Responsible for channeling both power and communication between the load cells and the indicator, load cell cables are an integral part of building a custom scale. Though not just any cable will work. See, load cell cables are selected based on the distance between the two parts, as well as certain environmental conditions like temperature, contact with abrasive or flammable materials, or even rodents.
Before you can know the right type your custom scale project needs, it is best to have an understanding of the different types of load cell cables available.
4-Wire Load Cell Cable
Perhaps the most common cable, the 4-wire load cell cable is used primarily for short distances. As its name suggests, this type consists of four wires:
Power (excitation) +
Signal (output) +
Once connected, the cable should run from the scale to the indicator display. These wires are calibrated and designed to handle the surrounding temperatures. Many custom scale projects use the 4-wire load cell cable since it is more affordable and suitable for most scales. However, should you need additional length or if your scale is in an unpredictable environment, you may need to reconsider the type of load cell cable you are using.
6-Wire Load Cell Cable
Designed for longer distances and more difficult settings, the 6-wire load cell cable offers a lot more options. Again, as the name suggests, these load cell cables have six wires. They contain the four found above, as well as positive and negative sense wires. The long distances that 6-wire load cell cables cover can subject them to changes in resistance, temperature, and dips in voltage. The addition of these two sense wires helps to keep things flowing steadily.
Because they are not thermally compensated as the 4-wire load cell cables are, the 6-wires can be cut and used alongside other cables with no issue – making them perfect for larger commercial custom scale projects.
Types of Load Cell Cable Shielding
While 6-wire load cell cables offer a lot of benefits when designing a project, it is important to note the surrounding environment and opt for shielding that will protect the cable from any outside environmental factors. Below are the most common types of load cell cable shielding.
Hostile Environment Cable
Hostile environment cable is best used in environments that are, well, hostile. Depending on where the scale is being used, the cables may come in contact with harsh or abrasive substances, such as fuel, ether, or even salt. Over time, these substances can damage the cables.
Hostile environment cables are created with a polyurethane jacket that acts as a barrier against these damaging substances, keeping the cable safe and the scale running smoothly.
Rodent Protection Cable
Rodents and their incessant chewing may seriously interfere with a scale’s functionality. If in an environment where there are rats, mice, or other pests, the load cell cable may become enticing – leaving you with hefty costs to replace some or all of the cable.
Rodent protection cable is a type of cable that protects against this pesky situation. The outside layer of the cable is a braided shield making it difficult to chew. And, as an added defense, it is coated with a chemical that will discourage them from wanting to ever take a second bite.
Intrinsically Safe Cable
Flammable gases or liquids or generally hazardous materials can be damaging to load cell cables, requiring added security in the form of a jacket. For intrinsically safe cables, industry-standard blue double jackets are used to protect the cables from exposure to these dangerous materials.
In environments where the temperatures fluctuate or reach extreme highs, load cell cables need an outer covering that will protect the wires regardless of how hot it gets. A high-temperature cable is designed with a fluorinated ethylene propylene (FEP) jacket that insulates the wires and can withstand the heat without getting damaged.
Should I buy a truck scale with weigh bar sensors? The Avery Weigh-Tronix Weigh Bar® was designed to overcome the shortcomings of the traditional strain gauge load cell and to provide the end user with a rugged, highly reliable and linear load sensing device at reasonable cost.
More than twenty years of extensive use in industrial, farm and transportation applications has demonstrated that the Weigh Bar has met these requirements. The unique, robust design of the Weigh Bar is the primary reason for this success.
The Weigh Bar has proven itself over the past 20 years to be one of the world’s most robust weight transducers manufactured today with over 500,000 installations world-wide.
The IP67 Weigh Bar design provides inherent strength and overload protection, while also providing accuracy and high reliability. A significant contributor for this is the positioning of the gauges on the outside of the Weigh Bar. More robust than a shear beam load cell for a given output – a shear beam load cell will reach its peak fatigue point much sooner than a Weigh Bar.
