Structure of the Diagnosis System¶
The AC500 contains a diagnosis system that allows to manage up to 100 error messages in a circular buffer. For each of these events, a time stamp with date and time based on the controller’s real-time clock (RTC) is generated in the runtime system. The time stamp consists of three entries:
- Error occurrence (come)
- Error disappearance (gone)
- Error acknowledgement
If no battery is inserted in the PLC, the PLC clock is set to the following value when switching on the control voltage:
01. January 1970, 00:00
Each error message has a unique error number. This number provides the following information:
- State (come, gone, acknowledged)
- Error class
- Faulty component
- Faulty device
- Faulty module
- Faulty channel
- Error identifier
For a description of the error numbers, please refer to section Organization and structure of error numbers The \ Diagnosis System later in this chapter.
The error numbers are divided into the following error classes:
| Class | Type | Description | Example |
|---|---|---|---|
| E1 | Fatal error | Safe operation of the operating system is no longer ensured. | Checksum error in system Flash, RAM error |
| E2 | Serious error | The operating system works correctly, but the error-free execution of the user program is not ensured. | Checksum error in user Flash, task cycle times exceeded |
| E3 | Light error | It depends on the application whether the user program has to be stopped by the operating system or not. The user decides which reaction is to be done. | Flash memory cannot be programmed, I/O module failed |
| E4 | Warning | Errors that occur on peripheral devices or that will have an effect only in the future. The user decides which reactions are to be done. | Short circuit in an I/O module, battery empty/not installed |
There are different possibilities to access the error messages:
- Diagnosis directly at the PLC by means of “ERR” LED, keypad and display
- Plain-text display of the error messages in the status line of the Control Builder in online mode
- Diagnosis with the PLC browser commands of the Control Builder
- Diagnosis with help of the user program using the diagnosis blocks of the library SysInt_AC500_Vxx.LIB