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Wireless PressureTrace II Files
PressureTrace II Wireless Software v. 5.0 build 1 - (Released 4/25/08) This is the latest software release for the wireless PressureTrace II systems. This release fixes a BlueTooth driver issue where the program could lock up on some systems if launched without the PressureTrace II module turned on. If your system has not exhibited this problem you do not need to update.
Drivers Drivers Drivers!
Most problems are caused by out of date Bluetooth drivers. Out of date or conflicting drivers can cause myriad problems from loss of connection to program crashes. Check your computer manufacturer's web site for updates to USB and ensure you have current Bluetooth drivers.All Bluetooth 2 dongles should use either the Widcomm drivers from Broadcom or drivers from BlueSoleil. We have noticed several dongle companies do not have the most recent drivers on their web site. If you continue to have problems after installing drivers from the manufacturer's web site check Broadcom and BlueSoleil for the latest drivers.
USB or Serial Models PressureTrace Files
Important Notes About Vista
PressureTrace software versions older then 4.5 were not Vista compliant. If you upgrade your system to Vista the default installation will enable "User Controls". This feature writes hidden files on your system which run instead of files installed in the program files directory. Before you launch any old release on Vista, it is highly recomended you uninstall the PressureTrace software and upgrade to the Vista compliant 4.50 version. Once upgraded to version 4.50 you can enable user controls if you wish.
Gage Installation Videos
Size
37.5 MB
20.5 MB
19.2 MBNote: These files are Microsoft Media Player files and can be played through your browser or
downloaded to your hard drive for use with the Windows Media Player. Right click or (Option click)
the links to download to your hard drive. Strain Gage assemblies no longer appear as pictured in these videos.PressureTrace Common Questions
My PC screen goes blue when I launch PressureTrace II software?
My PC does not have Bluetooth. How can I run PressureTrace II?
My barrel is stainless, does that make a difference?
What causes traces with flat tops?
What changes have been made to PressureTrace?
What power sources can I use to eliminate the batteries?
Can I use PressureTrace for 22 Rim Fire?
After I took a shot all I had was a low level line on the chart.
The PressureTrace program displays "Calibrating" but never displays "Waiting for the shot".
How can I move strain gages to other firearms?
Must the gage be glued to the center area of the chamber?
I already have gages glued on my guns. Do I need to replace the gages I already have?
I own a Savage rifle. Will it work with PressureTrace?
When I enter velocity the bullet exit point always shows remaining pressure. Why is this?
How long should batteries last?
Can PressureTrace software run on old versions of Windows?
Why do some traces looked as if they are delayed? Will increasing the trigger level loose data?
Product Warrantee Issues
What are the known product warrantee issues and how are they fixed?
General Tips
My Laptop screen goes blue when I launch the PressureTrace II software?
When the software launches it immediately searches for the Bluetooth com assignment. Out of date or conflicting drivers can cause a serious Windows crash and "the blue screen of death". First update to the most current version of the PressureTrace II software then check your computer manufacturer's web site to confirm your USB and internal Bluetooth drivers are current. If using a Bluetooth dongle, verify you have the latest drivers at the manufacturer's web site.
All current Bluetooth 2 dongles should use either the Widcomm drivers from Broadcom or drivers from BlueSoleil. We have noticed several dongle companies do not have the most recent drivers on their web site. If you continue to have problems after installing drivers from the dongle manufacturer's web site check Broadcom and BlueSoleil for the latest drivers. The Widcomm/Broadcom driver download is an update and does require installation of the dongle manufacturer's files before updating (see following).
Note On Widcomm Drivers/Cheap Dongles with Pirated Drivers: Early Widcomm drivers have known problems with Windows XP SP 2 and Vista. If your dongle came with Widcomm drivers they must be updated to correct this problem. If the dongle manufacturer shipped product without properly licensing the drivers from Broadcom (owner of Widcomm drivers) the new drivers may not install and there will be no way to make the dongle work. We are not aware of similar licensing issues with the Blue Soleil drivers.
My PC does not have Bluetooth. How can I run PressureTrace II?
If your PC has a USB port all you need is a "Bluetooth Dongle" available on Ebay for as little a 99 cents and most computer stores. It is recommended you buy a Bluetooth 2.0 dongle that does not require special drivers for XP SP2 or Vista. That will ensure you are getting the latest hardware supported directly by Windows. There are also class I and II dongles with different ranges. A class 1 dongle should work to 100 meters. Which ever dongle you buy; you will need to make sure your version of Windows is current, third party drivers from your computer manufacturer are current AND you have the most recent version of drivers for the dongle. If picking one up on Ebay is too risky, try USBGear.com.