The unique design of the Weigh Bar allows simple calculations to be made by the indicator, eliminating several types of errors:
• End Loading – When an end load is applied to the Weigh Bar, it is subjected to a uniform compressive strain throughout its length – all sensors detect the same strain. • Torsion Effects – When torque is applied to the Weigh Bar, a uniform torsional shear strain is developed through the length of the bar – both sensors detect the same strain. • Side Loading – When a side load is applied to the Weigh Bar, it acts as a beam, but at a 90-degree angle. When this occurs, the neutral axis of the beam (the point in the beam where neither tension or compression occur) falls directly under the center of the strain gauges. No apparent strain is seen by the gauges. • Vibration –The fine grain structure of aircraft quality steel is resistant to vibration fatigue and induced error. The strain gauges and adhesive used are also vibration and fatigue proven.
Load Cells – The Avery Weigh-Tronix Weigh Bar® Weight Sensor
The exclusive Avery Weigh-Tronix Weigh Bar® is an extremely rugged, highly reliable, load sensing device. Over several decades, the Weigh Bar® has built a reputation for precision, reliability and durability that no other load cell can match.
Weigh Bar – Reduced cost of ownership
Precision machined from aircraft quality, alloy steel, the Weigh Bar® offers excellent repeatability and long-term durability, reducing cost of ownership and need for load cell replacement.
Rugged Weight Sensors
With up to ten times more steel content than shear beams or compression cells, it absorbs impact to minimize peak forces and is virtually fatigue-proof. The Weigh Bar® is proven to resist electrical surges and is protected by a limited warranty that includes coverage against lightning damage.
Accurate Weigh Bar
The sensor’s design automatically cancels the effects of side loading, end loading and twisting, resulting in quick, accurate readings which are achieved regardless of temperature change, vibration, and shock loads on the scale.
Sealed “Load Cell”
The standard alloy steel Weigh Bar® is well protected against harsh environments by an exclusive 5-layer, sealing process. For the most challenging locations hermetically sealed stainless steel weigh bars are available.
A lot of customers are curious about this question… how long should a truck scale last? Or perhaps it’s phrased like this… how do I know when my truck scale needs to be replaced?
The vast majority of truck scales are located outside. This means the scales have the hot sun blazing down on them all summer (every year). Then, they have the piles of snow on them in the winter (every year). In between all the hot and cold extremes, they have all the rain that you typically see fairly often.
So, with all the weather conditions, that means a truck scale must be able to withstand all the environmental challenges while working reliably and accurately…. For years and years! And, be able to handle 80,000 lb vehicles everyday!
So, how long can I expect my truck scale to last?
That’s a really good question and it’s a question that has a variety of answers.
Depending on the environment and application, most truck scale owners can typically expect a truck scale to last anywhere from 15-30 years.
If your location consistently has over 250 trucks a day going over the scale (or you project it will eventually have that kind of truck traffic) then you will need to choose a truck scale built for that kind of traffic. Choosing an “economy” or standard duty truck scale in that situation may be cost effective now… but will most likely lead you to have a shorter truck scale life and force you into looking for scale replacements or weighbridge repairs sooner than you would prefer.
Sometimes spending an extra few thousand dollars up front will allow you to purchase a heavier duty “HD” scale that will last you significantly longer than the “SD” model. What’s an extra few thousand dollars when you average it out over twenty-five or thirty years of use? Especially if the extra cost helps you gain an extra five or ten years of scale use?
Can I Repair My Truck Scale Instead of Buying a New One?
This is a good question and a common question that a lot of people ask when they have an old truck scale. In most cases, the answer is yes. Depending on the age of the truck scale and severity of the issues, repairing a truck scale can certainly work and be a cost savings.
However, once a truck scale has been in service for over 20 years or so… repairs may not be the best choice. Often you will hear people refer to the scale repairs as “band-aids”. We understand what they’re referring to, but the truth is that truck scale repairs on a 20+ year old scale weighbridge are just that, repairs…
A “band-aid” is supposed to heal your wound and help you get back to 100%. A “band-aid” on a 30 year old truck scale is not going to “heal” the scale. It is simply designed to get a few more years out of the scale before the scale will need to be replaced.
Unfortunately, truck scales that have been repaired often don’t last as long as you would like. One of the reasons is simply the age of the steel and the components. Often the areas that were repaired may be ok after the repair, but then the other areas that were doing ok before the repair, are now starting to fail.
