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Programming in STEP 7-Micro/Win
8.6 Variable Memory Allocation
The following describes the variable memory allocation.
Variable memory for the library MicroScale
Variable
memory-
Name
Byte
VB n
Actual_Process_Value
VB n+1
Reserved
VW n+2
Process_Value
VB n+4
Bit_Messages
VB n+5
Synchronous_Error_Code
VB n+6
Asynchronous_Error_Bits
VB n+7
Refresh_Counter
VW n+8
Scale_Status_Bits
VB n+10
Select_Process_Value
VB n+11
Command_Code
VB n+12
Bit_Commands
Reserved
VW n+14 Preset_Tare_Value
VW n+16 Lifebit_Counter
VW n+18 Lib_Error_Bits
n = Start byte in variable memory, see library parameter "FirstVB_POINTER"
Table 8-1
SIWAREX MS 8-49
Type
Default
Display, which process value is currently output to position
VW n+2.
0: Gross/Net weight
1: Tare weight
2: Gross process value
3: Net process value
BYTE
B#16#0
4: Tare process value
5: Filtered raw value
6: Unfiltered raw value
To use the process value, the number must correspond with
the definition in position VB n+10. The value that is output to
position VW n+2 only corresponds with the desired selection
in position VB n+10 if the number matches.
INT
0
Reserved
WORD
W#16#0
Current process value
Information on command processing:
Bit0: Command is processed
Bit1: Command processed with no error
BYTE
B#16#0
Bit2: During command processing, an
Bit3...7: Reserve
Synchronous error messages
INT
0
Number of the message if bit 2 was set in variable VB n+4
for one cycle.
Asynchronous error messages
BYTE
B#16#0
Operating error bits Allocation see chapter 7-40
Refresh counter
BYTE
B#16#0
Number of the measurement cycle in the SIWAREX module,
which originates from the current process value.
Scale status
WORD
0
Status bits see chapter 5-32
Current process value selection for the display in position
BYTE
B#16#0
VW n+2:
(see also VB n: "Actual_Process_Value")
Command code
Number of the command that is to be triggered next. Always
INT
0
enter the number of the command first and then trigger the
command (VB n+12, Bit 0).
Bit commands:
Bit 0: Command trigger:
BYTE
B#16#0
Bit is set by the edge, which sets the bit back again
automatically.
Bit 1...7: Reserved
INT
0
Reserved
Preset tare weight
INT
0
This variable is used for defining a "preset" tare weight.
Internal counter to lifebit check
WORD
W#16#0
(Only to be used for library MicroScale)
Error during library processing
WORD
W#16#0
(=Library parameter "SBR_Error_Bits")
Variable memory allocation
Comment
(TRUE for 1 cycle)
error has occurred (=synchronous error)
(TRUE for 1 cycle)
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