Troubleshooting Steps
An unresponsive system is usually a supply, a communications or an interlock problem rather than a failed controller. Work through these checks in order before escalating. They take a few minutes and they resolve the majority of cases.
Safety first
Do not open panel doors or reset a protection device until you know why the system stopped. If anything tripped, treat the plant as capable of restarting until it is proven isolated.
Checks in order
- Power. Confirm the main breaker is closed, the control supply MCB has not tripped, and the supply voltage is within tolerance at the panel, not just at the source.
- Indicators. Look for fault LEDs on the controller, the power supply module and any communications card. A single red LED usually names the problem faster than the HMI does.
- Emergency stops. Check every E-Stop on the system, including remote and field mounted ones. A latched E-Stop in an area nobody visits is a common cause.
- Interlocks. Confirm doors, guards and permissives are made. Many systems will not respond at all rather than reporting a missing permissive.
- Communications. Check link lights at both ends of the affected run. If the HMI is blank but the process is still controlled, the fault is the HMI or its network, not the controller.
- HMI restart. Power cycle the HMI panel only. Do not power cycle the controller, which loses the diagnostic state needed to find the cause.
Before calling support
Have ready: the panel serial number and project reference, the exact text of any alarm, what changed recently including maintenance and firmware work, and an export of the controller event log if you can reach it. Then contact ECS support through the contact page.