Remote Telemetry Units Vs Programmable Logic Controllers

Programmable Logic Controllers (PLCs) and Remote Telemetry/Terminal Units (RTUs) are two types of devices used for supervisory control and data acquisition (SCADA). They are often used to solve similar problems and talked about interchangeably.

But are they really the same? Is there an advantage to using one over the other? PLCs and RTUs both perform the same basic function: remote alarm monitoring and control of remote equipment. How they go about doing that job, however, varies significantly.

PLCs: Pros and Cons

They have a steep learning curve

PLCs are simple devices; usually a single sensor and a communications interface to output sensor data. They can also be highly customizable. But make no mistake; they have a steep learning curve as they must be individually programmed in order to perform a task. Unless you have a resident PLC coder, you will have to pay an outside expert a lot of money.

Whether you program your PLCs in-house or hire an expert to do it for you, you're looking at a long wait before you're operational. It can take as long as several months just to get everything coded and connected.

How much time can you devote to this project?

Remote monitoring isn't your only job. You have to consider how much time you can devote to programming PLCs and if its worth the effort. Usually, it isn't. What you need is a solution with intelligence built-in that you can quickly get up and running.

PLCs (left) require multiple units to perform different functions and can have hard to use interfaces. RTUs (right) make monitoring simple and D-Wire sensors from DPS can be daisy-chained.

RTUs: Pros and Cons

In most cases, RTUs are a better approach. Here are a few reasons:

1. With an RTU, you can start installing in the morning and be fully operational by the afternoon.
   Many advanced RTUs are simple to connect and some even offer plug 'n' play sensors. An easy-to-use graphical web interface makes it easy to set preferences and connect any other equipment you want to be monitored by the RTU.
2. RTUs are scalable and grow with your network.
   With flexible DNP3/Modbus RTUs, you can always integrate with SCADA in the future as your network evolves. You give up no freedom by choosing RTUs today.
3. RTUs with defined functions almost always have faster tech support for less money - even free.
   With PLCs, there is no programming standard, which leaves lots of room for a programming error. While PLC manufacturers may offer tech support, it's costly and time-consuming because they have to debug code that they didn't write. They don't know what your intent is. With RTUs that come programmed by the manufacturer, the features are standardized. This makes it easy for their tech support to troubleshoot for you, saving you time and money.

Although RTUs have many benefits over PLCs, RTUs' disadvantage is that if you need the freedom to totally program your device, they will not be the best solution. That is because they come pre-programmed from the manufacturer. You can find vertically integrated manufacturers that can build you a perfect-fit solution, but if you have a small local network and want to code your own device, then PLCs might be a better choice for you.

Recommended RTU: The NetGuardian 216

The NetGuardian 216 requires no coding and is up and running almost immediately.

The NetGuardian 216 G3 by DPS Telecom is an advanced RTU that provides all the functionality you need to monitor your operations. The NetGuardian 216 G3 requires no coding and features a simple graphical web browser interface that allows you to set preferences and provision your unit easily. The NetGuardian 216 G3 is also scalable - with the ability to report to up to 2 master stations.

Plus, DPS Tech support is available 24/7 to answer any questions you or your techs may have. Get help directly from the engineers that build the RTUs. They never read from a script and are happy to help you until your RTU is fully operational.

Need more than just some over-the-phone tech support? DPS also offers a factory training course multiple times a year at their headquarters or at a regional location. Get hands-on training from the engineers that build your RTUs.

Be Proactive: Get a Quote

At DPS, we receive many urgent quote requests after an earlier "Do Nothing" decision comes back to bite you. You have no reason not to be proactive (and maybe you'll manage to impress your boss).

Call us. Chat with an expert for 10 minutes. We'll email you a detailed quote with a custom application drawing. We'll even include a summary of business benefits you can use to justify your project budget.

Call 1-800-693-0351 now for your quote or send us a quick online message instead