Profibus error that no one had looked for
“Even our machine builders were unable to help. The answer was in the message logger.“
THE CHALLENGE
The machine builder replaced everything they could think of. The machine still wouldn’t run.
A food and beverage production site running ELAU PacDrive technology experienced a communication failure between the HMI and the C200 Controller. The site reported the fault to the machine builder – who initially put it down to a corrupted HMI flashcard and a faulty HMI unit.
The machine builder replaced the HMI. Then both flashcards. The machine still failed to run. With parts replaced and no solution in sight, the site was left in an extended unplanned stop – and the machine builder out of ideas.
THE DIAGNOSIS
The fault was in the controller log. It had been there the whole time.
When the DMC engineer arrived on site, PacDriveAssist connected directly to the C200 Controller and opened the message logger – a detailed internal fault record that sits inside the controller and is never surfaced through the standard HMI interface.
The log revealed a repetitive, uncleared error that had been sitting there throughout the fault – and throughout every failed repair attempt: error 4723, “no Profibus configuration data.” Alongside it, a number of cycle-time overrun errors (code 6317) were compounding the communication failure.
The Profibus configuration data was missing – the controller could not establish the communication protocol it needed, and nothing would work until that was resolved. No HMI replacement was ever going to fix it. The fault was in the configuration, not the hardware.
HOW PACDRIVEASSIST SOLVED IT
One connection. Two errors found. Machine running by morning
01 – Connected directly to the C200 Controller
PacDriveAssist logged directly into the C200 – bypassing the HMI entirely. This gave immediate access to the full internal fault log, message history and system state. No hardware changes. No disruption to the existing setup. > Direct controller access – no HMI required.
02 – Identified error 4723 – uncleared Profibus
configuration fault
The message logger showed a repetitive fault that had never been cleared: error 4723, “no Profibus configuration data.” This was the root cause of the communication failure between the HMI and C200. It had been present throughout all previous repair attempts – undetected because no one had accessed the controller log directly. > Root cause confirmed – configuration, not hardware.
03 – Resolved Profibus configuration and cleared cycle-time overruns
With the root cause confirmed, the Profibus configuration was restored and the 4723 error cleared. The cycle-time overrun errors (6317) were also addressed. The DMC engineer remained on site overnight until all faults were resolved and the machine was fully operational – confirmed through PacDriveAssist before handover. > Machine running by morning – overnight resolution How it was solved – at a glance 01 – Connected directly to the C200 Controller Bypassed the HMI entirely. Full internal fault log, message history and system state accessible immediately. No hardware changes required. 02 – Error 4723 found and confirmed as root cause Uncleared Profibus configuration fault sitting in the message logger throughout every repair attempt. Configuration missing – not hardware. Never visible on the HMI. 03 – Configuration restored. Machine running by morning. Profibus configuration restored, 4723 cleared, cycle-time overruns resolved. Engineer remained on site overnight until full operation confirmed. Hardware faults found 0 cause was configuration, not hardware.
WHAT THIS CASE DEMONSTRATES
The fault was never in the hardware. The HMI was a red herring.
his case is a clear example of what happens when diagnosis is limited to what the HMI displays. The machine builder was working from visible symptoms – and replaced everything the HMI pointed to. PacDriveAssist went deeper, directly into the controller, and found the actual cause immediately.
The C200 message logger holds a full record of internal faults – many of which are never displayed on the operator panel. Without direct access to that log, error 4723 was completely invisible. It had been present from the start, sitting uncleared while parts were replaced around it.
This wasn’t a skills gap at the site – it was a tooling gap. The machine builder had access to the same machine but not the same depth of controller data. PacDriveAssist provided access that standard OEM tools and HMI interfaces simply don’t offer.
THE OUTCOME
£29,325 in avoided costs. Machine running by morning. Root cause: a configuration error.
✓ Error 4723 identified – “no Profibus configuration data” – the uncleared fault sitting in the C200 log throughout all repair attempts
✓ Cycle-time overrun errors (6317) also identified and cleared – compounding the communication fault
✓ No hardware faults – the HMI and flashcards replaced by the machine builder were not the cause
✓ Machine operational overnight – DMC engineer remained on site until full resolution confirmed
✓ £29,325 in downtime costs avoided – Total downtime costs avoided £29K Root cause: error 4723 in the C200 message logger.
Not hardware. Not the HMI.
Machine running by morning.
Not hardware. Not the HMI.
Machine running by morning.