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PROFIBUS general -- Configuring and programming communication -- Using communication blocks
Transfer of analog values from and to the PROFIBUS DP slave
Which entries deal with consistent data in conjunction with distributed I/O?
How can you access consistent data without SFC14/15 as part of the process image?
Why does my new CPU 315-2DP (Order No: 6ES7 315-2AG10-0AB0) not process the SFC13 correctly?
How do you receive an alarm with the SFB 54 "RALRM" in compliance with DPV1?
DP slave lifelist using SFC51 "RDSYSST" instead of SFC12 "D_ACT_DP"
Can you use the "Signal System Error" function, the FB126 function block and the SFC13 "DPNRM_DG" system function simultaneously?
Notes for the use of the system function SFC12 "D_ACT_DP"
What is consistent data?
How do you read data consistently from a DP standard slave/PROFINET IO device and write it consistently to a DP standard slave/PROFINET IO device?
Disabling DP slaves after startup of the CPU
Diagnostics information of the FB125 with disabled DP slave
Enabling a disabled DP slave with SFC 12 "D_ACT_DP"
Parameter assignment of SFC 103 / SFC 59 required for identifying and reading out topology data
What are the requirements for using the "Prepare cable diagnostics" function?
Notes for the use of the system function SFC12 "D_ACT_DP"
Part number:

QUESTION:
How often can I call the system function SFC12 "D_ACT_DP" at the same time?

ANSWER:
SFC12 "D_ACT_DP" works asynchronously, i.e. this system function executes a task spanning over several cycles. In order to enable the execution of all necessary cycles, the parameter "REQ" has to be set as long as the task is active. The parameter "REQ" needs to stay on "TRUE", until the parameter "BUSY" has reached the "FALSE" level again.

using the S7 300 CPUs with an internal DP interface; the SFC12 can be called up to four times at the same time. The SFC12 can be called up to four times per DP rope (internal and external) at the same time at the S7-400 CPUs.

Note:
When using the CP342-5 as a DP master, SFC12 cannot be used for the activation/deactivation.

Activating a DP-Slave might be costly in time. If you want to abandon a running activation order, start the system function with the same value for LADDR and MODE = 2. Repeat the call with MODE = 2 till the successful abort of the activation task is displayed with RET_VAL. This procedure is only possible with the CPUs of the S7-300 line. You cannot abandon the task with S7 400 CPUs.

Note:
More information about the SFC12 can be found in the manual "SIMATIC System software for S7-300/400 System and Standard functions" at EntryID: 1214574" and in the STEP 7 ONLINE Help (Mark SFC block in the block container and press the F1 key).


 Entry ID:17624225   Date:2003-11-25 
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