So you’ve got a draw wire sensor (maybe you call it a string pot, or cable extension). You want to measure how far something moves, and this gadget is just what you need. Sounds easy enough to set up, right? Mount it, pull the cable, plug it in—and done.
Well… if only.
Although it may seem simple, installing a draw wire displacement sensor incorrectly can lead to several annoying problems. So, before you start drilling or wiring, here are five mistakes that occur even with experienced technicians—and how to handle them like a pro.
- Mounting the Sensor on Something That Shakes
It is a classic mistake, and it’s easier to make than you might think. The sensor measures position relative to its position, so if the sensor is mounted on something that moves or vibrates, your readings won’t be accurate. Imagine trying to measure distance with a ruler taped to a shaky table—it just doesn’t work well.
The fix: Mount your sensor on a solid, fixed surface. Use sturdy brackets or a rigid part of your machine frame. Avoid zip ties or any mount that flexes or wobbles. The more stable, the better. - Pulling the Cable at a Wrong Angle
Draw wire sensors must be straight. When you pull the cable at an angle, it rubs and wears unevenly. That’s like pulling on a garden hose bent around a corner — eventually, it’ll get damaged. If you can’t line the sensor perfectly, add a guide to keep that cable moving straight and smooth.
Also, read from our previous blogs- How to Pick the Ideal Draw Wire Encoder for Your Project? - Pulling the Cable Too Far
Every draw wire sensor has a maximum length it can safely measure. Pulling the cable beyond that limit can damage the internal spring or snap the cable entirely. Even pulling it all the way out repeatedly can wear it out faster.
Here’s what to do: Choose a sensor with a bit more range than you actually need. For example, if you need to measure 3 feet, get one rated for 4 or 5 feet to give yourself some guard. Also, if possible, add mechanical stops or limit switches to prevent accidental over-pulling. - Forgetting Where Your Sensor Lives
A sensor meant for a clean, dry lab probably won’t last long if it’s installed outside, in a dusty factory, or near liquids. Check the IP rating of your sensor to make sure it’s protected against dust and water—IP65 or higher is usually a good baseline for industrial environments.
If your environment is harsh—think chemicals, salt spray, extreme temps—look for stainless steel cables and sealed housings. Adding a protective cover or any enclosure is a great option to extend the sensor’s life. - Sloppy Wiring
By this step, you’re almost done, so don’t ruin it up now with rushed wiring. Bad wiring can cause your sensor to give signals or stop working altogether. Use shielded cables, ground everything properly, and follow the instructions carefully. Double-check your connections before flipping the switch.
And test it early—don’t wait until the whole thing is secured to find out something’s wrong. Even if it “just works,” a quick calibration is worth your time. It helps your sensor communicate seamlessly with your system, providing clean, reliable numbers.
Usually, it’s just a simple adjustment.
The bottom line
Proper draw wire sensor installation lets you get accurate measurements for your needs. Beyond that, it extends sensor life and prevents costly downtime. You just need to ensure a few things-
- secure mounting
- straight cable pull
- avoid overextension
- protection from harsh environments
- precise wiring.
These are the key steps for reliable and long-lasting sensor performance. If you want a reliable draw wire displacement sensor, check out BriterEncoder. We’ve got a great selection of tools for different ranges and tough environments. Additionally, getting it online is simple and easy, and if you need help picking the right one for your project, just reach out. Our team will be happy to help!
