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Interface Instrumentation Definitions

The new Interface Instrumentation Selection Guide is a great way to get started in choosing the right instrumentation for your next project or lab. To serve as additional resources, here are key instrumentation definitions that can also help you make the best decision regarding the type and model of instrumentation that will work best with your sensor.

Instrumentation Selection Guide Definitions

Excitation
A Wheatstone bridge-based sensor, such as a load cell, requires excitation voltage to operate. The excitation voltage is typically 10V; however, many instruments supply lower voltage, an 2.5V, 5V, and others. Since these sensors are ratiometric, Interface instrumentation devices are designed to pair with these types of sensor products.

Signals
The output signal from a load cell is expressed in terms of mV output per V of excitation, at capacity. For example, a 100 lb capacity load cell rated for 2 mV/V output will have 20mV output at 100 lb, when excited with 10V. Because the output signal is directly affected by input voltage, it’s important to maintain a stable excitation voltage, which our instrumentation does.

Signal Conditioners
A signal condition provides stable excitation voltage to the sensor and amplifies the low-level sensor signal to a high-level output such as +/-5V, +/-10V, 0-20mA, 4-20mA, 0-5V, or 0-10V.
Many of our products include filtering, which can help reduce noise in the output signal.

Data Acquisition Systems
A complete data acquisition system consists of DAQ hardware, sensors and actuators, signal conditioning hardware, and a computer running DAQ software. Interface provides DAQ instrumentation that are ideal for completing a sensor-based system. Many data acquisition systems require high-level inputs such as +/-10V and don’t work very well with low level mV signals. Interface instrumentation solutions do work well with DAQ systems. The DAQ doesn’t necessarily supply a stable excitation voltage like the Interface sensors do.

Interface Modules
An interface module converts the low-level mV/V sensor signal to a digital format that can be transmitted to a computer, (PC or laptop). Popular interface modules provide USB, wireless USB, or Bluetooth data transmission. Software is normally provided and allows data display, logging and graphing. The interface modules are commonly used when data needs to be logged to computer and you are not using an existing data acquisition system. The interface module advantages over standard data acquisition is ease of use and they are normally plug-n-play. Considerations when selecting this type of instrumentation include bit resolution, number of channels, sample rate, software features and type of output.

Indicators
Interface indicators provide stable excitation voltage and converts the sensor signal to a digital display. Commonly available features include analog or digital output, selectable digital filtering, peak and valley monitoring and set point outputs. Things to consider when selecting an indicator are internal sample rate and update rate of analog output.

Wireless Telemetry System (WTS)
Wireless is very popular today. Interface’s Wireless Telemetry System is easy-to-use providing wireless data communication between a load sensor and a receiving indicator. The WTS is capable of receiving multiple inputs and is fully compatible will all Interface force sensors. The WTS comes calibrated, tested and ready-to-run. The charge lasts up to three months using AA batteries.  You can see the complete WTS and Bluetooth Telemetry System comparison here.

When selecting the type of instrumentation you need to pair with your measurement device, some additional things to consider are power supply requirements, amount of filtering, fixed or adjustable filtering, input range, scalability and zero adjustment range. Our instrumentation can accommodate these requirements. To get started on picking the instrumentation solution that fits your requirements, go to the Interface Instrumentation Selection Guide.

We’ve provided a quick visual reference of Interface’s instrumentation types and correlating models.

All Interface Instrumentation product details are listed by product model name. You can find product specifications, as well supporting datasheet for each product by going here.

 

Additional Resources

Instrumentation Analog Versus Digital Outputs

Introducing New Interface Instrumentation Selection Guide

Advancements in Instrumentation Webinar Recap

Recap of Inventive Multi-Axis and Instrumentation Webinar

Recap of Instructional on Instrumentation Webinar

Digital Instrumentation Brochure

Instrumentation Brochure

 

Instrumentation Analog Versus Digital Outputs

Interface sells a wide variety of instruments designed to help take data measured on a load cell or torque transducer and convert it into a readable form. Within this expanding family of instrumentation offered by Interface, there are two types of output methods available: analog or digital.

By far, analog output for test and measurement instrumentation has been the most popular. Analog output is measurement represented in a continuous stream. Technologies have advanced a growing demand for more advanced data capture. Digital instrumentation uses digits as the output, providing greater measurement accuracy and digital resolution.

Understanding which output is best for your project is important in getting the right communication capabilities to use with the designated sensor components. It’s an important consideration whether you are designing a new testing system or working with an existing program and looking to add new instrumentation.  You can gain further insights by watching our Instructional on Instrumentation webinar here.

Here is a brief explanation on the difference between analog and digital instrumentation, along with advantages of each.

