Hello

I have a question, i use a s7-1500 cpu 1510sp and i check the manual.

1- The retentive memory area for datablock is 88kb.

2- The db set not retentive became initial value when start cpu from power off

3- The retentive memory of cpu don't change dimension with a different type of mmc.

All this is correct?

And now my question:

1- I can increase the retentive memory of this cpu or i need a different cpu?

2- have some mode for save data as retentive when power off without use a retentive data area?

3- i can save with a command on the program the actual value of db on the initial value?

Thank you in advance for your support

Best Regards

Hello,

I have a question, i use a s7-1500 cpu 1510sp and i check the manual.

1- The retentive memory area for datablock is 88kb. Right (Available retentive memory for bit memories, timers, counters, DBs, and technology data (axes))

2- The db set not retentive became initial value when start cpu from power off, yes

3- The retentive memory of cpu don't change dimension with a different type of mmc. yes, independent on MMC

All this is correct?

And now my question:

1- I can increase the retentive memory of this cpu or i need a different cpu?

An:  its fixed for each CPU, select higher range of S71500 PLC for more retentive memory

2- have some mode for save data as retentive when power off without use a retentive data area?

Ans: You need to define the retentive area.

3- i can save with a command on the program the actual value of db on the initial value?

you  take  snap shot of DB  for initialize the value.

If you are not defining the retentive area then after power on CPU will take initial value as startup.

If you feel this post is useful then don't forget to rate.

Hello

Thank you DJ_1 for your support.

Only The last answer i'm not sure i understand correctly.

Snapshot is a command of tia portal and i can make manually for the programming software. If i want make this command automatically with a routine inside a plc it's possible? 

My problem it's: i have data change continuously and this data need is retentive, but i have some data will change only by user from the display and i want preserve this data change when append. my idea is put this data in a initial value of the db form one automatic routine inside a plc. 

Thank you in advance for your support

Best regards

Hello,

Snap shot is online feature by using engineering software. With the help of snap shot , you can take snap of current values of DB and later when ever you want , you can restore again same values as initial values. I don't think so, snap shot will helpful in  your case. you need to define that memory as retentive.

I recommend looking into the manual "SIMATIC S7-1500, ET 200SP, ET 200pro Structure and Use of the CPU Memory": https://support.industry.siemens.com/cs/ww/en/view/59193101

... and into the FAQ about "Using Recipe Functions for persistent Data with SIMATIC S7-1200 and S7-1500": https://support.industry.siemens.com/cs/ww/en/view/109479727

Regarding retentive data you should consider working with optimized DBs, because there you are able to decide for each variable (rather than for a complete DB) whether it should be retentive or not. If you do that and they don't fit into your CPU you need to think about a different solution, e.g. a larger CPU.

Hi.

Have you considered to use the recipe feature on the HMI to carry some of the values that you need to store?

It would also be possible to make use of the MMC to store values there.

Would any of these ideas help you?

Greetings.
w

Hello

I think i use the DBtoCSV function for make this work. i don't want put this data on the display.

1-I want test if the db you can convert to csv need is retentive. I the manual is writed "retentive db to csv".

2- the other test is when i put the db value to csv and after csv to db the value became initial value or not. if not is a problem, i need make this movement every time i start the cpu.

i need test.

thanks all for your support. when i finish my test i post the result.

if someone have maked this please give me information.

best regard