My barrel is stainless, does that make a difference?
The documentation for PressureTrace specifies the system "should" be calibrated with a load of known pressure. This is to help ensure pressure calculations are correct even if barrel dimensions are off slightly, the gage is glued slightly "askew" and there are metallurgical differences in the barrel steel.
There are two key numbers used to calculate pressures. They are called Young's Modulus of Elasticity and the Poisson's Ratio.
Young's Modulus of Elasticity: Within the limits of elasticity, the ratio of the linear stress to the linear strain is termed the modulus of elasticity or Young's Modulus and may be written Young's Modulus, or E =(Stress/Strain) It is this property that determines how much a bar will sag under its own weight or under a loading when used as a beam within its limit of proportionality.
Poisson's Ratio: If a square bar is stressed in a testing machine in the direction of its length so that the length increases, there is a contraction in each opposite direction, which produces a decrease in the thickness of the bar. The ratio between the contraction at right angles to a stress and the direct extension is called the Poisson's ratio.
For typical barrel steels the Modulus of Elasticity will fall between 29000 and 30000 ksi with the Poisson's Ratio between .290 and .305. Unfortunately there is no way a shooter can easily determine the metallurgical properties of his barrel. Even the manufacturer may not have accurate values. To be safe and provide reasonable results, PressureTrace uses 30000 ksi for the Modulus of Elasticity and .30 for the Poisson's ratio.
How does this translate?
The most common steels used to make barrels are 4140 Chrome-Moly (around 29700 ksi with P.R. of .290) and 416R Stainless (roughly 29000 ksi with P.R. ranging between .290 and .305).If a Remington 700 30-06 produces a peak pressure of 63254 PSI using PressureTrace; changing the Modulus of Elasticity to 29700 ksi will produce a calculated pressure of 62665 PSI. If a Poisson's Ratio of .29 (instead of .30) is also used for the calculations, the pressure becomes 62323 PSI or for a difference of 931 PSI. This only represents a +/- .75% difference.
For stainless steel barrels, changing the Modulus of Elasticity to 2900 ksi will produce 61292 PSI; or a difference of 1962 PSI. Changing Poisson's Ratio to .29 from .30 will reduce the pressure calculation to 60960 PSI; however, the Poisson's Ratio for stainless can range as high as.305 in which case the difference to be only 1794 PSI or +/- 1.4% difference.
Even the greatest error caused by differing metallurgical barrel properties should be less then normal variations caused by changes to ambient temperature, loading techniques and individual rifle chamber dimensions. Incorrect barrel dimensions or gages not glued perfectly perpendicular to the bore line will produce far greater errors.
For accurate measurement of peak pressure it is always preferred to calibrate the system against a load of known pressure by entering a "correction factor" in barrel data. By doing this all variables relating to the metallurgy of the steel, barrel dimensions and gage installation can be eliminated as potential issues.
If for some reason you would like to change these default values and own a PTII sytem, send email requesting instructions.
What causes traces with flat tops.
If your traces looks like this stop what you are doing immediately.
PressureTrace is designed to work within a range of safe pressures recommended in load manuals or for applications where there is sufficient steel around the chamber to safely contain the pressure. If steel around the chamber expands sufficiently to produce a chopped off trace as shown above you are approaching pressures that may produce a catastrophic failure or after repeated shots permanently swell the chamber. If concerned, email a saved trace file and the voltage conversion number for your module. (The voltage conversion can be found under the "Help/About Pressure Trace" menus and the Tech Info button.)
Most Common Causes:
Large bore muzzle loader using too much powder and/or sabots.
TC Handgun barrels with custom chambers that are too large for the barrel OD.
Light bolt action barrels with a fast taper in front of the receiver that have been re chambered for a longer or larger dia. cartridge.Recoil may disconnect gage plugs if the gage wire is not secured to the fore stock but irregular traces resulting from plug disconnection will not appear flat on top at the same pressure reading for each shot and the right portion of the trace will normally fall to zero pressure.
What changes have been made to PressureTrace?
1) Initial production did not include an external power jack receptacle and required a connection to the 9 volt battery connector inside the battery compartment. If you have already purchased an AC 9 volt battery eliminator you will not need this modification. If you would like your PT module retrofitted with an external power jack, contact Southwest Products.
2) Rocker switches were replaced with LED's mounted directly on the circuit board. This change was made to assist production and avoid damage by government security agencies who may open the enclosure. The change does not significantly alter how the system functions and is not intended to be a new feature. PressureTrace has always employed full hardware handshaking (controlled by the PC software) so the switches were not needed and the new LED indicators duplicate what is displayed on screen by the software. The only advantages are these modules will now automatically power down when disconnected from a PC and the software includes a "sleep" mode to conserve 9 volt battery power.
