The bottom line: Most OEE (Overall Equipment Effectiveness) vendors require expensive industrial middleware to collect cycle data from PLCs. EdgeSense is a Raspberry Pi running .NET 8 that speaks Modbus natively, runs a local touchscreen display, and syncs automatically when the network returns. One less six-figure line item in your implementation budget.

The PLC Integration Problem

Getting cycle data and machine state out of PLCs and into an OEE system has traditionally required expensive middleware that most small and mid-size manufacturers cannot justify.

Traditional PLC Middleware Approach

Industrial IoT middleware: $15,000–$50,000 per installation
OPC-UA (OPC Unified Architecture) gateway hardware: $5,000–$10,000 per line
Proprietary protocol translators for Modbus, Siemens, Allen-Bradley
12–24 week integration and commissioning timeline
Vendor support contracts required for protocol library updates
Offline behavior: data lost during network outage

EdgeSense

Hardware cost: approximately $500 per unit (Raspberry Pi 4 or 5)
Modbus TCP and Modbus RTU native, no translator layer
GPIO (General Purpose Input/Output) direct wiring for cycle counting sensors
Provisioned from a USB drive on first boot, no keyboard or manual setup
Local SQLite queue buffers all data during network outages
Batch sync transmits queued data automatically on reconnect

Cycle Counting and PLC Integration

EdgeSense collects cycle data through multiple input paths to accommodate different machine types and existing electrical infrastructure.

Input Method	How It Works	Typical Use
GPIO Direct Input	Proximity sensor, photoelectric sensor, or PLC digital output wired directly to a GPIO pin. Each rising edge increments the cycle counter.	Stamping presses, injection molding machines, conveyors, assembly stations
Modbus TCP	EdgeSense polls a Modbus TCP register on the PLC at a configurable interval. Register value maps to cycle count or machine state.	Modern PLCs with Ethernet ports (Allen-Bradley CompactLogix, Siemens S7-1200, Mitsubishi iQ-R)
Modbus RTU	RS-485 serial connection to older PLCs or devices without Ethernet. EdgeSense uses a USB-to-RS485 adapter.	Legacy equipment, VFDs (Variable Frequency Drives), older Modicon and AB PLCs
Physical Andon Button (GPIO)	Physical push button wired to GPIO pin. Button press initiates a Downtime (DT) call via the ProAlert API without requiring a mobile device or user login.	Floor-level Andon call initiation where mobile devices are impractical

Local Touchscreen HUD

Each EdgeSense device runs a GTK (GIMP Toolkit)-based local UI on its attached 7-inch touchscreen. Operators at the machine see live production data even when the ProAlert server is temporarily unreachable on the local network.

Asset Status Display

Live asset state (Down, Running, Planned) with active call information. Status updates via SignalR when connected; continues from last known state when offline.

Target vs. Actual Cycles

Target cycle count for the current shift vs. actual counted cycles. Cavity-attributed output display for die-driven manufacturing environments.

Shift Information Panel

Active shift, current production run, product being manufactured, and operator identity displayed on the local screen throughout the shift.

Temporary Fix (Yellow Banner)

Yellow banner alert visible on the local display when a temporary fix is active on this asset. Matches the yellow banner shown in the web and mobile app.

Audio Alerts (SoundEngine)

Audio playback service triggers audible alerts for call events, production warnings, and safety conditions directly from the EdgeSense device.

Production Source Selection

Operators select the active die or tooling on the local touchscreen at run start. Selection drives OEE targets and cavity attribution for the current run.

A Wired Input for Productive State

A physical input flips the asset between productive and idle, which is what drives andon colour and the Availability half of OEE. The machine says whether it is making something, rather than the system inferring it from cycles that may or may not be production.

Offline-Capable Operation

Network interruptions are a reality in manufacturing environments. EdgeSense continues to function and collect data regardless of network connectivity.

