Diagnostics are essential to any control system. Costs associated with unplanned downtime means there is intense pressure to fix faults immediately in the event of failure.
Siemens real time diagnostics can help. Whether the downtime is due an I/O card or simply a safety gate not closed correctly, Siemens technology report the cause of faults graphically in realtime via SIMATIC HMI. This enables the diagnosis:
- Without programming knowledge
- Without specialised tools
- Directly via the plant/machince HMI
Most current automation systems provide the capability to diagnose the controller hardware via the programming software. Siemens accelerates this process by allowing the same diagnostics directly on the HMI already connected to the machine.
In this way faults such as I/O card failures, programming errors, bus failures can be diagnosed in real time. Best of all these diagnostics are entirely automatic requiring no extra tools or engineering to implement.
Siemens extends diagnostic capabilities to include process diagnostics.
Process diagnostics are plant-specific and cannot therefore be integrated into the controller hardware or firmware. Process faults are conditions which prevent a machine functioning as expected. Examples include a gate not closed, a material bin empty or material not in position.
Process faults account for 80% of faults during normal operation. Therefore process diagnostics are essential to reduce downtime.
Process diagnostics require diagnostic tools that integrate into the user program, reducing development costs and providing error detection directly via the HMI during normal operation.
Diagnostics without SIMATIC
Without SIMATIC diagnostic functions must be programmed separately from actual control program. Corresponding error messages must also be programmed in the display equipment. As the diagnostics are not automated every possible error condition must be programmed and alarmed. The resulting diagnostics code can easily become as extensive as the control program itself. Any modification to the control program will require reprogramming of the diagnostics.
Process diagnostics for SIMATIC
With SIMATIC you can reduce your downtime through process diagnostics and avoid the engineering overhead
- Simple configuration
Process diagnostics are configured as part of the control program. Critical conditions (eg "Enable start" in the example) are selected to be monitored and the system takes care of the rest
- Automatic change management
Integration of diagnostics into the control program ensures the diagnostics are updated automatically to reflect control program modifications
Error recognition and indication via the HMI unit
Faults are indicated by SIMATIC WinCC SCADA and SIMATIC HMI Panels.
When an error occurs, the precise network or the logical operation that resulted in the error can be displayed. The fault cause is shown as simple ladder diagram, symbol list or as a sequence (eg "Safety_Fence" is shown as the cause below).
Displaying diagnostics on the HMI device accelerates error detection and rectification considerably and requires no programming knowledge or specialised tools.
S7-PDIAG and ProAgent The tools for process diagnostics
S7-PDIAG and ProAgent enable simple engineering of process diagnostics:
- SIMATIC S7-PDIAG
For configuring signal monitoring for process diagnostics. Not required to configure diagnostics in S7-GRAPH or S7-HiGraph
- SIMATIC ProAgent
Runtime software for complete graphical diagnostics via a HMI unit.
Upgrading existing applications of Advanced Real Time Diagnostics:
In existing S7 controllers, process diagnostics can be easily retrofitted. The operands to be monitored are marked and the fault definitions are configured. Changes to the control program are not usually required.