When you think of a truck scale overhaul, the Truck Scale components can usually be replaced… things like load cells, junction boxes, summing boards, etc…, but the core weighbridge construction and integrity are sometimes challenging to rebuild in a cost effective & timely manner…. especially in a scale that’s 25 or 30 years old… or older.
It’s also important to look at the actual repair costs. Sure it can be overwhelming when you see a $50,000 quote for a new truck scale. However, if you attempt to repair and put “band-aids” on a 25 year old truck scale, how much money is that going to cost? Between materials and labor, we’ve seen these repair costs rise above $3000. Plus there is down time where the scale can’t be used.
And even after the scale is repaired, there really is no guarantee or warranty that the scale is going to last X number of additional years. So, in this example, you could spend several thousand dollars on scale repairs that may get you a few more years of service…. or, that $3000 could be used to help pay for a new truck scale.
Planning for Buying a Replacement Truck Scale on Your Terms
Here is one other scenario that we would like you to think about. Let’s say you have a 25 year old truck scale. It has some weighbridge issues and probably should be replaced. But, you and the scale company talk and decide that some weighbridge repairs could likely be made that might give the scale a little more life. Keep in mind at the same time this talk is taking place, new truck scales are readily available with a short 1 to 2 week lead time for fast delivery.
Well, the truck scale repairs take place and it turns out that you did in fact get an extra year of use out of the scale. Unfortunately, the scale now has more weighbridge issues and repairs will likely not make much sense at this point. And, as often happens, the scale failure has just happened right in the middle of your busiest time of the year! And, now it looks like the lead time on truck scales is closer to 14 weeks and there is a 8% steel surcharge now in place.
This scenario that we just mentioned above is all to real and can very well take place. Sometimes if your scale has lasted for two or three decades, it can be a smart move on your part to setup the replacement purchase on your watch (before the scale actually “breaks”). Maybe you talk with your scale company and decide the next time there is an incentive offered, you’re ready to purchase. This can be a wise decision because we all know that no one wants to be in a situation with a broken scale that must be replaced and then be facing extended downtime and a 14 week lead time before your scale can ship.
There are a variety of options in the truck scale market today and, to the casual observer, initial acquisition price may be the only differentiator. However, manufacturers promising great bargains are able to do so only because they’ve cut corners at some stage of the process—design, materials, components, finish or all of the above. While the price may seem attractive now, the eventual failure of a lower quality truck scale could mean a higher total cost of ownership from extensive downtime, increased maintenance costs, lost revenue and premature replacement.
One other note to mention on the subject of money would be taxes and leasing. This article is not going to be in depth on either of those subjects but if you purchase a new truck scale there can be tax advantages (see IRS section 179). We also have leasing programs which can make it easier to afford a larger purchase like a truck scale.
One other thing we wanted to mention on this subject is the overall trend for truck scale pricing. Generally speaking, the price for new truck scales is not going to get any less expensive in 2021 and beyond. In fact, at the time of this article in early 2021, we have received word from at least (3) truck scale manufacturers that there will likely be surcharges very shortly due to steel prices. (So if you’re in the market for a new scale, it might be time to act now!)
Believe it or not, the goal of this article is not to be completely gloom & doom about repairing a truck scale weighbridge. There are certainly situations where a truck scale overhaul makes sense. Most of the time, it makes more sense to upgrade components and less sense to try and do major weighbridge structural repair.
However, if you’re in the market for refurbishing a truck scale or purchasing a new truck scale… we encourage you to look at the entire picture and get a true understanding of the costs involved and the expected lifespan with each scenario. The fact is that many truck scale manufacturers are getting really good at building their truck scales to fit existing foundations. This can help to lower costs and lessen the down time when you’ll be without a scale.
Truck scales are important to the daily operations of the facilities that use them. That means that selecting a truck scale is an important decision. Whatever scale you choose (or have chosen), will likely be your scale of choice for possibly two or three decades! Often, a little extra thought or cost up front, can pay off down the road with a durable truck scale that can provide decades of service with proper scale maintenance.
If you have questions or would like to obtain a truck scale quote, please complete our RFQ form on our website or you can call our heavy capacity scales team at (919) 776-7737.
Today, most large vehicle scales are installed with above ground or concrete pit foundations. Depending on state or regional requirements, scales can also be installed in a shallow pit, as opposed to the deep pit required by older mechanical scales.