Benefits of Digital

Digital outputs are becoming more and more popular for several reasons. The first is that they often incur lower installation costs than their analog counterpart. Digital also works across existing networks. For instance, if you have ethernet IP you can interface directly into it as opposed to running analog signals.

Digital outputs are also far more scalable than analog because a lot of the time you can replace sensors without causing a disruption. Multiple sensors can also be daisy chained into a single cable run, meaning the user can piggyback into an existing network rather than running cables back to a controller. This is one reasons the installation cost is often lower.

There are also built-in error detections with digital outputs to detect things like open legs and bridges. And if you’re digitizing at the sensor, the system is less susceptible to noise because digital signals are natural noise immune.

Benefits of Analog

With all the benefits of digital, why would someone still choose the older output method of analog? Analog signals are still faster than digital and are much easier to work with. Additionally, analog systems take up far less bandwidth than digital. Therefore, if you’re in an area with low-bandwidth, digital output solutions may slow the network down, while analog will not.

It is important to note that many DAQs and PLCs accept analog signals, so if the user wants to stay with what they already have in house, analog may be the better option.

Choosing Analog or Digital

When deciding between analog and digital instrumentation output capabilities, it’s important to consider the following questions as well:

  • Are you connecting to an existing network? For instance, if its CAN bus, you may want to use CAN bus sensors. But, if it’s pure analog, you’re not going to want to convert everything over to digital unless there are other factors driving this move?
  • Are you connecting to an existing DAQ device? If your system has available analog input channels, you may be fine with analog output. If it doesn’t, you may have to add extra channels. Or say the system has an EtherCAT connection, you can use the same DAQ without adding channels by interfacing with it digitally.
  • What is your budget? If your network already has a lot of analog systems, the cost of staying with analog may be worth it. If you must add channels to your DAQ, but you have digital interfaces available, that may allow for cost savings based on how many channels and sensors you need.
  • How many sensors are you connecting? If you have a lot of sensors, the obvious answer is digital because of the flexibility it provides, and the limited cable runs needed. But if you don’t need many sensors, analog could make more sense.

There are several considerations to make when choosing digital versus analog.  You can learn more about which options suit your project requirements by reviewing the online specs of our range of instrumentation solutions.

There is also considerable detail in the many options available in our Instrumentation Overview here.

Additional Instrumentation InterfaceIQ Posts

Instrumentation Options in Test and Measurement

Instrumentation Application Notes

Force Measurement Instrumentation 101

Digital Instrumentation for Force Measurement

Recap of Instructional on Instrumentation Webinar

Interface recently hosted a new ForceLeaders event on the topic of instrumentation.

The webinar experts, Keith Skidmore and Ken Bishop, shared insights and experience in different types of instrumentation. Along with detailing various features, they provided valuable tips for testing engineers, metrologists, and sensor users on how to choose the right instrumentation for your upcoming projects or new systems.

The discussion featured a series of instrumentation types, benefits and uses cases, which you can now watch online by visiting our training and events page here.

The types of instrumentation detailed during the webinar showcases the range of products we offer and that are available to complete any testing solution.  These products range from simple boxes to complete telemetry systems used for field and wireless communication requirements. The webinar highlighted the following range of instrumentation options:

  • Signal Conditioners
  • Indicators
  • Data Acquisition
  • Portable Load Cell Indicators
  • Weight Indicators
  • Junction Boxes
  • USB Interfaces
  • TEDS Ready
  • Wireless and Bluetooth Telemetry Systems

The experts offered guidance on the topic of analog versus digital and wireless versus Bluetooth. They also provided some simple criteria to review when deciding what type of instrumentation fits your exact requirements.

Basic Criteria for Selecting Digital or Analog

  • Is there an existing network you need to connect to?
  • Are you connecting to an existing DAQ device?
  • What is your budget?
  • How many sensors are you connecting?
  • Do you need to communicate through a bus?

For more insights into application use cases, frequently asked questions and top 10 tips, be sure to watch the event.  Here are just a few of the tips shared during the Instructional on Instrumentation presentation:

Tip #1 – Know your power supply requirements, amount of filtering that is fixed or adjustable, input range, scalability and zero adjustment range.

Tip #2 – The output signal from a load cell is expressed in terms of millivolt output per Volt of excitation, at capacity. 

Tip #3 – The output signal is directly affected by input voltage. It’s important to maintain a stable excitation voltage.

WATCH THE RECORDED LIVE EVENT: INSTRUCTIONAL ON INSTRUMENTION

If you have missed any of our ForceLeaders webinars, be sure to visit our YouTube Channel.  We have recorded all the events for your convenience.  Our experts are also here to help you get the exact instrumentation based on your unique requirements. Contact us here for questions or technical assistance.

