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Getting Started

If I am in the cryogenic field, what controller would I need to read the gauges installed on the vessels?

Our best seller for this application is the Model 100H.  This device includes a Hastings DV-6M thermocouple vacuum gauge tube.  This type of tube is what is most often found permanently installed on cryogenic vacuum jacketed pipes and vessels.  This gauge is often purchased with a carrying case to facilitate mobile use.

I can’t find what I am looking for! Where can I get help?

First, make a list of what range of vacuum you are interested in, with the necessary and or “nice to have” features such as data out and relay controls. Then call us! 732-765-0900.

I need a gauge to test my vacuum pump, what do you recommend?

The 100V is a popular choice.  Typically a rubber stopper will be installed on the gauge tube itself, and this gauge tube/rubber stopper assembly is put on the vacuum pump to test its ultimate suction.  The other unique feature about the 100V is that it is a wide range rough gauge that will measure from 760 Torr (ATM) all the way down to 1 millitorr.  This will allow you to avoid potential problems such as leaky valves and connections.  No other products that employ thermocouple gauge technology can do this.

I need a vacuum gauge that I can take readings on a computer or PLC – what would you recommend?

We can easily meet this requirement by marrying one of our output schemes that most easily integrate with your PLC.  We offer digital RS232, an analog output voltage corresponding to pressure (often called recorder out), Ethernet, and with relay contacts.  Depending on how you want to integrate a vacuum pressure measurement, chances are we have a solution for you.

Which of your gauges reads to .001?

Most of our gauges read in Torr, where the minimum vacuum reading is .001 Torr or 1 millitorr.  Any thermocouple gauges including the model 200, 100V, 100H, 215 and 201 will read .001 at the low pressure end of the range.  These same gauges enable you to read up to 760 Torr (ATM) which will identify potential problems such as leaky valves and connections.  No other products that employ thermocouple gauge technology can do this.

Consult the Conversion Table for a table that compares millitorr, Torr and other pressure units commonly used in vacuum.

What methods of payment are available?

Credit card (Visa, MasterCard, and American Express), pre-approved company check, PayPal, Google checkout, and Bank funds transfer.  The website allows credit card, PayPal and net30 when an approved account exists.

How soon can I have two model 200s?

Model 200s are a stock gauge, and can typically be sent the same day if the order is phoned in by 1pm.

If I need an in-stock gauge, would you be able to send it overnight?

Yes. – Everything can be shipped to arrive first thing next day.

What are the ways to place an order?

Go to first and select your product.  Then, Call us!  We love to hear from you!

Phone: 732-765-0900

Fax to: 732-765-1800

email [email protected]

click through to purchase at

How long do I have until I have to pay my invoice?

You can pay by credit card, or we offer 30 day terms.

Staying Up and Running

How often do I need to calibrate my gauge?

Scientist CalibrationCalibration of a gauge is a decision to be made by the user based on usage, contamination of instrument and procedural obligations. When foreign matter comes in contact with the sensor, it alters the sensor characteristics. Those altered characteristics will yield a different pressure measurement over time.

Calibration frequency is also largely dependent on the type of service your vacuum gauge is used for.

  • In clean, dry environments that are mostly nitrogen, calibration intervals may be extended.
  • In vacuum drying or freeze-drying applications where the gauge is constantly bombarded in water, you may consider calibrating more often.
  • In very dirty environments like heat treating, metalizing and oil purification, there is a likelihood of more frequent calibrations.

Still unsure if your gauges need to be calibrated? Contact us and our vacuum engineer would be glad to help.

How do I define set points?

To set a set point, consult the instruction manual that came with your system.  On the 215 and 201, simply press select, use the up and down arrows to adjust set point 1, and press enter to accept.

I am trying to replace “this gauge”, can you help?

Many of our gauges are designed to replace popular gauges that were used in laboratory and manufacturing equipment.  For example, or 801, 810-2 and DVG-6 are newer redesigned drop in replacement for the original gauges of the same name.

I need to read Vacuum, but also need to control vacuum based on time and temperature… can you help?

A large piece of the DigiVac business is OEM Electronic control.  We’ve made several devices that control a process based on some combination of vacuum, pressure, temperature and state.  In the next several months we will be introducing a vacuum PLC that will enable just that kind of capability in a very cost effective package.

How do you connect a 450D?

Refer to the model 450D manual.  This vacuum regulator works on the principal of downstream control where an internal proportional valve modulates the vacuum path to the vessel.  It works on the principal of a differential pressure sensor.  Set it to zero, and one vessel follows the other vessel.  Set it to another number, and the controlled vessel will be maintained either at a high or lower pressure then the reference vessel.