3) The last production of the original PressureTrace communicated with the PC via USB and had removable cables. In addition to the "hot swappable" feature of USB, this change will eliminate third party driver conflicts that could prevent Windows from opening a com port. The USB PressureTrace hardware drew most of it's power from the PC so the internal 9 volt battery should last up to 10 times longer then earlier designs. For older systems without USB ports and PCMCIA slots USB 2.0 cards are now available for less then RS-232 to USB adapters.
4) PressureTrace II is an entirely new product design. It is housed in a durable Pelican box, has improved power management circuits, 6 AA batteries and communicates with the PC via Bluetooth wireless connectivity.
What power sources can I use to eliminate batteries?
For those systems with an external power jack you can use any common 12 volt AC wall transformer, however some wall transformers have much higher “ripple voltages” than others. A wall transformer with a high ripple voltage may cause electrical noise that will show in traces. If bad enough; poor wall transformers can damage the PressureTrace module. If your traces do not look like those on this web site and have a repeating "saw tooth" shape, you are probably using a noisy power supply.
PressureTrace II is designed so you can also use rechargable batteries.
IMPORTANT:
Before connecting any external power supply to the PressureTrace power jack, make sure the power polarity is correct. The power supply must have 2.1 mm power jack with a positive polarity tip (center pin). If polarity is reversed the module may be damaged.Can I use PressureTrace for 22 Rim Fire?
There are two issues that may prevent PressureTrace from working for 22 Rim Fire or similar low pressure calibers. First, the cartridge chamber is entirely enclosed in the receiver of most firearms so a gage cannot be glued to the barrel over the cartridge. Secondly, the low pressure of a 22 RF is insufficient to expand most barrels, so even if a gage were glued in front of the receiver, the system cannot sense pressure changes.
To use PressureTrace for 22 RF it will be necessary to build a test barrel jig and firing mechanism similar to those used for Piezzo systems. The barrel around the chamber will need to be turned in a lathe thin enough for the metal to expand.
After I took a shot all I had was a low level line on the chart.
1) The PressureTrace module may have triggered on electrical noise. Increase the Triggering Level and try it again.
2) If the trace was of the correct shape (showed pressure rise and fall), but at lower pressure then it should the gage may not be properly glued to the rifle.hile the system is running push down on top of the gage with a finger. If you get a trace by pushing down on the gage it is definitely not properly glued. Remove the gage and clean the barrel with acetone or MEK. If the gage can be removed without damage clean all glue from the underside of the gage with acetone or MEK and re glue the gage.
The PressureTrace program displays "Calibrating" but never displays "Waiting for the shot".
This is most likely due to a problem with the strain gage connection. Check to ensure that the strain gage connector is properly connected to the cable from the PressureTrace module. If you have access to a multi meter check the resistance between the connections to the strain gage. You should read somewhere between 348 to 352 ohms.
The PressureTrace module can be tested as follows:
1. Plug a 350Ω resistor into the end of the cable that runs from the PressureTrace module.
2. Press the [Shoot] button. If the PressureTrace module enters capture mode and works with other strain gages, there is a problem with the strain gage or its connection. If the PressureTrace module does not enter capture mode and does not work with other strain gages, there is a problem with the cable or the unit itself. Contact us to arrange for repair.How can I move strain gages to other firearms?
Moving strain gages is not advised. Removing a gage with acetone will often alter the "gage factor" which is required for proper pressure estimates.
If the gage has been glued to a barrel with epoxy it will certainly be ruined but a gage glued with cyanoacrylic glue may be reusable by applying a "Q" tip wet with acetone to the edges of the gage until it releases. When applied to another barrel the gage MAY work but often seems less sensitive.
Must the gage be glued to the center area of the chamber?
No, and indeed this may not be possible. Attaching gages to the mid region of the chamber is ideal because this is the area of greatest metal expansion with minimal interference from surrounding steel of differing thickness. On some actions chambered for short cartridges you will not be able to glue a gage over this area and will need to glue the gage over the throat.
If the gage is located over the mid point of the main case body and at least 1/4 inch from the shoulder and receiver, pressure readings will be very close to SAAMI results without calibrating the system using a load of known pressure.
If the gage is too close to either the case shoulder or receiver, metal of differing thickness in proximity to the gage will affect expansion of the steel under the gage and therefore alter pressure readings. It is always best to check the system against ammo of known pressure. Most manufacturers will provide pressure information or publish it in their literature. Just be aware the pressure they provide may be the highest pressure expected and measured in a tight-chambered test barrel. The pressure you get in your firearms will often be slightly lower.
