The Thief

I have a friend that owns a bakery. This is not your neighborhood bakery but an industrial bakery that makes cookies for one of the major theme parks in both Los Angeles and Orlando. His facility in Orlando has generated profits since the day it opened, however that is not the case for his Southern California plant. The plants are almost exactly the same, except the California Facility is bigger. The California facility has never generated positive revenue and is being supported by the Florida plant. In fact, last year the California plant lost $1 million dollars. I was blown away by this, and offered to help him find the problem. After a four hour plant inspection/investigation I helped him identify the problem. He had a thief working for him.
The thief wasn’t stealing money, but product. My friend had run production numbers against inventory and stock usage and found that he was bleeding almost 16% of his inventory. He had examined the production records and couldn’t find any discrepancy in units made versus units shipped. His examination of spoilage records found no problems. The problem had to be in the raw ingredients. Was somebody paying kickbacks to a supplier? Was an employee selling materials out the back door?

I found the thief within the first hour of my inspection.

The thief was giving away the ingredients and my friend could not fire him. He couldn’t call the police and have him arrested. He couldn’t even sue the thief and recover any of the stolen money. It was all gone, unrecoverable. Why couldn’t he fire him? Was he a family member or trusted friend? No, my friend couldn’t do anything because the thief was his very own processes.


While performing my inspection I noticed that my friend was checking the weight of every cookie that was made. His customer would not accept cookies that were under weight. As part of my friends quality checks he had purchased a scale that would weigh each cookie as it came off the packing line and reject any cookie that didn’t weigh enough. This type of scale is called an in motion check weigher, and can be set to reject a product that weighs too much or too little. As I watched the machine run, I noticed that all of the cookies were over weight. Not just a small amount, but quite a bit. On a four ounce cookie they were averaging more than a half an ounce over weight per cookie. Soooo, he was giving away over half an ounce per cookie!

Lets get into some detail. His bakery manufactures 7000 cookies a day by hand, and sells them for $4.99 each. When you visit the amusement park you pay $8.99 for one of his cookies. His plant runs five days a week fifty-two weeks a year with twenty days of vacation and holidays, so 240 days a year. His gross revenue on this one product is over $8.3 million a year. Now looking at his production numbers, he was charging $1.25 per ounce. The amount he was actually giving away was $0.79 per cookie. This doesn’t seem like much but he was giving away over $5,500 in potential revenue per day or about $110,000 a month.


He and his production team were so worried about losing their marquee customer that they had made sure that they never sent them an underweight cookie. Just to be sure that it wasn’t underweight, they were making their cookies just a little heavy. Being overcautious had cost my friend $1.3 million dollars in potential revenues. This is of course potential revenue, and doesn’t count production and material costs, but this revenue is gone. The cost of the materials was much less than the selling price of the final product, but adding a level of profit to the ingredients would have generated some amount of gross profit that would have offset his loss to some degree or another.

Many companies look at the services performed by their vendors as pure expense with no way to recover any revenue. This is an erroneous way to look at the relationship. My company Left Coast Scales, services and calibrates weighing equipment. When we find a scale that is out of calibration, we can’t tell how long it has been that way. We can set a limit to the amount of time it was off by looking at the last time we serviced it. The calibration interval is often set by regulatory or customer requirements. But are these intervals good enough for your company? Sometimes they are, but like my friend just having a scale is not enough. It has to be correct. To calculate the daily loss of revenue that can be caused by your scale, use the following formula.

E x N x C = Loss

where E=the amount your scale is off, N=the number of weighments you perform each day, and C=the cost of the ingredient being weighed.

To get the yearly loss multiply the daily loss by the number of work days your company has in a year.
I will give two examples to demonstrate the losses that can occur.

Example 1:
Customer 1 is a recycler and has a truck scale that is off 20 pounds. They purchase scrap steal at $200 per ton or $0.10 per pound. They weigh 10 trucks a day. They work 240 days a year. The state of California requires that the scale be checked once a year.

20 x 10 x $0.10 = $20 per day or $4800 a year

Example 2:
Customer 2 is a cosmetic company and uses a balance to weigh fragrances. The scale is off 0.1 grams. They use a fragrance that they purchase for $2 a gram and weigh out the product 100 times a day for their batching line. They work 220 days a year, and the FDA requires that the scales be checked twice a year.

