Beckhoff Embedded PC NOV/DP-RAM Function Block

      Embedded PC NV-RAM Data Backup Function Reference

Purpuse

Improve generic NOV/DP-RAM direct link to PLC variable，reduce system load & improve real time capability。

VAR_INPUT

     bDataInit : BOOL := TRUE; (* Reload Data From NV RAM Request Must Execute Once Before Execute bBackupExecute *)

     bBackupExcute : BOOL := TRUE; (* Cycled Write Data To NV RAM Request Must Execute bDataInit First *)

     nDevId : UINT; (* Id In System Manager *)

     nAccessLen : UDINT := 5; (* Access Len In One PLC Cycle *)

     nDataLen : UDINT; (* Backup Data Block Size (In Byte) *)

     pDataAddr : UDINT;

     nBlock0Offs : UDINT; (* Dual Memory Block n0 Address *)

     nBlock1Offs : UDINT; (* Dual Memory Block n1 Address *)

     tTimeOut : TIME := T#10S;

END_VAR

Note :

nAccessLen => Access NV-RAM Length In Once PLC Command

nDataLen => Backup Data Length，The Actual Back up Size = nDataLen – 1

And Never Use the Last BackupData Byte

VAR_OUTPUT

     bInitalReadFinish : BOOL;

     bBlockDataRestored : BOOL;

     nRestoreFromBank : INT;

     bBusy : BOOL;

     bError : BOOL;

     bBlockUpdated : BOOL;

     nWriteBankId : INT;

     AccessTime : TIME; (* actual backup time *)

END_VAR

Note :

AccessTime => NV-RAM Backup Time

Data Export / Import To Disk also Available In System Manager

Important !!!

Always reserve one byte of NOV-RAM space for data correctness check.

Never overlap the reserve byte!!!

2012/5/10 advan lee

Contact : Jidien Beckhoff Application Team

B.Service@jidien.com