A pit installation requires less space than an above ground scale since longer approaches are generally required for aboveground configurations. However, pit-styles require sump pumps and drains, and are generally more vulnerable to corrosion due to potential standing water.
PROPER SITE PLANNING FOR TRUCK SCALE FOUNDATION
Before we talk about truck scale foundations, it’s important to think about the overall site to make sure we find the perfect location to actually locate the foundation.
To ensure the longest lifespan and best performance for your truck scale, proper site planning is essential. Your truck scale supplier will help you select the best site, considering the traffic flow of your operation, the best location for a foundation, electrical and conduit requirements, soil conditions and drainage, ease of maintenance and accessory locations.
Before purchasing your new truck scale, it may be helpful to draw out a flow map of your current operations and determine if there are any areas for improvement. It is also important to consider future site use when planning. If you expand your site in the future, will the traffic flow and truck scale location still allow for easy operation?
Creating an efficient traffic flow is important to keep operations running smoothly. Be sure there is adequate room around the scale to perform maintenance and to accommodate driver safety. Is there often a waiting line to use your truck scale? Consider the amount of space needed to accommodate a line of trucks, if needed.
Plot out traffic patterns on your flow map, marking where trucks enter the site, load and/or unload material, and exit the site. Make sure there is plenty of room for drivers to maneuver. Take a test drive with a full-size truck around your plotted traffic flow to test for any tight spots or potential safety issues. Note any special filling or dumping that must take place on site to accommodate for the space needed.
Choosing a Truck Scale Foundation Type
Even the toughest scales are put at risk with a poor foundation… Many factors, such as the slope of the site and soil conditions, must be considered prior to construction. The ground must also be free of any settling prior to scale installation. If the foundation is not properly constructed according to the certified drawing provided by your truck scale manufacturer, your truck scale foundation could shift, causing the scale to be outside acceptable calibration tolerance.
Concrete curing periods can vary depending on the type of concrete being used. Work with your scale supplier to integrate the foundation and approach design into your installation and site plan. Your scale supplier should also be able to recommend local contractors with truck scale foundation experience. Of course all of these decisions will be factors in the overall truck scale installation costs.
Above Ground Foundation or Pit Foundation
Until the early 1970s, all truck scales were mechanical and installed in expensive concrete pits. Today, most scales are installed above ground or in concrete pits with floor foundations. With the benefit of new modular construction, scales can also be installed in a shallow pit, as opposed to the deep pit required by older mechanical scales.
One of the biggest reasons for choosing a pit-type installation is space—or lack of it. A pit installation requires less space than an aboveground installation since longer approaches are generally required for aboveground foundations. However, pit-type scales require sump pumps and drains, and are more vulnerable to accelerated rust and corrosion due to the potential of standing water in the pit.
Truck Scale Foundation Designs
Deep Pier Foundation Typical for colder climates such as those found in northern areas of North America, the deep pier foundation places part of the foundation below the frost line to eliminate the negative effects that freeze-thaw conditions can have on foundations. Discuss with your scale supplier if a deep pier foundation meets your application requirements, or if a deep pier or other specific foundation design is required by your state and region. Similar to isolated pier foundations, the deep pier foundation also requires 2,500-3,000 PSF soil bearing pressure.
Shallow Pier Foundation Shallow pier foundations are a cost-effective solution for truck scale sites with adequate soil compaction and a warmer climate that will not encounter frost line issues. Discuss with your scale supplier if a shallow pier foundation is best suited for your application and meets state and regional requirements.
Floating Slab Foundation A full slab foundation is a continuous or monolithic pour of concrete that runs the entire length of the weighbridge. This is the second most cost-effective type of foundation and is designed for ground that has a soil bearing pressure of at least 1,500 PSF. Discuss with your scale supplier if a floating slab foundation is ideal for your application and location, as well as meets state and regional requirements.
Pit Foundation The pit foundation is available in numerous depths, from two to six feet. Your pit depth should best fit your needs as well as adhere to all federal, state and local requirements.
