Tech Tips

We regularly receive calls from customers asking us how to reverse the action of the positioner. Follow the simple three-step process below to achieve reversing the action on your positioner. For this Tech Tip, the positioner was originally set to 4mA closed and 20mA. Step 1: Swap tubing of C+ and C- ports. Step 2: Change the Cam Configuration: Remove …

The D400 EX (explosion proof) unit is completely contained in a rugged die-cast aluminum housing. The unit has a unique cover arrangement that allows for simple entry into the calibration/configuration chamber, while not exposing internal components and thus breaking the hazardous area classification. In order to reach the push button chamber, remove the two top screws on the face of …

Note: This tech tip is for when you are mounting a VAC rotary positioner on a linear valve. The V100 and V200 are by nature rotary positioners. To get a rotary positioner such as a V100 or V200 to operate on a linear valve the linear motion of the valve has to be converted to a rotary motion. This is …

Note: This tech tip is for the times when a calibration gets so far out of adjustment that you can’t get the calibration back in to proper range. Reset Zero Turn the zero adjustment (center screw) clockwise, or counter clockwise, until it becomes hard to turn or starts to bind. Once it starts to bind stop turning. Then turn adjustment …

Our team recently put together a document of D400 Push Button instructions: Operating Level Configuration and Parameter Change. We’ve already received great feedback from this resource so we encourage you to check it out! CLICK HERE to download and print a copy (PDF). …

There are many industrial control valve applications that require the valve to stay at the last set point as a failure state. This is frequently called out as Fail Last Position, Fail in Place, or Fail Freeze. These terms are interchangeable, so we will use Fail Freeze for the rest of this article. When specifying a positioner for these applications …

A question that is coming up often as we have more and more customers buying the D400 positioners is, “how difficult is it to install a feedback module into the D400 if it isn’t initially ordered from VAC with the Feedback card already installed?” The answer, it’s very simple. Below you will see a basic instruction sheet that shows that …

One of the most common technical support calls VAC gets on our V100 and V200 is when no input signal or very little input signal is given to the positioner and then the valve package will open. There are 2 possibilities that we need to explore to get our positioner to operate correctly. One is tubing, when we turn on …

Installing gauges onto our V100 or V200 will tremendously help in dealing with any sort of troubleshooting during the life span of the positioner. The importance of the gauge on the “I” Port, by using a 0-30psi gauge, you can trouble shoot most problems with the V100 and V200 series positioners in just a few minutes. When a control signal …

One of the most common technical calls VAC receives is dealing with tubing a positioner for single or double acting applications. The V100 and V200 can be tubed up as double acting or single acting. When the unit is tubed up single acting the C- port needs to be plugged. Remember that on increasing control signal air is always exhausted …

With our V100 and V200 Fail Freeze positioners, users need to be aware that the Fairchild 6100 series Fail Freeze I/P is orientation sensitive. This means that if the positioner is calibrated at one orientation in the shop, and installed in a complete different orientation the zero and span can shift. If this does occur it is a very simple …

Yes, and with our standard C1 cam. Good for three way valves or valves/actuators with slave linkage the standard Cam can also be used for split ranging. Split ranging is when you have two control valves on one input signal and you need one valve to open from 3 to 9psi (4 to 12mA) and the other valve to start …

I receive calls from our distributors and end users about a wide variety of technical and installation questions. Today I would like to focus on one: Installation, Reset and Calibration of the V200 Feedback Unit. A Customer will call saying that the FB unit will not range the full 4 to 20mA, or an error message will appear on the …

Pilot Valve Selection Simplified Selecting the correct pilot valve for your VAC positioner can seem confusing, but a few simple rules will help you pick the correct pilot valve the first time, every time. VAC pilot valves for the V100 and V200 series positioners are selected using 3 factors and 3 basic rules. Selection Factors: Bleed Rate (also called steady …

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 …