Siemens SIMATIC PCS 7 Function Manual page 150

Parameter management
6.1 FB_XXXPA
the "Calculate" button is enabled in the process picture depends on the "CALOP_EN"
parameter of the "FB_XXXPA" block. Recalculation is only performed when "CALOP_EN = 1".
Individual parameters are only calculated with formats 0-5 (INTEGER and REAL).
Once the write job has been processed, the "FB_UA_WM" block writes the confirmation data
(including REQ_ID) to the "UDT_UA_W_ST" input structure of the block and sets the
"QWR_OK" bit.
The input data are only assigned to the block's write job if the ID of the block (REQ_ID in the
output structure) matches the "REQ_ID" of the input structure.
Once the input structure data have been assigned to the write job and the "QWR_OK" bit has
been set, the data are checked for validity and plausibility. The system checks whether the
request data in the input and output structure match.
If the data are plausible and valid, the "WR_OK" output of the "FB_XXXPA" block is set.
A new read job is then triggered and the data are read from the archive that was defined with
the "CALUA_NA" and "CALUA_NO" inputs.
The C function "FB_ReCalcValueByNormPM.fct" is called upon recalculation. This function
recalculates the values.
You can find more detailed information on normalization/recalculation in the section C functions
for normalization/recalculation (Page 160).
The "WR_OK" output is reset when the "L_CAL or OP_CAL" request input is reset.
The "FB_UA_WM" communication block reports any errors it detects during execution of the
write job to the "FB_XXXPA" block. The "FB_XXXPA" block deactivates the write job if an error
occurs ("L_CAL" or "OP_CAL" = 0). This also happens if the "FB_XXXPA" block itself detects
an error.
A positive edge at the "RESET" input resets the "WR_OK" output and the error messages
relating to the write job.
Repetition of jobs
The "COUNT" input value defines how often a job is to be repeated if an error occurs (COUNT
= 0 -> no repetition). Until the specified number of job repetitions has been reached, the job is
reactivated by FB_XXXPA after a wait cycle.
An error message is output after the last repetition.
A new job is only possible if the request signal at the request inputs "PA.REC_REQ", "L_CAL"
or "OP_CAL" is set again.
Whether or not recalculation can be run depends on the "CALOP_EN" bit.
Message box in the faceplate
A message box with user-defined texts can be displayed in the faceplate. These texts can be
created beforehand in multilingual format in the text library. The corresponding text library ID
must then be entered at the "MSBO_NO" input of the "FB_XXXPA" block.
The message box display is controlled using the "MSBO_ACT" input. The message box is
displayed when "MSBO_ACT = 1".
150
Advanced Process Functions (APF)
Function Manual, 07/2016, A5E38719883-AA