Function Blocks - FM 458-1 DP
3-1
Edition 03.2003
3 Logic
blocks
3.1 SAV_TR Save FB for NOV_RAM
SAV_TR
input variable
―
R
X
Y
R
―
output variable
mode of operation
―
BO
M
QF
BO
―
no available memory
A REAL type quantity is saved in the NOV-RAM of a technology module.
The function block is a read/write memory for a REAL value. It is only
active, if a 0 at output QF indicates that the memory space in the
NOVRAM is available. The function block operating mode is selected at
input M:
•
The quantity to be saved is entered at input X. It is transferred to
output Y.
•
Further, input quantity X is entered in the NOV-RAM of the module. In
this case, a value, already contained in the NOV-RAM is overwritten.
•
The last input quantity, saved in the
write operating mode
,
is output
at Y.
•
The NOV-RAM is deleted from the operating system each time the
configured software changes (even when the system is configured for
the first time), i.e. zeros are written into it. If the NOV-RAM is then
read, without having previously written a value into the NOV RAM,
then the initialization value of the NOV RAM (zero) is output at Y.
In the INIT operating mode of the function block, memory is made
available to accept a REAL value. Output QF is set to 1 if this is not (no
longer) possible. The function block is then inactive in the RUN operating
mode.
X
Input quantity
(default: 0.0)
M
Operating mode
(default: 0)
Y
Output quantity
(default: 0.0)
QF
No free memory
(default: 0)
Symbol
Brief description
Mode of operation
Write operating
mode (M = 1)
Read operating
mode (M = 0)
INIT Operating
mode
I/O
