PiLogger is OPC client software that connects to any OPC-DA or OPC-UA compliant server, DCS, PLC, SCADA, or historian, and logs high-speed process data for trending, event investigation, and analysis. Built by PiControl Solutions, PiLogger is process control monitoring software that captures PV, setpoint, and controller-output tags at sub-second scan rates, well beyond what a standard plant historian records, so engineers get the fine-grained detail a tuning test, an upset investigation, or a root-cause analysis actually needs.
A plant historian compresses and thins data for long-term storage, which is exactly what makes it a poor tool for tuning analysis and event reconstruction: the fast transient that explains an oscillation or a trip is often the sample the historian smoothed away. PiLogger closes that gap by connecting directly to the OPC server as its own client and logging raw, high-speed tag data before it gets compressed, so the detail survives long enough to diagnose the problem.
The problem: Every DCS and PLC ships with some form of historian or trend display, and for steady-state reporting that is usually enough. It falls short the moment an engineer needs to explain why a loop oscillated, why a batch drifted off-spec, or what happened in the seconds before a trip — the exact moments a compressed, coarsely-scanned historian is least equipped to capture cleanly.
Plant historians use exception and compression algorithms to keep long-term storage costs down. That is the right trade-off for enterprise reporting, and the wrong one for reconstructing a fast transient, because the compression can discard exactly the sample that explains what happened.
A historian sampling once every few seconds cannot resolve a valve stroke, a controller-output kick, or the first few hundred milliseconds of an upset — the detail that separates a tuning problem from a mechanical one.
Watching individual trend displays loop by loop works for one loop at a time, not for reconstructing an event that touched a dozen tags across two units within the same few seconds.
PiLogger removes the gap: it logs raw, high-speed data directly from the OPC server the DCS or PLC already exposes, at scan rates fast enough to catch the transient, with first-out event detection to shortcut the investigation. Data logged in PiLogger exports cleanly to Excel, CSV, or the plant historian for further analysis.
PiLogger's feature set is built for one outcome: high-speed OPC data captured fast enough, and organized clearly enough, to explain what a loop or a plant just did.
Connects as a client to any OPC-DA or OPC-UA compliant server.
No proprietary drivers or new hardware — deploys against the OPC server the plant already runs.
Logs PV, SP, and OUT tags at scan rates down to sub-second resolution.
Captures the fast transient a historian's coarser scan rate misses.
Flags which tag moved first when an alarm or trip condition triggers.
Cuts root-cause investigation from hours of trend-scrubbing to minutes.
Logs dozens of tags in parallel on a single time base.
Supports cross-loop and cross-unit comparison from a single capture.
Starts and stops logging on a threshold, schedule, or manual command.
Keeps log files focused on the event, not hours of steady-state noise.
Exports to CSV, Excel, and common historian formats.
Logged data moves straight into existing reporting and analysis workflows.
Process and control engineers use PiLogger to capture high-speed data before and after tuning changes, verify step tests, and diagnose loop problems flagged by ongoing monitoring. Because PiLogger logs raw OPC data at scan rates a standard historian cannot match, the trend it captures shows the actual closed-loop response, not a compressed approximation of it.
Reliability, operations, and EHS teams use PiLogger's first-out event detection to reconstruct the exact sequence of tag movements after a trip, upset, or safety incident, building a documented evidence trail for investigations and process safety reviews without waiting on a coarser historian export.
For a broader look at PiControl's monitoring and diagnostics software, see the process control monitoring and diagnostics overview.
PiLogger is one part of PiControl's OPC and monitoring software: the high-speed capture tool engineers reach for when a loop needs a closer look than continuous monitoring alone provides.
For continuous, ongoing loop health monitoring rather than point-in-time data capture, APROMON real-time loop monitoring watches PID and APC loops for oscillation, valve degradation, and tuning drift around the clock, ranking loops by economic loss. Engineers often turn to PiLogger for a deep-dive capture on the exact loops APROMON flags.
PiBridge is a dual OPC client that links two different OPC servers across networks, protocols, or sites, useful when the tags PiLogger needs to log live on a different network than the analysis workstation.
PiOPCServer is a simulation OPC server with an embedded PID loop, generating live test data so PiLogger's OPC-DA/OPC-UA client connectivity can be validated and demonstrated before connecting to a live DCS or PLC.
PiLogger logs high-speed OPC data across every sector PiControl serves — each with its own mix of fast loop dynamics, batch events, and trip investigations.
DCS/PLC connectivity, OPC-UA support, scan rates, and how to get a free trial.
See PiLogger connect to a live OPC server, log tags at sub-second resolution, and capture a first-out event. A PiControl engineer will demonstrate the software on data relevant to your plant and discuss free trial software and licensing.
