9 access to memory areas of the frequency inverter – NORD Drivesystems BU0550 User Manual
Page 75
3 AWL (Instruction List, IL)
BU 0550 GB-0813
75
3.5.9
Access to memory areas of the frequency inverter
If it is necessary to temporarily save large amounts of data, to hand this data over to other devices or to re-
ceive it from other devices, it is then advisable to use the modules FB_WriteTrace and FB_ReadTrace.
3.5.9.1
Overview of storage modules
Function module
Explanation
FB_WriteTrace
Saves individual data or larger quantities of data
FB_ReadTrace
Reads individual data or larger quantities of data
3.5.9.2
FB_WriteTrace
Individual values or large numbers of values can be temporarily saved in the FI with this FB. The values are
not permanently saved, i.e. the values are lost if the FI is restarted.
If the FB detects a positive flank on ENABLE, all parameters with are present on the input are adopted. The
value which is saved in VALUE is written to the memory address which is labelled by STARTINDEX and
MEMORY. If the writing process is successful, the output VALID is set to 1.
If the FB is now called up several times and the ENABLE input remains at 1, then with each call up of the
FB the input VALUE is read and saved and the memory address is increased by 1. The current memory in-
dex for the next access can be read out under the output ACTINDEX. If the end of the memory is reached,
the output READY changes to 1 and the saving process is stopped. However, if the OVERWRITE input is
set to 1, the memory index is reset to the STARTINDEX and the previously saved values are overwritten.
Values can be saved in INT or DINT format. For INT values only the Low part of the VALUE input is evalu-
ated. The assignment is made via the SIZEinput; a 0 stands for INT and a 1 for DINT values.
The assignment of the memory areas is made via the MEMORY input:
MEMORY = 1 P613[0-251]
corresponds to 504 INT or 252 DINT values
MEMORY = 0 P900[0-247] to P906[0-111] corresponds to 5200 INT or 2600 DINT values
The FB cannot be interrupted by other blocks
With a negative flank on ENABLE all outputs are set to 0 and teh function of the FB is ended.
Table 101 FB_WriteTrace
VAR_INPUT
VAR_OUTPUT
Input
Explanation
Type
Output
Explanation
Type
ENABLE
Execute
BOOL
VALID
Writing process successful
BOOL
SIZE
Memory format
BOOL
FULL
Entire memory is full
BOOL
OVERWRITE
Memory can be overwritten
BOOL
ERROR
the FB has an error
BOOL
MEMORY
Selection of memory area
BYTE
ERRORID
Error code
INT
STARTINDEX
Indicates the memory cell to
be written to
INT
ACTINDEX
Actual memory index, to which sav-
ing will be carried out in the next
cycle
DINT
VALUE
Value to be saved
DINT
ERRORID
Explanation
0
No error
1A00h
STARTINDEX value range exceeded
1A01h
MEMORY value range exceeded