Industrial Networking Rants and Insulation Tester Tips

This week, we covered several great questions from the community, ranging from practical tool tips to high-level networking debates.

The "Lock" Button on Insulation Testers

A viewer pointed out a helpful feature regarding insulation testers that I initially overlooked. When using the insulation mode, you typically have to press and hold the test button. However, most modern testers have a "Lock" button.

Engaging the lock allows the tester to run continuously without you holding the button. This makes the tool significantly more useful because you can swap the probes for alligator clips and perform hands-free testing. Just remember to prioritize safety when the device is in this active mode.

Keyhole Nibblers vs. Stainless Steel

We received a question asking if the Greenlee keyhole nibbler, which I reviewed recently, works on stainless steel panels.

The short answer is no. While I have attempted to use it on stainless steel, the experience was poor. Stainless steel is much harder than mild steel, making the initial drilling process difficult. Furthermore, the force required to cut caused the panel to flex significantly. For stainless steel enclosures, you are better off using a hydraulic punch or having the holes laser-cut.

The Debate: Explicit vs. Implicit Messaging

There was a lively discussion in the comments regarding Read/Write messages (Explicit) versus Produced and Consumed tags (Implicit).

A common misconception is that you should always use Produced and Consumed tags if you are on a CompactLogix or ControlLogix system. While these tags are efficient for high-speed, real-time control, they broadcast data at a set interval (e.g., every 20 milliseconds).

If you have data that only changes once a day or once a week, sending it every 20 milliseconds wastes bandwidth. As networks grow, this unnecessary traffic can cause congestion.

• Implicit Messaging (Produced/Consumed): Best for critical, high-speed data that changes constantly.

• Explicit Messaging (MSG Instructions): Best for data that changes infrequently or does not require real-time updates.

A well-optimized system often uses a mix of both.