Siemens Simatic S7-1500R System Manual page 167

Basics of program execution
7.5 Asynchronous instructions
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
Extended instructions
Distributed I/O
RDREC
WRREC
ASI_CTRL
PROFIenergy
PE_START_END
PE_CMD
PE_DS3_Write_ET200
S
PE_WOL
Module parameter assignment
RD_DPAR
RD_DPARA
RD_DPARM
Diagnostics
Get_IM_Data
166
Maximum number of simultaneous jobs for asynchronous extended instructions and low-
er-level instructions used
1513R-1 PN
uses RDREC, WRREC
uses RDREC, WRREC
uses RDREC, WRREC
uses RDREC, WRREC
uses RDREC, WRREC, TUSEND, TURCV, TCON, TDISCON
1515R-2 PN
20
20
10
10
10
10
S7-1500R/H redundant system
System Manual, 10/2018, A5E41814787-AA
1517H-3 PN