Tech Tip: Cam Setup

A very important part of calibration of the V100 and V200 is setting the cam properly. If the cam is not set properly the result will be either the positioner will not span out (fail to reach 100% of the range), or the positioner will get full range but the user will not be able to get the positioner to output a linear response to set-point signal. The other issue maybe that the cam nut is not tight causing the positioner to go all the way to span with very little input signal.

Reminder: Before Cam setup, ensure the actuator is in the zero position.

On initial setup of the V100 or V200 it is important to look to see if the cam is set up with the cam tip (3) close to the roller bearing (4) on the positioner. Once the cam nut is tight (1) and set screw tightened (2), put air to the positioner. Then once the air is on, press down on the balance arm. By doing so, we exhaust air to the actuator causing the positioner to move the valve package. When the valve package begins to move the cam will rotate. At this point we can determine if our cam setup is correct. If the cam rotates up and over the cam tip (3) we know the cam must be removed and flipped over. If the cam rotates away from the tip (3) we know that the cam is set correctly.

Product Update: Introducing New VAC I/P

Our engineer has been working hard over the last few years to develop our very own I/P for the V200 series (pictured above right). We have started to receive the first of the new I/Ps in some of our latest shipments and we couldn’t be more excited for this development. The performance of the VAC I/P is better than the older unit used (pictured above left). The sound is a bit different on the VAC I/P since the exhaust of the I/P is located in a different spot than our previous I/P. The bleed rates between the old and new I/P are very comparable. If you have any questions please give us a call  at (205) 678-0507 or email Scott Kratz or Matt Dill.

Benefit of Gauges

When installing a valve positioner it is always recommended that gauges be installed on the positioner.  During normal positioner operation gauges have the benefit of showing air movement between the ports on the positioner and the actuator.  The main benefit of having gauges on a positioner is during calibration.  When a positioner with gauges is calibrated the gauges can be used to determine movement and end of travel of the actuator.   The gauges will indicate when the positioner is loading air into the actuator instead of relying on the change in the sound of the air output or visually noticing the actuator moving.  Another time it is beneficial to have gauges on the positioner is during trouble shooting.  The instrument gauge will determine if the I/P is outputting properly on a electro-pneumatic positioner or if it is receiving a proper signal on a pneumatic positioner.  The output gauges can also help determine if an actuator is leaking.  A positioner with gauges has the benefit of helping to both calibrate and troubleshoot positioners as well as to give a visual indication that the positioner is moving air during normal operation.

Meet Randy Estes


Meet Randy Estes:


Randy began his career as a marketing sales associate at PMV after he graduated from Texas A & M with a degree in Industrial Distribution.  Randy worked at PMV for several years before deciding to move on to Valve Accessories and Controls as the Western Regional Sales Manager in 2004.  Since that time, he has worked tirelessly to grow his territory by seeking out new distributors as well as OEM’s that want to use/sell a better positioner that is supported by far superior customer service than anyone else in the industry.  Over the years, Randy has learned that building a network and getting to know your customers on a personal level is as important as knowing your customers needs on a business level.  While Randy has accomplished many things since he began with VAC 12 years ago, he feels like his greatest accomplishment is playing a crucial role in helping to grow VAC into the company that it is today.  


While he knows that there is a large potential for international sales, he believes that there are many more untapped opportunities for sales right here in the USA.

When he’s not working, Randy enjoys coaching his daughter in the sports that she participates in.  He also enjoys sailing and is a Lacrosse official for the high school and college level in Texas.  

Randy Estes

Valve Accessories and Controls