Problem with SAVE command

[Raghav]

Hi all,

I use a motion program to run the PSET command and then I issue a SAVE command in the same motion program to save certain parameters before the RETURN line. The program execution is fine, but after its execution, certain PLC's are disabled. PLC 1,2,3,6 are disabled but PLC 4,7 are enabled. Before the SAVE command execution, PLC 2, 6 are enabled by the user but once we find the status of the PLC after the command, it's is not active. To check whether the save command creates the issue, we disabled the save command and the PLCs are fine. What causes this issue and how to overcome this while using SAVE command as well?

[steve.milici]

We would always recommend against using the "SAVE" command in any PMAC program. Having said that, when the "SAVE" command is issued all background processes are temporarily stopped such as PLCs and PMAC's WD timer resetting (PMAC accommodates this during the "SAVE" process). All RTI tasks and above will continue to execute normally. There is no way to overcome this process.

[Richard Naddaf]

Read about fast save (FSAVE) in the Turbo Software Reference Manual

[steve.milici]

What are the PMAC parameters you need saved at this point in your program?

[Raghav]

What are the PMAC parameters you need saved at this point in your program?

 

I just save around 6 P-variables after setting X Y Z values using PSET. Hope PSET doesn't need to be followed by SAVE command

[steve.milici]

In this case the "FSAVE" would be a better choice to use. The "PSET" command does not require a "SAVE" as it has only transient action within the coordinate system.

[Raghav]

In this case the "FSAVE" would be a better choice to use. The "PSET" command does not require a "SAVE" as it has only transient action within the coordinate system.

 

Hi Steve,

Thanks for the information. I tried using FSAVE and it works fine. I tried to retrieve back the data after PMAC power-on and I could get the value without FREAD. Is it fine to use without FREAD? Also do I need to FSAVECLEAR periodically since it was mentioned in the manual that after every 256th cycle, the data needs to be cleared. Also the we could use FSAVE for 25,000,000 times, will it be an issue if I use it since the user might more often use the code which will use FSAVE command.

[Gregs]

You will need to use FREAD after power cycling; otherwise, FSAVE values will be overwritten with the last SAVE values. Perhaps you did not need to use FREAD because the last FSAVE and SAVE values were the same.

 

You should not need to use FSAVECLEAR. The only issue would be if two FSAVEs are issued within 2 seconds of each other. And, issuing FSAVECLEAR before each 256th FSAVE would prevent the use of half of the memory space, thus reducing the expected life of the used half, by half.

 

Speaking of expected life, just how often do you expect to issue an FSAVE? You could issue an FSAVE 2,747 times a day for 25 years before you hit 25,000,000! Not enough?