Native MQTT for Allen-Bradley PLCs

Rockwell Automation Allen-Bradley Logix 5000: CompactLogix & ControlLogix

This AOI library adds native MQTT 3.1.1 client functionality directly to Allen-Bradley PLCs — no gateways, PCs, or middleware required.

Publish and subscribe to MQTT topics using standard Logix Add-On Instructions with full support for QoS 0/1/2, authentication, LWT, and automatic reconnect.

✅ Key Benefits

• Native PLC implementation using Ethernet sockets
• No external hardware, OPC servers, or middleware
• Industrial-grade state machines & diagnostics
• JSON payload formatting for time-series data
• Designed for SCADA, IIoT, and cloud integration

🔒 One license per PLC device

⚠️ TCP only (no TLS/SSL)

📦 Included Add-On Instructions (AOIs)

• MQTT_ConnectHandler
• MQTT_MonitorHandler
• MQTT_PublishHandler
• MQTT_SubscriptionHandler
• MQTT_JsonPayloadFormatter

🧠 What Each AOI Does

MQTT_ConnectHandler

• Handles complete MQTT client lifecycle: socket creation, TCP connection, MQTT CONNECT/CONNACK handshake, username/password authentication, LWT, auto-reconnect, keep-alive supervision
• Supports full MQTT 3.1.1, QoS 0/1/2
• Industrial-grade error codes and diagnostics

MQTT_PublishHandler

• Publishes PLC data to MQTT topics with configurable QoS, retain, and duplicate flags
• Designed for cyclic or event-based publishing

MQTT_SubscriptionHandler

• Subscribes/unsubscribes to MQTT topics (wildcards supported)
• Provides subscription state feedback

MQTT_MonitorHandler

• Monitors incoming messages
• Processes only new messages with timestamps, QoS, retain, and duplicate flags

MQTT_JsonPayloadFormatter

• Formats PLC values into compact JSON payloads for dashboards and time-series storage
• Optimized for Telegraf → InfluxDB pipelines

🎁 Bonus Content Included

• Windows 11 IoT Stack Setup Guide (Docker-based)
• Raspberry Pi IoT Stack Setup Guide (Docker-based)

• End-to-end demo architectures, including:
• Allen-Bradley PLC → MQTT → Node-RED → MS SQL → Grafana
• Allen-Bradley PLC → MQTT → Telegraf → InfluxDB → Grafana
• Allen-Bradley PLC → MQTT → Node-RED → Teams / Email / Telegram alerts
• Allen-Bradley PLC ↔ MQTT ↔ FUXA

🎥 Demo Videos Included

See the AOI library in action with real-world, end-to-end examples:

• Importing the AOI library & applying a license & Connecting to an MQTT broker
• PLC ↔ Broker ↔ PLC communication
• Simple setup: PLC → Broker → Telegraf → InfluxDB → Grafana
• Simple dashboard: PLC ↔ Broker ↔ FUXA

📦 Delivered Files & Versions (Current Release)

v1.0.0➡️📄MQTTclientLibrary_Program.L5X

v1.0.0➡️📘 Allen-Bradley MQTT Client Add-On Instructions.pdf

v1.0.0➡️📘 License Activation Guide.html

v1.0.0➡️🚀 Windows 11 IoT Stack Setup Guide.html

v1.0.0➡️🚀 Raspberry Pi IoT Stack Setup Guide.html

v1.0.0➡️🎥 Demo Videos (.mp4)

⚡ Recommended Setup: Standalone PLC Data Aggregation

Use one PLC as a local MQTT aggregator to collect data from multiple source PLCs. Reduces network load, centralizes processing, and keeps your IIoT architecture modular and scalable.

⚡ Quick Start (10–15 Minutes)

1. Import the AOI library into Studio 5000
2. Download the controller to the PLC
3. On first scan, the PLC generates a Request Key
4. Activate the license via the License Dashboard
5. Paste the Response Key into the PLC
6. Configure broker IP, port, and topic
7. Publish your first MQTT message

🔐 Licensing Model (Important)

• One license per PLC device per order
• License is cryptographically bound to the PLC hardware
• License duration is selected via the product variant
• To license another PLC, a new license is required

📘 License Activation Guide (Summary)

1. Retrieve your Payhip Order ID from the invoice
2. Open the License Dashboard
3. Verify Order ID + purchase email
4. Paste the PLC Request Key
5. Generate the License Key
6. Paste it into the PLC Response Key
7. License activates automatically on next scan

PLC License Tags

• mqttClient.License.requestKey
• mqttClient.License.responseKey
• mqttClient.License.licensed
• mqttClient.License.expirationTime (UTC)

🗈 PLC License Behavior (Transparent & Predictable)

• Validation runs only on first scan or when a new response key is entered
• License drops if the controller wall clock time is set backwards
• Adjusting time zone or daylight saving does NOT drop the license
• To reactivate: clear the response key and re-enter the license key

❓ FAQ

Does it work without internet?