Drainage Away From Truck Scale
One other thing to think about with truck scale foundations is water drainage and avoiding buildup that can collect under the truck scale or excessive water standing in the pit. Efficient water drainage around the foundation is key to preserve scale components. The installation site should have adequate runoff, allowing water to easily drain away from the scale. Areas with heavy rain and melting snow should take extra consideration when planning site drainage.
We sincerely hope that the information contained in this article assists you in your truck scale buying journey. If you need a truck scale quote or purchasing advice, please contact our truck scale sales department by calling (919) 776-7737 or you can complete the Request a Quote form on our website at your convenience.
There’s no question that truck scales are a significant investment for just about any company.
Although a lower-cost truck scale may seem like a more enticing option, the hardware price is only one element of the total cost of a scale.
If you are a potential buyer, then you should be aware of the ways truck scale design, construction techniques, steel content, quality and installation all contribute to the initial price of the scale.
Please don’t hesitate to reach out to us with any questions about explaining truck scale pricing or about additional information or price quotes on the Rice Lake’s SURVIVOR® line of truck scales. Call (919) 776-7737 for more information.
Over the past month, we have layed out in great detail some of the benefits of the Cardinal Armor truck scale.
If you consider one of the aforementioned issues problematic, Cardinal Scale’s ARMOR® digital truck scales can provide the solutions you need.
The ARMOR® provides a great leap forward in truck scale technology. Costly load cell diagnosis, replacement costs, and load cell damage have been greatly reduced due to the ARMOR’s paradigm-changing technology. Carefully consider the following cost factors affecting your bottom line:
If your current scale system lacks remote monitoring, factor in the time and costs spent in trying to diagnose the true failure in the weighing system. Diagnosing a load cell or cable failure can take anywhere from a few hours to a few days… sometimes more. The costs associated with not having your scale in use for that stretch of time can be as expensive as losing a day’s business.
What are the costs associated with constantly having to repair an analog truck scale’s inefficient and delicate wiring system?
What are the labor costs associated with changing a load cell should it fail? Most load cells cost anywhere from $900 to well over $2,000 each… and don’t forget to consider the labor associated with replacing a faulty load cell. Additionally, don’t neglect to factor in the return trip charges associated with having to constantly replace faulty load cells. Return trip charges are a cost that adds up over time and can become a considerable sum.
Replacing the SmartCell® load cell is incredibly simple. Most importantly, it is a very fast procedure that gets your scale back to work in rapid time.
• Ease of use is also continued with installation or replacement of digital load cell (DLC) cards or 225D mainboards in the truck scale’s weight indicator. The 225D indicator can detect whether either option has been replaced using checksums and board identification numbers. The new DLC card or 225D mainboard will be reconfigured to the existing scale by the indicator acknowledging the new card and asking the user to verify if it is new. This simple reconfiguration process saves time and effort.
• One of the most important upgrades the SmartCell® digital load cell offers is the ability for truck scale dealers to change out the load cell in a matter of minutes. Normally, with analog load cells, dealers will have to check, replace, or pull a whole host of wires from the summing box when changing one out. Now, Cardinal’s digital load cells can be removed and replaced in as little as five minutes without any specialized equipment. It really is that short and simple!
• Electronic truck scales with analog load cells require many more moving parts. With an eight-cell system there are up to 100 wires that have to be prepared and terminated, up to 14 configuration jumpers to be set for proper operation, and sense lines must be utilized to regulate excitation voltage. This complicated wiring system lengthens time spent when trying to simply replace a load cell and calibrate it. This cumbersome process is no longer needed with the ARMOR® digital system.
• The ARMOR’s simple load cell connector design and the axis® frictionless centering system’s unique construction permit just a few steps for load cell replacement. After turning off power and jacking up the weighbridge a minimal amount, a single technician simply has to remove the dual load cell cables, remove two bolts that hold the cell to the weighbridge, and place a new load cell in its place. Next, after applying cleaner and Dielectric grease to the load cell cable connectors, the connectors are reconnected, and the load cell bolts are tightened. It’s just that simple—not another moment needs to be spared on time-consuming load cell replacements.
• If you have to spend large amounts of time dealing with wiring analog load cells, the SmartCell® digital load cell streamlines the tedious task of getting your new load cell in operation.
SmartCell® digital load cells provide many layers of protection against damage from water and debris. The SmartCell’s construction, placement, and ingress-blocking technology keep water and grime from damaging the load cells.
