What options are available for Managing MODICON Quantum State RAM
Product Line
Quantum
Environment
Windows 10
Resolution
The Unity Pro LL984 converter analyses the ProWORX32.PWX file (which includes State Ram values)
for Register contents that are not zero. When non-zero values are encountered in contiguous registers,
an Array is created to capture these values, if there are no contiguous registers containing values then
a UINT Variable is created. The Initial values for these converter created variables are set to the value
contained in the State Ram table from the .PWX file.
The variables created have the following naming convention:
- UINT Variable
- _400001_I
- ARRAY[1..2] OF UINT Variable
- _400001_2_I
Note:
- The “I” in the ARRAY VARIABLE NAME indicates the Integer type (UINT)
- The “_2_” in the ARRAY VARIABLE NAME indicates the size of the ARRAY.
General Background regarding Quantum State RAM Behavior
State RAM (%MWx) data is maintained through (Warm Starts) Stop to Run and Power Cycle transitions by the Battery.
State RAM (%Mx) data is handled by configuration setting for Cold Starts.
· Cold Starts always occur following Full Downloads.
· Full Downloads are required after:
o Configuration Changes (not necessarily applicable for CPUs with CCOTF enabled)
o Off-Line Builds (Partial and Full)
The configuration for Cold Start handling is in the CPU Configuration window.
For upgraded projects, it is recommended to evaluate whether or not to CHECK the %MWi reset box.
Checking the %MWi reset box will insure that the Initial Values of the Converter created
variables will be used following any Cold Starts.
Maintaining State RAM long term
As a part of the Unity Upgrade, controller data should be reviewed to determine if the data requires periodic maintenance.
Examples of Data that requires periodic maintenance includes (but is not limited to):
· PID Tuning parameters that may be changed during operation
· Setpoint data that may be changed during operation
· Cumulative Data (Flow Totalizers, Motor Runtime)
There are Unity features for addressing periodic data maintenance, these are:
· Save Data from PLC to File
· Restore Data from File to PLC
· Update Init Values with Current Values
· Update Local Init Values with PLC Init Values
Following are recommendations for the use of these features which should be evaluated.
Released for:Schneider Electric Egypt and North East Africa