SAAMI test protocols specify transducers should be located slightly back from the shoulder and will vary according to the cartridge. European CIP standards measure pressures 25 mm from the bolt face for most cartridges and new NATO standards measure pressure at the case mouth (gage glued over throat area). Location of the strain gage does not significantly affect readings IF the dimensions entered are correct and the gage edges are at least 1/4 inch away from nearby metal of different thickness.
SAAMI CIP You will get useful traces with gages attached anywhere over the cartridge on a solid barrel. No matter where you place the gage adding a calibration factor will adjust readings to match other systems.
I already have gages glued on my guns. Do I need to replace the gages I already have?
PressureTrace uses a standard strain gage although it is smaller than most to fit in tight areas. Connectors and complete gage assemblies with glue are available from our shopping cart. If you have gages already glued to rifles, or wish to buy your own gages you can purchase terminal pads and connector plugs with 4 inch wire leads. Gages should be 350 Ohms, rated to 5 volts and must have a known gage factor (supplied with all strain gages).
We use gages from Micro-Measurements, (1-919-365-3800) part CEA-06-125UN-350. They also have terminal pads (part CPF-75C) which can be used to build your own assemblies.
My double barrel shotgun has a flare near the breech right over the chamber. Will PressureTrace work?
PressureTrace will work on shotguns using the "high resolution" pressure setting (0-2000 PSI). When used with shotguns that have unusual metal shapes over the chamber careful calibration against a factory load of known pressure will be required. Once this is done the system will capture accurate PSI data even if a barrel is not cylindrical over the chamber.
I own a Savage rifle. Will it work with PressureTrace?
Savages with a retaining nut in front of the receiver may make it impossible to glue a gage over the main body of short cartridges. However, gages glued over the throat area will still capture useful information. (See item above regarding gage location.)
How critical are barrel measurements and what is the best way to measure the inside chamber dimension?
Most people will get satisfactory results by simply measuring the diameter of a fired case and adding a couple thousandths of an inch for brass "spring back". A few thousandths off from actual chamber diameter should only represent a couple hundred PSI in most rifle barrels, or an amount well within SAAMI factory ammo standards.
For extreme accuracy a chamber cast can be taken. Cerrosafe (available from Brownells) or even the old armorer's sulfur mix can be used to make a chamber cast. Formulas are available on the reloading tips page.
Another method that works well is to stick a piece of 1" x 1/8" de burred .003"-.005" brass shim stock on the side of a fired case with Super Glue. Put the case in the chamber, and push it forward solidly with the bolt. It will jam before reaching full battery. Insert a cleaning rod down the bore and mark the rod at the muzzle. Remove the rod and case. Place the case on the end of the rod and lay it alongside the barrel. Match the point marked on the rod to the muzzle. Now, mark the case at the midpoint of the strain gauge. Measure the diameter of the casing plus the shim stock. This is your chamber ID at the point where the strain gauge is attached to the barrel.
When I enter velocity the bullet exit point always shows remaining pressure. Why is this?
Even in long barrels there is always some pressure remaining after the bullet exits the muzzle. It would be ideal to have all powder burn completely before the bullet reaches the muzzle but that rarely (if ever) happens in an affective load. Reloaders can only work to minimize muzzle flash but it can never be entirely eliminated. Shoot any firearm at night and the flash you always see is indeed that part of the pressure curve.
How long should batteries last?
Each successive generation of PressureTrace has more efficiently used battery power. The USB PT modules drew most of the power required to run the system through the USB connection so the internal battery lasted up to 10 times longer then earlier RS-232 designs. The original RS-232 modules operated continually from a fresh 9 volt alkaline battery for six to 10 hours. The new PressureTrace II systems are by far the most efficient and the bank of 6 AA batteries should provide sufficient power for up to 130 hours of normal use. With any of the systems the amount of time batteries will last is greatly influenced by the user.
There are three power consumption modes:
Power Off Mode - For original switched units the power switch is off. On switchless RS-232 or USB units the module is disconnected from the PC or the software is not running. In this mode no internal battery power is being consumed.
Quiescent Mode - The PressureTrace module is running, connected to a strain gage and awaiting a command from the software. When the module is in Quiescent mode, the PC software message window will display “Press SHOOT when ready”.
RS-232 - In this mode the module will draw 38 to 40 milliamps from the battery.
USB - In this mode the module will draw approximately 30 milliamps through the USB cable and PC battery. Internal 9 Volt battery usage is negligible only to maintain the USB connection.