• As part of the axis® frictionless centering system that is provided, SmartCell® digital load cells are moved from an exposed area near the ground or beneath the deck to a placement above the bottom of the deck. Generally, most failures that are associated with debris and sediment build-up happen at the base of the truck scale near ground level, which greatly contributes to corrosion. SmartCell® digital load cells are given an extra layer of protection against the filth that typically accumulates under truck scales by being situated much higher in the scale weighbridge
• The orientation of the SmartCell® digital load cells in their load cell stand also provides the added bonus of selfcleaning. SmartCell® load cells rest on top of a cup-and-ball system that grinds up sediment and pollutants that might settle in the receiver cup from day-to-day operations. Normally this accumulation of pollutants would be left to build up and cause issues with load cell integrity or might cause inaccurate readings, but this self-cleaning feature can help protect the load cell modules from incorrect weighing.
• If, by chance, water levels rise high enough to expose SmartCell® digital load cells to moisture, their rating provides the highest level of protection afforded: IP69K. Their stainless steel casing and potting-filled cell body prevents water from entering the load cell and damaging valuable digital components that transmit weighing information.
• SmartCell® load cell cables are also placed above the load cell housing to keep wiring clear of exposure to sediment and water. Load cell cables include rat-proofing protection from nibbling rodents.
Extreme weather and temperatures will cause issues for analog load cells. SmartCell® digital load cells provide the much-needed protection to prevent important internal components from failure.
ARMOR® load cells can operate in a wide range of temperatures. SmartCell® load cells are designed to function at high performance in a wide range of settings. Whether your scale is in an extreme environment or a location that has wildly fluctuating weather, SmartCell® digital load cells provide the stability needed to keep your scale weighing accurately.
SmartCell® digital load cells feature a much more simplified wiring system than an analog truck scale system. Generally, within an analog eightcell scale system there are up to 100 wires that have to be prepared and terminated correctly. Traditional analog wiring systems have several runs of wiring that can be exposed to the normal expansion and contraction caused by temperature fluctuations. SmartCell® digital load cells are connected point-to-point in a “daisy-chain” manner with shielded PVC cables; this reduced total wiring and greater wiring protection lessens the damaging effects of severe heat and cold on the ARMOR® digital truck scale system.
If your scale location is in an area that that experiences load cell and wiring failures due to extreme hot and cold temperatures, SmartCell® digital load cell’s innovative design provides the most protection and return on your investment.
As we discussed in the last entry, the Armor truck scale is a scale worth considering. Today we look at the SmartCell. SmartCell® load cells and iSite software greatly reduce the monetary risks involved in scale ownership.
• Since the circuitry of the load cell is internal, wiring is not openly exposed to corrosion. The internal wiring and digital components are completely protected by Cardinal’s proprietary potting compound process that fills all of the internal voids of the load cell. This load cell technology prevents ingress from moisture and provides the SmartCell® with an IP69K rating. Load cell failures associated with exposure to water and electrical surges are greatly reduced and load cell replacements become much less frequent due to SmartCell® technology.
• Most truck scale manufacturers still offer electronic scales that feature analog load cells. Analog load cells require time-consuming wiring and load cell fault diagnosis. Analog load cells are also much more prone to fluctuations in temperature and wiring degradation and damage due to moisture and sediment. Cardinal’s SmartCell® digital load cells feature stainless steel double-ended shear beam bodies and patent-pending complete internal encapsulation via proprietary potting methods to protect internal circuitry.
SmartCell® load cells are daisy-chained together by waterproof load cell cables and there is no junction box that is susceptible to water and lightning damage. SmartCells can be remotely monitored through Cardinal’s cloud-based iSite portal so dealers can be alerted to a load cell malfunction. Time spent having to randomly diagnose wiring failures is eliminated, and costs associated with lengthy diagnosis periods are also minimized.
• If your scale is to be positioned in a location where chronic downtime is going to be a problem, digital load cells provide the greatest solution to preventing unwanted interruptions and costly load cell repairs and replacements. Lightning-fast load cell diagnosis and quick-and-simple load cell replacement with superior protection create a massive windfall for the end-user that no longer needs to be squandered.