In connection with PROFINET IO and PROFIBUS DP, you can use the following sys- tem functions in the user program:
b DPNRM_DG Read diagnostic data from a DP standard slave (only PROFIBUS DP) b DPRD_DAT Read user data consistently
b DPWR_DAT Write user data consistently b RDREC Read data record
b WRREC Write data record
b RALRM Read additional interrupt information
Fig. 14.8 shows the graphic representation of the function calls.
Common parameters
The parameter LADDR (for DPNRM_DG, DPRD_DAT and DPWR_DAT), ID (for RDREC and WRREC) and F_ID (for RALRM) define the addressed hardware object, for exam- ple a compact DP slave, a module in an IO device, or a transfer area of an intelligent DP slave. The parameters are supplied with the hardware ID. The hardware ID is assigned automatically during configuration and is displayed in the object proper- ties. When programming, you can also select the hardware ID from a drop-down Fig. 14.7 Example of configuration of the transfer areas of an I-slave
menu: Double-click on the supply position in front of the parameter and select the desired object from the drop-down menu, which contains all of the configured rel- evant objects.
Depending on the function, the RECORD parameter defines the source area from which the data to be transferred is read, or the destination area into which the transferred data are written. This can be a symbolically addressed tag or an abso- lutely addressed data area with the format P#[data block.]Operand Data type Num- ber (also see Chapter 4.2.3 “Absolute addressing of an operand area” on page 86).
The source or destination area must be equal in length, as configured for the selected hardware object.
DPNRM_DG Read diagnostic data
DPNRM_DG reads the diagnostic data of a DP standard slave in the format specified in EN 50 170 Volume 2, PROFIBUS. The read procedure is triggered by REQ = “1” and is finished when BUSY signals “0”. The number of read bytes is then present in the function value RET_VAL. Depending on the slave, the diagnostic data is at least 6 bytes and a maximum of 240 bytes long. The first 240 bytes are transferred if the diagnostic data is longer and then the corresponding overflow bit is set in the data.
The LADDR parameter is supplied with the hardware ID of the addressed object. The RECORD parameter defines the area in which the read data is saved.
Note that DPMRM_DG is a system function which operates asynchronously. It must be processed until the BUSY parameter has signal state “0”. RALRM is a system Fig. 14.8 Graphic representation of system blocks for PROFINET IO and PROFIBUS DP
Read data record Write data record Read diagnostic data from a standard slave
Read user data consistently Write user data consistently
Read additional interrupt information
System blocks for PROFINET IO and PROFIBUS DP
block which makes the data available synchronously, i.e. immediately following the call.
DPRD_DAT Read user data consistently
DPRD_DAT reads consistent user data from a DP standard slave or IO device. A CPU 1200 supports 64 bytes of consistent data. Larger areas must be read with DPRD_DAT. This is optional for smaller areas. Areas read with DPRD_DAT must be removed from the cyclic process image update.
The LADDR parameter is supplied with the hardware ID of the addressed object. The RECORD parameter defines the area in which the read data is saved.
DPWR_DAT Write user data consistently
DPWR_DAT writes consistent user data to a DP standard slave or IO device. A CPU 1200 supports 64 bytes of consistent data. Larger areas must be written with DPWR_DAT. This is optional for smaller areas. Areas written with DPRW_DAT must be removed from the cyclic process image update.
The LADDR parameter is supplied with the hardware ID of the addressed object. The RECORD parameter defines the area from which the transferred data is read.
RDREC Read data record
RDREC reads a data record from a module. The ID parameter is supplied with the hardware ID of the addressed object. The RECORD parameter defines the area to which the transferred data is written.
With signal state “1” at the REQ parameter, RDREC reads the data record INDEX from the module and saves it in the destination area RECORD. The MLEN parameter specifies how many bytes are to be read. The assignment of INDEX and MLEN is described in the manual of the respective module.
The transmission can be divided between several program cycles; the BUSY param- eter has signal state “1” during the transmission.
Signal state “1” in the VALID parameter signals that the data record has been read without errors. The LEN parameter then indicates the number of transferred bytes.
In the event of an error, ERROR is set to “1”. Error information is then written to the STATUS parameter.
WRREC Write data record
WRREC writes a data record to a module. The ID parameter is supplied with the hardware ID of the addressed object. The RECORD parameter defines the area from which the data to be transferred is read.
With signal state “1” at the REQ parameter, WRREC writes the data record INDEX from the source area RECORD to the module. The LEN parameter specifies how
many bytes are to be written. The assignment of INDEX and LEN is described in the manual of the respective module.
The transmission can be divided between several program cycles; the BUSY param- eter has signal state “1” during the transmission.
Signal state “1” in the DONE parameter signals that the data record has been writ- ten without errors. In the event of an error, ERROR is set to “1”. Error information is then written to the STATUS parameter.
RALRM Read additional interrupt information
RALRM reads additional alarm information from an alarm-triggering hardware object on PROFINET IO or PROFIBUS DP, for example, from an IO device or a DP slave. It is called in the diagnostic interrupt organization block OB 82 or in a block called within that block. Processing of RALRM is synchronous, i.e. the requested data is available at the output parameters immediately following the call.
The parameter F_ID is supplied with the hardware ID of the addressed object. The assignment of the MODE parameter determines the mode of the system block RALRM. With Mode = 0, RALRM shows you the interrupt-triggering component in the ID parameter; signal state “1” is assigned to NEW. With Mode = 1, all output parameters are written. With Mode = 2, RALRM checks whether the component specified by the F_ID parameter was the interrupt-triggering one. If this applies, the NEW parameter has signal state “1” and all other output parameters are written.
In bytes 0 to 19, the destination area TINFO (task information) contains the com- plete start information of the organization block in which RALRM was called, inde- pendent of the nesting depth in which it was called. Bytes 20 and 21 are filled with the address of the hardware object. Bytes 22 to 31 contain management informa- tion, e.g. the ID number of the PROFINET IO device or the PROFIBUS DP slave.
The destination area AINFO (alarm information) contains the header information and additional interrupt information. The header information for PROFIBUS DP occupies bytes 0 to 3 and, for PROFINET IO, bytes 0 to 25 and contains, for example, the length of the received additional alarm information and the alarm type. The additional alarm information occupies bytes 4 to 223 (for PROFIBUS DP) and bytes 26 to 1431 (for PROFINET IO) and is dependent upon the alarm type.