Side By Side Testing of Trovan^® and Motorola RF/ID Gas Cylinder Tracking Systems

by Jim Broughton, Dataweld Inc.

"Comparison of Read Distances"

In order to compare the read distances of the Trovan® and Motorola transponders, we requested and received from Motorola one of their readers and two different styles of transponders. One transponder is designed for surface mounting on the cylinder. The other transponder fits over the neckring of the cylinder. The Motorola reader provided was the Indala IR-100E. For comparison, the Trovan® GR-68 was used. Similar transponders were used; the Trovan® ID-200, ID-300 and ID-310G. The tests were conducted under ideal conditions. Transponders from both companies were read under the most desirable conditions.

Note: For the comparison the following transponders and readers were used:

1. Diameter of Motorola surface mount tag: 32 mm.

2. Diameter of Trovan® ID-300 tag: 12.8 mm.

3. Diameter of Trovan® ID-200 tag: 25.5 mm.

4. Motorola reader: IR-100E

5. Trovan® reader: GR-68

Relative Performance of Motorola and Trovan® Transponders

The four different comparisons are described below:
A) The Trovan® ID-300 is inserted in the neckring of the cylinder offering an extremely secure method of mounting the transponder. To our knowledge, Trovan, Ltd. is the only transponder manufacturer that can install the transponder in the neckring and still be able to read satisfactorily. In fact, the Trovan® ID-300 mounted in the neckring had over twice the read range of the much larger Motorola transponder mounted on the surface of the cylinder. Surface mounting usually improves read distance.

B) The Trovan® ID-310G is a surface mounted transponder. It is the same as the ID-300 used above, only in a different housing. It is much smaller than the Motorola transponders tested. Surface mounting and size of the transponder improves the readability in most cases, however, the smaller Trovan® ID-310G, surface mounted transponder had three times the read range of the larger Motorola transponder. The diameter of the transponder is significant because typically, the larger the diameter of the transponder, the longer the read range. In all the comparisons made, Motorola transponders had a larger antenna, but shorter read ranges than Trovan® transponders, even when the Trovan® transponders were much smaller. This clearly shows the superiority of the Trovan® design.

C) The Trovan® ID-200 is approximately the size of a quarter ( 25.5 mm in diameter ). The transponder supplied by Motorola for the test was approximately the same size ( 32 mm in diameter ). In this test, both transponders tested were the same size and mounted in the same manner. The Trovan® ID-200 had approximately five times the read range of the Motorola transponder.

D) The final test involved the plastic neckring transponder by Motorola. This transponder is designed to cover the neckring. It also is supposed to provides the ability to read the transponder from any angle. In this test, the Trovan® neckring (countersunk in metal) transponder read up to five times as far at a variety of angles to the cylinder head.  Motorola transponders were also mounted under the cap of an acetylene cylinder but could not be read. Both the Trovan® ID-310G and the ID-200 were placed under the cap and successfully read.

Significance of Read Distances

On the surface, the fact that the Trovan® transponder has a further read distance may not seem significant. But it is. As we discussed during our meeting different types of readers are being developed that enhance productivity. One of these is the walk by reader. Trovan, Ltd. and Dataweld demonstrated a functioning model of a walk by reader in Chicago at the American Welding Society show in Chicago last year. The walk by reader allows the driver to simply roll the cylinders by a stationary reader. He does not have to pick up a reader of any type. This has the potential to greatly speed up the process of loading the truck. With read distances of 1" to 2", as was shown with the Motorola transponder, this type of reader would not be possible. With Trovan® it has already been demonstrated!

Snow has shown to be an issue when trying to read the transponder, making read distance important. When a cylinder has eight inches of snow on the surface, you can not see the transponder. If you have a read range of 1" to 2", you have to basically touch the transponder. This means it will take longer to find the transponder to read it. With the Trovan® transponder this task is greatly simplified because all you have to do is to get within the general range of the transponder. While the Motorola transponders offer some of the benefits of transponders, the read range effectively makes them a "touch tag" type product when used on steel cylinders. The read distance would have a similar impact if the cylinder was covered with: soot, dirt, mud, concrete or other substances.

The reason the Trovan® system has such an advantage in read distance comes from patents involving the design of the transponder and the reader. One of the most significant patents deals with the reader. It will be difficult for other companies to duplicate Trovan®'s success regarding read distance, especially on steel cylinders. The important thing to remember, is that Trovan® already has the best read range in the industry for a transponder on a steel cylinder and is improving it. The rest of the industry at best is playing catch up.

The Bar Code Issue

Another issue to be considered is how quickly the transponders can be read. Tests have been conducted by welding supply distributors that show transponders can be read in an average of three seconds. Bar codes on the other hand take approximately eight seconds. As you process more and more cylinders, this small amount of time can become significant. When you consider how many times a cylinder can be scanned, the seconds add up. First the cylinder is scanned onto the truck, then to the customer, then from the customer, then to the fill line and then back to the dock. The larger the number of cylinders involved the more significant the time issue becomes.

One of the main reasons bar codes take longer to read is that they are very directional. The scanner has to be lined up to read the bar code or it won't read at all. The Trovan® transponder reader, on the other hand, just needs to be in the area of the transponder. If you are working with a pallet of cylinders, a number of them will have bar codes or transponders facing the opposite direction. To read the bar code you would have to position yourself on the other side of the cylinder so you could line up the laser scanner. With the Trovan® transponder this is not required.

Bar codes also have a short life span. The consensus in the industry is that two years is a long time for a bar code to last. Then you begin replacing them. In some cases, the bar codes have to be replaced each time the cylinder is returned. The Trovan® transponder, on the other hand, has been laboratory tested using accelerated life testing. The results showed that you could reasonably expect more than twenty years out of the transponder. Allied Signal found this to be true and began installing the Trovan® ID-310G. The labor costs associated with replacing the bar code can quickly outweigh the initial advantage offered by the lower cost of the bar code. Studies have shown that at three years, the transponder begins to have a price advantage because it is not constantly being replaced like the bar code.

This constant replacement of bar codes, creates other problems. First there is the overhead associated with replacing the bar code. When the bar code does not read, the driver must enter the cylinder number manually. This takes longer, increasing your labor costs. It also creates an opportunity for errors and headaches.