 1200 oC.
<LF>
A Line Feed. A "non-printing" character which often terminates a message from an instrument plugged into the computer's COM port.
LAN
Local area network. A data communication system connecting devices in the same vicinity. Data is transferred without the use of public communications. Examples of LANs are Ethernet, token ring and Modbus.
Least Significant Bit, LSB
In a binary number, the 1 or 0 furthest to the right.
LIFO
Last in first out. Describes a stack method of data storage.
LIMS
Laboratory information management system.
Linearity
Ideally, an A-D or D-A converter converts the input or output range into equal steps. In practice, the steps are not exactly equal. Linearity, or non-linearity, is a measure of how close the steps approach equality.
Load Cell
A transducer which converts a force into an electrical signal. It normally comprises four strain gauges in a Wheatstone bridge arrangement.
Loopback Test
A signal is sent out and returned as a way to determine whether the COM port is working correctly. It is used to troubleshoot serial communications.
Low Pass Filter
This lets through the lower frequencies and attenuates the higher frequencies. Choose the cut-off frequency to be compatible with the unwanted frequencies, the frequencies present in the signal you are measuring, and the sampling rate of the analogue-to-digital converter.
LVDT
Linear Variable Differential Transformer. Used in measuring devices that convert changes in physical position to an electrical output.