Siemens SIMATIC ET 200M Operating Instructions Manual page 259

Hardware interrupt
A hardwareinterrupt is triggered by interrupt-enabled S7-300 modules when a specific event
occurs within the process. The hardware interrupt is reported to the CPU. Depending on the
interrupt priority the associated organization module will be processed.
In SIMATIC S7 / M7: Assigning parameters to a top and bottom threshold, for example,
defines a working range. If the process signal (e.g. temperature) of an analog input module
leaves this working range, the module will trigger a process interrupt (if interrupts are
enabled). The CPU then interrupts the user program or any lower priority classes and starts
processing the process interrupt block (OB 40).
In SIMATIC PCS 7: If the IM 153-2 reports a process interrupt, this means that at least one
data record contains messages concerning time-stamped signal changes or special
messages. The DP master CPU can read and evaluate the data record(s).
In SIMATIC S5: The process interrupt is simulated in the device-specific diagnostics. Cyclic
scanning of the relevant bits in the device-specific diagnostics will enable you to detect
process interrupts, such as upper threshold exceeded.
I&M data
→ Identification and maintenance data
I/O bus
Part of the → S7-300 backplane bus in the automation system. Optimized for rapid signal
exchange between the IM 153-x and the signal modules. The I/O bus is used to transfer
→ user data (such as the signal module's digital input signals) and system data (such as the
signal module's default parameter datasets).
I/O modules, single-channel
A single-channel I/O module scenario means that – unlike redundant I/O modules – the I/O
module is available only once for each process signal. The connection can be unidirectional
or in series.
Identification and maintenance data
Identification data (I data) contain module information some of which is also printed on the
module housing. I data are read-only.
Maintenance data (M data) contain system-specific information, such as location and date of
installation etc. M data are created and written to the module during configuration.
Identification and maintenance data (I&M) are data that are stored in a module for assisting
you in:
● Checking the system configuration
● Locating hardware changes in a system
● Troubleshooting a system
I&M data enable modules to be uniquely identified online.
ET 200M
Operating Instructions, 12/2008, EWA-4NEB780600602-08
Glossary
257