Siemens TP1200 Comfort HMI Repair - Pharmaceutical, Ankleshwar

A leading pharmaceutical manufacturing facility in Ankleshwar's GIDC industrial estate experienced a critical production line shutdown when their Siemens TP1200 Comfort HMI panel controlling a tablet coating machine became unresponsive.

The 12-inch touch screen exhibited erratic behavior - operators reported that touch inputs were either not registered at all or registered at incorrect coordinates, making it impossible to adjust coating parameters, monitor process variables, or acknowledge alarms.

The HMI displayed intermittent white patches across the screen, and the touch functionality degraded progressively over 48 hours before failing completely during a critical batch run of antibiotic tablets valued at Rs.

The production team attempted basic troubleshooting including system reboots and cable checks, but the touch screen remained non-functional while the display backlight and graphics continued to work normally.

The plant's automation vendor quoted 12-15 days for a replacement panel import from Germany at Rs.

1,10,000, which was unacceptable given the production schedule pressure and regulatory validation requirements.

Upon receiving the Siemens TP1200 panel at our Vadodara facility, our senior HMI repair technician immediately placed it under our high-resolution digital microscope and thermal imaging camera for initial assessment.

Visual inspection revealed no obvious physical damage to the touch screen overlay or display assembly.

We connected the panel to our Siemens TIA Portal diagnostic workstation and confirmed that the internal WinCC Comfort runtime, CPU board, and communication interfaces were functioning perfectly - the issue was isolated to the resistive touch screen digitizer layer.

Using a precision multimeter and oscilloscope, we measured the resistance values across the X and Y coordinate layers of the 4-wire resistive touch screen and discovered abnormally high resistance readings (8.2 kOhms instead of the specified 300-900 Ohms range) on the X-axis layer, indicating delamination or degradation of the transparent conductive coating.

Further investigation using our thermal camera revealed hotspots at three specific points along the flexible printed circuit (FPC) connector where the touch digitizer ribbon cable interfaces with the HMI main board.

We carefully removed the touch screen assembly and discovered micro-cracks in three solder joints on the FPC connector caused by thermal cycling and mechanical stress from repeated touch operations in the high-vibration coating machine environment.