Yes. Any local MQTT broker is supported.

Does the license survive power cycles?

Yes.

Can I move the license to another PLC?

No. Licenses are bound to one PLC device.

What happens when the license expires?

MQTT functionality is disabled until a new license is applied.

Is TLS/SSL supported?

No. Use broker-side security or network isolation.

🧪 Tested & Compatible With

• CompactLogix 5370 / 5380
• ControlLogix 5570 / 5580
• Studio 5000 v30+
• Mosquitto, EMQX, HiveMQ
• Standard Rockwell Ethernet modules with socket support

🛠 Technical Notes / Rockwell Compatibility

• Uses native TCP sockets supported on Logix 5000 controllers (QA77472)
• License validation relies on the controller UTC wall clock
• Behavior is consistent with Rockwell’s time synchronization and daylight saving practices

⚙️ Performance (Verified)

Tested on real Allen-Bradley Logix controllers under disconnect/reconnect and publish stress.

• Stable operation across QoS 0/1/2
• QoS 1 & 2 add near-zero overhead
• Performance scales predictably with payload size up to the max (~65KB)

Guidance:

Small telemetry → all PLCs

High-rate / large payloads → ControlLogix 5580

🔒 Security & Privacy

• No PLC logic or source code is uploaded
• License requests are cryptographically verified
• All licenses are device-bound

✔ Summary

• Native MQTT for Allen-Bradley PLCs
• No gateways or middleware required
• Industrial-grade AOIs with demo architectures
• Device-based licensing for one PLC per order
• Bonus IoT stack setup guides and scalable architectures included

🛡️ Legal Notice

Allen-Bradley is a trademark of Rockwell Automation, Inc.

This AOI library is an independent library developed by PLC App Tools and is not affiliated with or endorsed by Rockwell Automation.

📘 License Activation Guide

(Allen-Bradley PLC Add-On Licenses)

This guide explains how to find your Payhip Order ID and activate your license using the License Dashboard.

🔑 Step 1: Get Your Payhip Order ID

Your Order ID is required to activate your license.

1. Open the purchase confirmation email from contact@payhip.com
2. In the email, find the section titled “Need an invoice?”
3. Click Generate
4. Fill in your billing information (any valid info is acceptable)
5. Click Download Invoice
6. Open the downloaded PDF

• At the top of the invoice, locate Reference
• This Reference number is your Payhip Order ID

📌 Keep this Order ID — you will need it to activate your license.

🧾 Step 2: Open the License Dashboard

1. Open your web browser
2. Go to the License Dashboard: link
3. Click Request License in the menu

✅ Step 3: Verify Your Order

1. Enter:

• Payhip Order ID (from the invoice)
• Email address used during purchase

2. Click Verify

If the information is correct, you will proceed to the license request page.

❗ If verification fails:

• Double-check spelling
• Make sure the email matches the Payhip purchase email

🔐 Step 4: Generate Your License Key

1. In your Allen-Bradley PLC, generate a PLC Request Key This key is generated on first scan when no response key exists (mqttClient.License.requestKey)
2. Copy the entire request key
3. Paste it into the PLC Request Key field on the dashboard
4. Click Generate License

⚠️Note: Each order can generate one license per PLC device only. A license is bound to a specific PLC.

The system will securely generate your license.

🎉 Step 5: Apply the License to Your PLC

1. Copy the generated License Key from the dashboard
2. Paste it into your PLC Response Key field (mqttClient.License.responseKey)
3. On the next scan, the PLC will automatically activate the license.

✅ Your license is now active.

mqttClient.License.licensed will now be TRUE.

mqttClient.License.expirationTime will reflect the license’s expiration (UTC).

🔁 Re-Accessing Your License

• If your order was already activated, the dashboard will display your existing license key.
• Each order can generate one license per PLC device.
• To license a different PLC, a new order or additional license is required.

❓ Troubleshooting

Order shows as refunded

→ Refunded orders cannot generate licenses.

License generation failed

→ Ensure:

• The request key is complete
• The PLC date/time is correct
• The request key was generated recently

License expired immediately

→ PLC clock set backwards

• Remove the response key and re-enter the license key

Still stuck?

→ Contact support with:

• Order ID
• Email used for purchase
• Screenshot of the error (if available)

🔒 Security & Privacy

• No PLC logic or source code is uploaded
• License requests are cryptographically verified
• All licenses are bound to your specific device

✔ Summary

1. Get Order ID from Payhip invoice
2. Verify order on License Dashboard
3. Paste PLC Request Key
4. Generate License
5. Activate in PLC

> Important: One license per PLC device per order.

🗈 Notes on PLC Behavior

• License validation and activation is executed only on first scan or when a new response key is entered.
• The license is dropped if the controller wall clock time is changed backwards.
• Adjusting time zone or Daylight Saving does not drop the license.
• To reactivate, simply remove the response key and re-enter it.