0.1 x 100 x $2 = $20 a day or $2200 every six months.


My friend had put his company into the position of losing money by justifying to himself that it was better to give away a little product than to lose a customer. Many companies put themselves in this position by not weighing the cost of an inaccurate scale as compared to the cost of regular maintenance. They look at the cost of having a company come out and check their weighing devices and make a decision based on an immediate perception that the service is too expensive. In example #1 the typical scale service on a truck scale is going to be less than a $500 an inspection (depending on where you are located), and the usual error found while performing an inspection is much greater than 20 pounds (when an error is found). In example #2 there are usually many more scales than just the one weighing fragrances, but if that is the only scale being checked the price should be less than $200, and adding extra scales becomes a factor of either time, or price based on the number of devices. Time is based on how long does it take to calibrate all of the scales. My company usually calibrates 4 scales an hour and typical pricing is based on $70 to $140 per hour. Device pricing can vary from $25 a scale to $150 a scale depending on complexity and the company performing the service. Most of the time there is also a travel and equipment charge to get to the site.

When deciding to have your scales calibrated the cost of the inspection and calibration is an important factor, but it should be weighed against the cost of having an inaccurate scale that is stealing money from your business as well as regulatory and customer requirements.
When my friend realized the magnitude of the mistake he was making with his process he had me adjust his check weigher to reject product that weighed too much as well as too little, and sound an alarm when it did. The immediate feedback to his production people helped them with their portions and helped him to bring his production under tighter control.

The Load Cell Went Out and Blew Up Your Indicator

I picked up a customer recently who was tired of the high cost of repairs with their old scale company. It seemed that whenever one of their scales would go down it would have multiple components fail. The load cell, a j-box and the indicator would all go at once. I have only had multi component failures in very few instances and only in severe environmental conditions, like high pressure wash down and immersion or where the scale was abused. I find that when a technician has found multiple failures it is more likely that he is not sure where the problem lies and is throwing everything at it until the problem is fixed. He arrives on site and the scale is drifting. Aha! He thinks it has a bad load cell. He replaces the load cell and it is still drifting. Ok, well it must be the indicator. Now the indicator gets replaced, oh no, the scale is still drifting. Well, it must be the j-card; ah shoot the home run cable is smashed next to the j-box. Well, he got the ok to replace the j-box, might as well replace it as well as put in a new cable. Then he can look good by telling the customer that he’s not going to charge them for the cable. This seems to be a fairly common scenario, because I have heard it many times. I don’t think it is dishonesty that makes it happen; just the technician’s desire to look good in front of his customer and not understanding proper troubleshooting practices. When proper troubleshooting practices are followed the above scenario would not and could not happen.

A technician should always have the tools necessary to trouble shoot the scales he will be working on. To be properly equipped he should have a good load cell simulator, a multimeter capable of reading up to 5000 mΩ or displaying nanoSiemens (nS), a measure of conductance (mΩ = 1000 ÷ nS), a 9 volt battery, and the necessary technical manuals for the equipment. He should also have a thorough grounding in how to use them.

By following the steps outlined below a technician should be able to trouble shoot most scales in a relatively efficient manner. The steps should be followed until the problem is resolved or the problem can’t be found. Many times an intermittent problem will not repeat while you are troubleshooting the scale and everything will appear normal.

It is dangerous for the novice troubleshooter to fall into the trap of familiarity. Just because a problem looks like something you have seen before doesn’t mean the cause of the problem is the same. After a while familiarity will help your troubleshooting but learn to do it correctly first before taking short cuts.

