MultiTool Creator code template automatically includes NVMemory (PRG) which handles non-volatile memory operations using SSeriesHardware library's NVMem (PRG).

All memory areas use the ParameterHandler library for handling the images between RAM and NVRAM. Parameter handler also checks the image integrity.

It is NOT recommended to save parameters in every program cycle. Especially OD parameter saving can be time consuming (depends on amount of parameters).

CANopen OD parameter saving can also be done from the CAN bus with SDO protocol but it is not covered by this example.

Refer to the following for adjusting and saving safety control unit OD parameters from a 6000 series unit:

• How to adjust safety parameters from display

• Parameters library

• ParametersSave (FB)

It is recommended to add new variables to the end of the structure.

Variable data types should not be changed in existing systems, to maintain integrity of the image.

Application default values are used when:

• NVRAM is empty (new unit)

• Both primary and backup memory area is corrupted.

Definitions:

TYPE FastParameters :

STRUCT

FastParameter1: BYTE;

FastParameter2: WORD;

FastParameter3: DWORD;

END_STRUCT

END_TYPE

Definitions:

VAR

local_var:BYTE;

trigger:BOOL;

trigger_old:BOOL;

END_VAR

Code:

G_Common.FastParameters.FastParameter1 := local_var;

IF trigger AND NOT trigger_old THEN

G_Common.SaveFastParameters := TRUE;

END_IF

trigger_old:=trigger;

Safe application code shall access safety parameters using the safe GVL (e.g. G_CAN1_SPAR).

Safe application shall check that the safety parameter CRC validation is OK using the variable G_SystemFlags_Safe.S_SafeOperationEnable

Copying parameter values to safety parameters is done only once at initialization, so changes in safety parameter's non-safety OD variables do not automatically affect the safety parameters.

Safety parameters are restricted to exist only in one CAN bus at a time.

When a CANopen OD parameter is defined as a safety parameter, the safety adjustment sequence is required when adjusting through CAN bus. Safety parameter adjustment is only disabled from the SDO server's side until authentication is enabled. This does not affect the application code.

All non-safety and safety parameters are in the same parameter image so OD saving is not different for safety and non-safety parameters.

If an application code needs to change a safety parameter OD index value from the CODESYS application, then it also needs to handle safety parameter CRC updating (see the example in How  to calibrate a joystick). Otherwise, CRC check will fail after boot-up.

CANopenODSave is a non-safety library so parameter saving is always used through non-safety context (called from non-safety Main PRG).

Definitions:

odSaveResult: EPEC_ODSAVE.SaveODErrors;

Code:

(*save parameters to nvram*)

G_CANopen_CAN1.SaveAll.Callback(o_Error => odSaveResult);