Local SQLite Queue

All cycle counts, sensor readings, and events are written to a local SQLite database on the device first. Nothing depends on a successful network transmission to be recorded.
Batch Transmission on Reconnect

When network connectivity is restored, the local queue is transmitted in a batch to the ProAlert server. OEE calculations and production records are updated retroactively with the buffered data.
Counts Keep Moving When the Live Connection Does Not

Cycles are submitted over plain HTTP as well as the live connection, and held in a local queue when neither is reachable, so an outage is replayed rather than lost. Each asset has its own reset epoch, so resetting one machine's counter cannot discard another's cycles, and the device and the server agree on what has been counted.
A Sensor That Was Unplugged Comes Back By Itself

Offline sensors are re-probed rather than written off at boot, and the sensor buffer checkpoints its write-ahead log so a slow checkpoint does not cost readings. An alert records which kind of sensor actually fired, and the sensor display offers a toggle per captured channel, defaulting to the one that raised it.
Real-Time Device Status Visibility

Device online, offline, and syncing states are visible in the ProAlert admin UI and broadcast via SignalR to supervisors. You always know which edge devices are connected and which are operating in local mode.

Provisioning and Device Management

EdgeSense devices are provisioned from a USB drive on first boot. No keyboard, monitor, or network configuration tool is required on the manufacturing floor.

Capability	Details
USB Provisioning	Configuration files placed on a USB drive are read automatically on first boot. The device registers itself with ProAlert, downloads its asset assignment, and begins operating. No IT intervention at the machine.
Device Trust Model	Devices must pass a registration and trust validation process before they are permitted to post data. Untrusted devices cannot inject false cycle counts or call events.
Remote Configuration	GPIO pin assignments, Modbus register maps, and cycle counting parameters are managed from the ProAlert admin UI and pushed to the device over the network.
Workflow Rules Engine	Condition-action rules authored in a visual builder in the browser, with condition and action rows, and stored in the database: when sensor X exceeds threshold Y, trigger action Z. A rule authored in device format is loaded onto the device verbatim rather than being translated on the way through.
Device Events Can Require a Disposition	A rule can say that a device event, a touch pad or a light gate for instance, raises a gap on the daily management board that a named reviewer must disposition before it closes. The rule builder carries the disposition fields, and the pending queue shows what is waiting on whom. A signal from the floor becomes an accountable record rather than a notification nobody owns.
Licence Seats Are Visible	The EdgeSense device page shows seats used against seats bought with a progress bar, and blocks when they run out, so adding the eleventh device to a ten-seat licence is a clear message rather than a silent failure.

ProAlert EdgeSense device management page showing 13 of 20 licences in use across a 15 device fleet, 13 connected and 2 pending, with each device listed by its asset, purpose, firmware version, trust and token state, and time since last heartbeat, including one offline cycle counter that has never checked in — **The fleet, from a desk instead of a ladder.** Cycle counters, machine health monitors and Andon displays in one list, each showing what it is attached to, what firmware it is running, and how long ago it last spoke. The offline drill press counter reading "Never" is the useful row: a device that was pre-registered and never came up looks nothing like one that dropped out, and the page tells them apart without anyone walking the floor.

For IT and OT (Operational Technology) Teams

Component	Technology	Notes
Platform	Raspberry Pi 4 or 5, .NET 8, Raspberry Pi OS	Standard Raspberry Pi hardware available from multiple distributors. .NET 8 runtime runs on 64-bit ARM. No proprietary hardware lock-in.
Server Communication	SignalR WebSocket client (EdgeSenseHub)	Dedicated SignalR hub for IoT device communication to the on-premise ProAlert server. Separate from the main ProAlertHub to prevent edge device telemetry from affecting the primary alert stream.
Local API	Kestrel embedded web server on port 5000	Each EdgeSense device runs a local HTTP API for GPIO configuration and diagnostic access directly from the plant network.
Network Requirements	HTTPS outbound to the ProAlert server	Only outbound HTTPS (port 443) required. No inbound firewall rules. Compatible with NAT and standard enterprise network segmentation. Works through most industrial firewalls.
Local Storage	SQLite on SD card or USB-attached SSD	Data queued locally in SQLite with automatic cleanup after successful sync. Configurable retention period for offline buffer. Industrial-grade SD cards recommended for 24/7 environments.

Connect your machines without a six-figure middleware project.

Book a 30-minute demo... we'll walk through EdgeSense provisioning, cycle counting, and offline sync on actual hardware.

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