Troubleshooting Steps:

  1. Determine from the operator and/or observation what the problem is. Without a thorough understanding of what is going wrong the technician can spend fruitless time searching for the solution to an imaginary problem. Sometimes the problem lies with customer expectations, and the equipment is incapable of performing the expected task or the customer is not properly trained in the use of the scale.
  2. Thoroughly examine all of the components of the scale noting any discrepancies and deficiencies. For example debris under the scale, the hole in the keypad, the abraded cable, any of these could be the problem or an additional problem that could be confusing the issue further. Next, correct these deficiencies where possible and re-examine the symptoms.
  3. Check the scale setup, dip switches, jumpers and program to ensure that the indicator is set up correctly. The following are real samples of problems that I have seen in the field.
  • The GSE 250/255 has a program soft switch to select 4 or 6 wire load cells. If the unit is set for 6 wire and a 4 wire load cell is used, the scale does not respond to weight.
  • On the old Fairbanks H90-5200, the one that has dip switches. If the dip switches are set incorrectly the scale can display underload/overload or even drift.
  • Several manufacturers have indicators that have a 2mV/V – 3mV/V jumper that can prevent an indicator from going to full scale if set incorrectly. I had one that would weigh perfectly to 72,380 lbs but then stop going up over that weight. I spent hours hunting for that problem.
  • The Mettler Toledo Jaguar/JagXtreme relies on an internal backup battery and when it dies the setup can be completely lost.

Scale controllers have too many variations to list the possible problems in set up, however if the instrument is set up correctly the problem most likely exists on the electrical side.

  1. If the problem is not in the set up of the scale then remove all of the accessories, printers, scoreboards, computers, chart recorders, set point boards, etc…. Any of these accessories could be causing the problem with the scale, through feedback, shorts, miscommunication or numerous other possible ways. If the problem goes away it was in the accessories. Re-connect the accessories one at a time until the problem starts again; once it does you have found your problem component.
  2. If the problem does not go away; put the indicator on a simulator. Check for stability and linearity. The indicator should be stable and by clicking the simulator up and down should repeat and increase and decrease in a linear fashion. If the indicator does not perform correctly then it should be repaired or replaced.
  3. If the indicator passes, the home-run cable should be re-connected, and the simulator should be connected at the j-box. This test is to determine if the home run cable is good. The cable can look fine but still be damaged inside the jacket. If the scale fails and has transient voltage protection (surge voltage protection, SVP) in line with the indicator, bypass the transient voltage protection (SVP), if this works then replace it. If it doesn’t, replace the home run cable and retest the scale.

For Single Load Cell Systems:

  1. Check the wiring at the load cell, perform load cell tests or if possible replace the load cell. If this fixes the problem then it was the load cell. If it doesn’t work go to step number 11.

For Multi Load Cell Systems:

  1. Remove all of the load cells from the J-Box and wire the Load Cell simulator to the J-card and test the test the Indicator for stability and linearity. Does it work? If the indicator doesn’t work replace the J-card and retest it.
  2. If the j-card is good, test the load cells by using the following tests:
  • Tie the signal, excitation, and sense wires together and test their resistance to shield. The resistance should be at least 1000 megohms, or less than 1 nanoSiemen. If it isn’t registering in the correct range then the load cell should be replaced.
  • If the load cell passes the first test, then wire the load cell to an excitation source (A 9 volt battery works fine.) The output of the load cell with no load should be approximately zero. If the load cell can’t be unloaded then you need to know the maximum output of the load cell, for example, a 3 mV/V load cell with 9 volts of excitation would be 27mV. Now a determination must be made to see if the output is above what you would expect and if it is then it needs to be replaced.

** An alternative to the above tests is to re-install the load cells one at a time until the bad load cell is found. This method does not always work due to indicator issues.

  1. After the load cells have been tested and if necessary replaced, the cells need to be re-wired to the j-box and the scale re-evaluated.
  2. Does the scale now work? If it doesn’t work re-evaluate the above tests to make sure they were done correctly. If everything was done correctly and the problem was not resolved call technical support.

Many manufacturers are willing to help you troubleshoot their equipment, because if the equipment can be maintained and repaired it doesn’t get replaced with their competitors. Some of the larger manufacturers will not help because they are trying to protect proprietary knowledge. If you are in a situation where the manufacturer can’t or won’t help, there are several companies that will help if your company has developed a working relationship with them. These companies are the after market repair companies such as National Scale & Control, Debac, RL Ziemba and others. They not only can provide support but often can provide the repair parts for the equipment, which is why they help. Contact them before you need them and find out what they need from you before calling for help. Nobody likes a freeloader and the time they work with you is an investment that they want a payback on.

By following a troubleshooting technique, whether mine or another, your technicians will find the problem faster and more efficiently. This makes for happier customers and less frustrated technicians.