Siemens Simatic S7 Series System Manual

Program instructions
7.10 Interrupt
S7-200 SMART
282 System Manual, 09/2015, A5E03822230-AC
Offset
Field
Format
Type
Description
32 Previous process variable
(PV
n-1
)
REAL In/Out Contains the value of the process variable stored
from the last execution of the PID instruction.
36 to 79 Reserved for auto-tuning variables. Refer to PID loop definition table (Page 468) for details.
7.10
Interrupt
7.10.1
Interrupt instructions
When you make the transition to RUN mode, interrupts are initially disabled. In RUN mode,
you can enable interrupt processing by executing the ENI (enable Interrupt) instruction.
Executing the DISI (disable interrupt) instruction inhibits the processing of interrupts;
however, active interrupt events will continue to be queued.
ENI, DISI, and CRETI
LAD
FBD
STL
Description
ENI
The enable interrupt instruction globally enables processing of all attached inter-
rupt events.
DISI
The disable interrupt instruction globally disables processing of all interrupt
events.
CRETI
The conditional return from interrupt instruction can be used to return from an
interrupt, based upon the condition of the preceding program logic.
Non-fatal errors with ENO = 0
SM bits affected
• 0004H Attempted ENI or DISI exe-
cution disallowed in an interrupt
routine
None

Siemens Simatic S7 Series Specifications

General

CPU	Varies by model (e.g., S7-300, S7-400, S7-1200, S7-1500)
Communication Interfaces	PROFIBUS, PROFINET, Ethernet, MPI
Programming	TIA Portal, STEP 7
Programming Languages	LAD, FBD, STL, SCL, GRAPH
I/O Modules	Digital, Analog, Specialty modules available
Operating Temperature	0°C to 60°C (standard models)
Mounting	DIN rail mounting
Operating Voltage	24V DC or 120/230V AC (varies by model)
Protection Class	IP20 (standard models)
Memory	Varies depending on the S7 model. Includes work memory (RAM) for program execution, load memory (EEPROM or Flash) for program storage, and system memory for operating system functions. Memory sizes range from kilobytes to megabytes.