BlueTooth - Even without power draw from the PC via USB, the wireless PressureTrace II module only consumes 8 milliamps in this mode.
Capturing Mode - The module has received a command from the software telling it to capture and return pressure traces. When the module is in Capturing mode, the PC software message window will display “BARREL NAME Waiting for a shot”. When you reach the end of a shot string, press the End Shots button on the PC software screen. This will return the module to the Quiescent mode.
RS-232 - In this mode the module will draw 47 to 52 milliamps from the battery.
USB - In this mode the module will draw 14 milliamps from the internal 9 volt battery.
BlueTooth - Bluetooth transfer rates are so quick, despite slightly higher power consumption during transmission, power consumption during this mode is not significantly higher then the USB model.
Can PressureTrace software run on old versions of Windows?
Windows 2000 or newer contains the system files needed to run the PressureTrace II software. Older versions of Windows are no longer supported by Microsoft or compatible with the PressureTrace II software.
Why do some traces looked as if they are delayed? Will increasing the trigger level loose data?
The following trace was taken with the trigger level set to 2. Once you click the shoot button, PressureTrace immediately starts waiting for a shot. To help eliminate false triggers the current resistance through the strain gage must increase to the trigger level and stay above that level for a short time before the system will accept the readings as a valid shot. With the trigger level set to only 2 (as in this example) a slight shot to shot mechanical difference in the action added several microseconds of data to the first shot. We are working on firmware to help synchronize/normalize the peak pressure points but it is extremely difficult and still display true ignition delays.
There are obvious implications to how OBT markers are calculated when this occurs if the start time for a shot is not correct. Increasing the trigger level should not cause loss of data and will help avoid delayed traces caused by mechanical issues in the firearm.
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What makes traces look jagged or "saw toothed"?
PressureTrace regulates current flow but on rare occasions old, used or defective batteries have caused traces with a "saw tooth" appearance. Replacing the battery with a fresh one should eliminate jagged traces. To date every occurrence of this problem has been when using Duracell brand batteries.
PressureTrace is warranted against all defects. If you suspect your system is not working properly email RSI using the links below. For more information about our warrantee policies, click here.
Module Wire Damage - Some users are bending the module cable with sufficient force to break shielding and internal wires. The low capacitance cable is fabricated from quality material and will last indefinitely if it is not abused. When stowing PressureTrace, coil the cable loosely. Do not put kinks or sharp bends in the cable. If you have damaged the module cable contact RSI for repairs.
Loss Of Calibration - Each PressureTrace module is individually calibrated for it's voltage characteristics. Security devices installed to fight terrorism can "zap" computer chipset firmware . In the past this has only been an occassional issue with units shipped outside North America but has recently occurred with units shipped to Alaska and Canada. Here is how to tell if your unit has been "scrogged" by metal detectors or X-ray.
Launch the PT software with the module connected to your PC and the test gage on the end of the gage cable. Push "shoot" and confirm the module calibrates. Click "End Shots". Select the "About PressureTrace" item under the help menu. A window should open with a description of the module; it's firmware, etc. Click the "tech info" button. The window that opens should look something like this. The numbers will vary slightly for each module but should be close to this example. Most importantly the unit gain should be within the range of 800 and 1400, If the unit gain is not within this range or and of the top five items are not close to these, your module will need to be re calibrated.
General Tips
How can I hide the strain gage?
We do not believe encapsulated gages are particularly unsightly or interfere with normal field use, especially when attached to the top of a barrel under a scope bell with excess tape carefully trimmed. Altering the stock of a fine rifle may reduce it's value.
Before making modifications to a stock consider the alternatives. A gage can be applied to the side of a barrel and hidden by the fore stock so only the wire and plug is exposed. Even if this requires removal of some wood, the alteration will not be visible on the exterior of the stock, should not interfere with bedding and will not significantly reduce the rifle's value.
If you wish to alter the stock of your rifle this is the slickest modification we have seen so far. Denton Bramwell made the modification to a rifle he uses regularly for pressure testing. The black cap is just a small hole plug from the hardware store. The white ring is an aluminum spacer, or ferrule, from his electronics junk box. When he wants to capture data, the plug comes out, and the gage leads are available.
The extra gray blob near the gage is JB Weld, serving as a strain relief. (when using our bare gage assemblies this is achieved with a terminal pad) You can see the remains of the green marker he used to identify the area needed for the gage, strain relief blob and coiled wire. While prepping the gun for bedding he used modeling clay over this area to mold a "nice little pocket" into the bedding compound. For this to work the cartridge case must be long enough to allow sufficient room in front of the recoil lug area.
Denton also writes the gage factor on the under side of the barrel...certainly another good idea.
