Technical data

Table Of Contents
SFBs for Compact CPUs
System Software for S7-300/400 System and Standard Functions - Volume 2/2
28-58
A5E00739858-01
28.11 Receiving and Providing Data (RK 512) with SFB 65
"SERVE_RK"
Description
Use the SFB SERVE_RK (SFB 65) to receive and provide data.
Receiving data: The data are stored in the area that is specified by the partner
in the RK512 message frame header. A call of the SFB is required when the
communication partner executes a "Send Data" (SEND jobs) job.
Providing Data: The data are fetched from the area that is specified by the
partner in the RK512 message frame header. A call of the SFB is required when
the communication partner executes a "Fetch Data" (FETCH jobs) job.
The block is ready to after it is called with the control input EN_R value TRUE. You
can cancel the current transmission by setting the signal status of parameter EN_R
to FALSE. A cancelled job is terminated with an error message (STATUS output).
The input is switched off as long as the signal status of parameter EN_R is set to
FALSE.
In parameter SYNC_DB you declare the DB in which the data that is used by you
in all SFBs for the initialization during startup and synchronization is to be stored.
The DB numbers must be identical for all SFBs in your user program.
To enable the SFB to process the job, you must call it with R(Reset)=FALSE. At
the positive edge on control input R the current transmission is cancelled and the
SFB is reset to basic state. A cancelled job is terminated with an error message
(STATUS output).
For your submodule, you declare the I/O address, which was specified by you in
"HW Config", in LADDR.
NDR is set TRUE if the job was terminated without error, or ERROR is set TRUE if
the job was terminated with an error.
With NDR=TRUE for an SFB call the CPU indicates in the parameters L_TYPE,
L_DBNO and L_OFFSET the area where data were stored or fetched from. Also
shown for a call are the parameters L_CF_BYT and L_CF_BIT and the length LEN
of the respective job.
In STATUS, the CPU indicates an error or, as a result of a warning, the respective
event ID (refer to the appendix).
NDR or ERROR/STATUS are also output (parameter LEN == 16#00) when the
SFB is RESET (R=TRUE).
The binary result BIE is reset if an error has occurred. The status of the binary
result is TRUE if the block was terminated without error.
Note
A parameter check is not included in the SFB. The CPU might go to STOP mode if
the configuration is faulty.