Can you repair my old 801 gauge?

We can likely repair any old DigiVac vacuum gauge.  They are made from solid state electronics and are very robust.  Call us at 732-765-0900 to obtain a Return Materials Authorization number.  Once the unit is reviewed we will call you with an estimate for the repair before any work is performed.

Can I just buy a new tube?

Yes, you can just buy a new tube.  Make sure you specify which kind of tube you have.  Our most popular tubes are Agilent/Varian type 531, Hastings DV-6M and KJL6000.  We also offer several others.  Let us know what you need.

I need to send in a gauge for calibration/repair, what do I need to do?

Instruments returned for repair or calibration need an RMA number and a completed contamination form.  Call us at 732-765-0900 to obtain an RMA number.  More details can be viewed at our Returns and Services Inquiry page.

Can you make a differential pressure controller?

Yes!  We make differential pressure controllers that measure differential pressure.  An example of this is our 450D differential pressure regulator and our 100LP10H20 gauge.  We have many more – ask if you don’t see what you are looking for.

What is your calibration procedure?

Our calibration procedure involves measuring several vacuum levels and comparing the UUT (unit under test) with the instrument standard, and writing down that data.  For a video of the fun we have calibrating. see below.


Advanced Technical Requirements

How do I measure explosive gas?

Do not use thermocouple technology to measure explosive gasses.  Thermocouple wire filaments can exceed 400 degrees Celsius.  To measure vacuum for explosive gasses and isolated transducer should be used and potentially additional casing depending what environmental requirements exists… for example Class 1 Div 2.

How do I measure gas vapor?

Most of our gauges do just fine in a gas vapor, such as those found in distillations.  Thermocouple technology tends to be quite inexpensive and rugged.  For particularly messy installations, we offer a “siphon tube” to mount between your process and the thermocouple gauge tube to reduce the possibility of contamination.

What is a NIST Calibration?

A NIST calibration is the method and resulting documentation for an instrument  calibrated against a NIST standard instrument where accuracy data is written down to identify traceability back to the National Institute of Standards and Technology (NIST) in Gaithersburg, MD.  Note all vacuum instruments that leave the DigiVac factory are calibrated under real vacuum against a NIST standard. 

How is a NIST Calibration different from a regular calibration?

The only difference between a NIST calibration and a standard DigiVac calibration that is included on all instruments is the inclusion of a paper certificate that identifies the instrument calibration traceable back to NIST standards.

How do I calibrate my model 200?

The model 200 is a wide range gauge. Please refer to the wide range portion of our model 200 instruction manual. 

Model 200, Model 200P and Model 801

What is the accuracy of a model 200 below 25 Torr?

The Accuracy of the model 200 below 10 Torr is +/- 15% or better.  Accuracy from 10-160 Torr is +/- 50%.  For full range accuracy see DigiVac Accuracy.

Can I use a vacuum gauge to regulate vacuum

Yes you can.  You can hook up a valve or a relay that turns a vacuum pump on based on a set point being tripped on a DigiVac instrument equipped with set points (option 2C).  For more information, check out a technical note we have on the subject: Digivac Solution to Controlling Vacuum

How can DigiVac claim better accuracy than the typical stated +/- 15%?

As part of our quality practices, all DigiVac vacuum instrumentation that leaves our factory is calibrated against a NIST standard under real vacuum – no simulation.  We calibrate the whole device with all of its components… the controller, the cable, the sensor and the power supply.  Because we are very diligent about keeping all of the gauges parts together combined with our innovative way of driving our sensors we are able to claim better than the standard +/- 15% accuracy that many instruments based on thermocouple gauge tubes are subject to.

What is the best gauge you have that will read to 1 micron?

For accuracy, either a 201 paired with a 0.1 Torr Capacitance Manometer, or a 201 with a thermocouple card.  The 201 with a thermocouple card does quite well at 1 millitorr and has accuracy through 5 x 10-4.  Most of our gauges read to 1 millitorr including the model 200, 801w, 100V, 100H and 215.

What do I do when my vacuum gauges are all reading differently?

There could be several reasons for this.  First, different technologies react differently to change in vacuum, and some indirect measurement methods (like Pirani, convection and thermocouple) tend to exhibit a hysteresis affect.  A capacitance manometer will respond differently than a thermocouple for example.  Also, one or more of the sensors may be contaminated which may reflect accuracy.  One or of the devices may be placed in a different part of the vacuum system that may have a slightly different pressure, or be closer to a leak or source of vacuum.  And of course something might be broken.  We can help troubleshoot, give us a call.