Basics of program execution
7.5 Asynchronous instructions
S7-1500R/H redundant system
166
System Manual, 10/2018, A5E41814787-AA
Use of resources
Asynchronous instructions use resources in the CPU during their execution. The resources
are limited depending on the type of CPU and instruction. The CPU can only simultaneously
process a set maximum number of asynchronous instruction jobs. The resources are
available again after a job has been processed successfully or with errors.
Example: For the RDREC instruction, an S7-1500R/H CPU can process up to 20 jobs in
parallel.
If the maximum number of simultaneous jobs for an instruction is exceeded, the following
occurs if another job is started:
●
The job is not executed. The ERROR output parameter returns a value of 1.
●
The STATUS block parameter returns the error code W#16#80C3 (lack of resources).
Note
Lower-level asynchronous instructions
Some asynchronous instructions use one or more lower-level asynchronous instructions for
their processing. This dependence is shown in the tables below.
Please note that each lower-level instruction typically occupies one resource in the
instruction's resource pool.
Extended instructions: maximum number of simultaneously running jobs
Table 7- 6
Maximum number of simultaneous jobs for asynchronous extended instructions and low-
er-level instructions used
Extended instructions
1513R-1 PN
1515R-2 PN
1517H-3 PN
Distributed I/O
RDREC
20
WRREC
20
ASI_CTRL
uses RDREC, WRREC
PROFIenergy
PE_START_END
uses RDREC, WRREC
PE_CMD
uses RDREC, WRREC
PE_DS3_Write_ET200
S
uses RDREC, WRREC
PE_WOL
uses RDREC, WRREC, TUSEND, TURCV, TCON, TDISCON
Module parameter assignment
RD_DPAR
10
RD_DPARA
10
RD_DPARM
10
Diagnostics
Get_IM_Data
10
Summary of Contents for Simatic S7-1500H
Page 1: ......