Additional Resources:

Instrumentation Options in Test and Measurement

Digital Instrumentation for Force Measurement

Force Measurement Instrumentation 101

Interface Load Cell Indicators

At Interface, our claim to fame is that we offer the most accurate and reliable force measurement devices on the market, from load cells to torque transducers and everything in-between. However, no test is complete without the system used to gather the data to evaluate performance results. That’s why we provide a wide variety of instrumentation solutions that include signal conditionersoutput moduleshigh speed data loggersportable load cell indicators, and weight indicators to complete any testing system.

Among the Interface instrumentation products, the most frequently purchased with a force measurement devices are our load cell indicators in various models including handheld, digital, wireless, multichannel, programmable, output modules, analog and bidirectional.

What is a load cell Indicator?

A load cell indicator is a high-accuracy device connected to the output of a load cell to amplify and display the value of the measured load force and weight. Load cell indicators are often needed where the force, load, or weight measurement needs to be visually displayed for the user and displaying the results on a PC is not feasible or desired in the testing environment. For example, testing in the field or confined spaces can make it impossible to connect directly to a PC. In these situations, indicators are used to quickly review and capture force data in real-time.

A few key benefits of load cell indicators include that they provide stable excitation voltage and converts force measurement sensor signals to a digital display. Commonly available features include analog or digital output, selectable digital filtering, peak and valley monitoring and set-point outputs. Additionally, each load cell indicator can be used to connect to four (or more) digital load cells and can display individual readings or the sum of all connected load cells.

Need a load cell indicator?

Interface offers a wide variety of load cell indicators in multiple configurations. Interface indicators come in single to multi-channel weight transmitters and can be found in handheld and portable designs. Things to consider when selecting an indicator are internal sample rate and update rate of the output. A few of our most popular indicators include:

9890 Strain Gage, Load Cell, & mV/V Indicator

Model 9890 is a powerful multipurpose digital load cell meter ideal for weight and force measurement applications. With a max current of 350 mA at 10 V, it can support up to 12 load cells making it perfect for multipoint weight measurement purposes. The dual-scale capability allows for displays in two different units of measure. See a demonstration video here.

9320 Battery Powered Portable Load Cell Indicator

Model 9320 is a bipolar 7-digit handheld meter featuring two independently scalable ranges, peak and valley monitoring, display hold, mV/V calibration, and a power save feature. Typical battery life exceeds 45 hours of continuous use and 450 in low power mode. IEEE1451.4 TEDS Plug and Play compliant.

482 Battery Powered Bidirectional Weight Indicator

Model 482 is battery powered, bidirectional, and comes in a NEMA 4X stainless enclosure. Standard options include 523,000 internal counts, 0.8-inch LCD 6-digit display and a measurement rate that goes up to 40 Hz. Available options include analog and relay outputs.

1280 Programmable Weight Indicator and Controller

The Interface 1280 Series programmable digital weight indicator with color touchscreen, web server view and multiple protocol types delivers uncompromising speed for today’s operations and expansive options for tomorrow’s requirements.

INF4-Ethernet IP Weight Transmitter and Indicator

The Interface INF4-Ethernet IP weight transmitter and indicator has a six-digit red LED display (8 mm height), space-saving compact design, four buttons for the system calibration, and a six-indicator LED.

See all the indicator options here.

Load Cell Indicator Application Note

The application note below provides an example of the benefit of a load cell indicator in real-world use within the medical industry.

A pharmaceutical tablet producer wanted to monitor the forces applied by the tablet forming machine to understand the relationship between raw material, die set, forming force, and motor-cycle speed. The goal was to improve productivity and efficiency of the tablet forming process while reducing losses, such as cracked tablets or voids, by adding a dimension of feedback that could be used to assign specific press adjustment criteria for given inputs.

An Interface Model WMC Sealed Stainless Steel Mini Load Cell (10K lbf Capacity) was mounted in the section of the downward press bar. The machine was modified to accomplish this. The load cell was then connected to a Model 9320 Portable Load Cell Indicator to collect the needed data.

The indicator was selected as the data collection device because a laptop could have interfered with the test cycle due to space restrictions. The output of the load cell was connected to the 9320 Portable Load Cell Indicator and set aside so that the cable did not interfere with the cycle and no snagging would occur. A cable tie was used to stow aside the cable and to ensure there was enough clearance for the entire cycle.

After analyzing the data, the tablet producer was able to quantify adjustment levels by monitoring which forces produced the most optimal results for a given cycle speed, die set, and raw material. Productivity and efficiency were greatly improved by the enhancement of the data feedback.

To learn more about Interface load cell indicators and for a complete list of products, you can download our instrumentation brochure here. You can also read more about instrumentation options in test and measurement in this post.