RTA's Blog
Stop Wasting ControlLogix Slots: A Smarter Way to Ingest ASCII Data
Dec
An Efficient and Effective Alternative to the MVI56E-GSC or 5069-SERIAL
Summary: To ingest ASCII data from barcode scanners or weigh scales into a Rockwell ControlLogix and CompactLogix PLC, engineers traditionally use in-rack modules. However, an external EtherNet/IP to ASCII gateway like the RTA 435NBX is often more efficient because it writes directly to controller tags, eliminating the need for complex ladder logic parsing.
Why send ASCII data to an Allen-Bradley ControlLogix and CompactLogix?
The world is not binary and PLC applications will always require data from serial streams. You have a job to do; do it efficiently and effectively. An external gateway is the best solution for applications such as:
- Connecting barcode scanners to ControlLogix
- Integrating RS232 devices to EtherNet/IP tags
- Moving weigh scale data into Studio 5000
- Making meters look like EtherNet/IP Adapters
What Are the Advantages of an ASCII to Logix PLC Gateway?
If you’ve ever struggled to configure a MVI56E-GSC module or the 5069-SERIAL module, you know that “In-Rack” doesn’t always mean “Easy.” Between managing the I/O tree and handling complex backplane buffers, a simple barcode string can become a multi-hour integration project.
The RTA 435NBX moves the complexity out of the chassis and into an intelligent, standalone gateway that:
1. Preserves Your Chassis Real Estate
In-rack modules are expensive “slot-hogs.”
- Zero-Slot Footprint: Why buy an expansion chassis just to add a single weigh scale? The 435NBX mounts on a DIN rail and connects via your existing Ethernet switch.
- Universal Compatibility: Unlike in-rack modules that are specific to ControlLogix or POINT I/O, one RTA gateway works across your entire fleet, from legacy L61s to the latest L85E processors.
2. Doesn’t Require Adding to the I/O Tree or AOP Required
- Adding a module to the I/O tree usually requires a PLC download. or navigating a finicky Add-On Profile (AOP).
- Non-Invasive Integration: The 435NBX operates as a “Tag Client.” It writes data directly into your existing Controller Tags.
- No Firmware Matching: You’ll never have to worry about the module firmware being incompatible with your CPU’s major revision.
3. Provides Pre-Parsed Data vs. Raw Buffers
- In-rack modules often dump a raw, messy buffer into your tags, leaving you to write ladder logic to find the “start” and “end” of your data.
- Logic-Free Parsing: Use our browser-based tool to strip delimiters and extract only the values you need (e.g., converting a portion of a raw string, “Total of 356 Parts”, into a REAL or INT tag with a value of 356).
- Immediate Availability: By the time the data reaches the PLC, it’s already formatted and ready for your process logic. No COP or CPS instructions required.
4. Offers Simplified Maintenance & Troubleshooting
- When an in-rack module fails, you’re often looking at a “Module Faulted” LED and a trip into the Studio 5000 diagnostic tab.
- Browser Diagnostics: View the live serial stream directly in your web browser. You can see exactly what the barcode scanner sends without getting access to the PLC. before it ever hits the PLC.
- Hot-Swappable: If a gateway needs to be replaced, you don’t have to power down the chassis or disrupt the local I/O backplane.
| Feature | A-B In-Rack Module | ASCII to PLC Gateway |
|---|---|---|
| Physical Space | Consumes a Chassis/Rack slot | Din-rail Mounted (External) |
| Configuration | RSLogix/Studio 5000 I/O Tree | Simple Web Browser |
| Data Delivery | Buffered (Requires Parsing) | Direct to Tag (Pre-parsed) |
What is the Real Cost of an ASCII to PLC gateway?
Deployment time, not the list price, is the real cost of an ASCII to ControlLogix and CompactLogix gateway. An external gateway can be writing weigh scale values into your data table before you can even power down and install the 5069-SERIAL.
How Does a Preconfigured ASCII to Logix PLC gateway reduce deployment time?
A scale provider had RTA preconfigure its gateway. Whenever it needs to move weigh scale values to a ControlLogix or a CompactLogix, they drop in a ready-to-run gateway, saving hours of deployment time compared to an equivalent rack mounted solution.
Conclusion & Next Steps
You have better things to do than write serial drivers or struggle with inflexible rack-mounted solutions. Stop treating ASCII like I/O and start treating it like data. Let the RTA serial to ControlLogix and CompactLogix gateway do the heavy lifting.
Ready to reclaim your chassis slots? View the technical specs on the 435NBX ASCII to PLC Gateway or contact an Enginerd™ application engineer at 262-436-9299 or solutions@rtautomation.com.
