S7-200 retentive data was lost??

arpus4KM

Lifetime Supporting Member
Join Date
Sep 2021
Location
Mid
Posts
614
Need some insight into why this happened. After finally getting a VM to connect to a CPU 216 2 siemens processor, uploaded the program. made a change to an output being used due to one gone bad, and downloaded the program back in and all of a sudden nothing worked.


Troubleshot it down to the fact that all of the saved data for program settings was cleared, ie, Temp settings, delays, cycle timers, etc. so all retentive data that was supposed to be kept in place, it all went to 0.


I double checked what could have happened, set some data again, and uploaded, then downloaded and it didn't clear anything out this time. but then power cycling the machine cleared it back to 0, except that I thought these were supposed to be in the retentive ranges set in the program.




Is there some special setting in S7 Micro/win that i'm missing? do i need to do more than the download function with the blue arrow at the top? should i be using the store program to memory funtion or is that basically the same as having a second eeprom memory module installed for a second backup?
 
What are the settings in your project? When you download if the start value is set to 0, it will change that setting to 0 when you download.
 
When downloading to the PLC you have to deselect the Data Block to stop it overwriting memory.

Retentive ranges are backed up by a Super Capacitor that lasts about 4 days, for longer than that you need a battery module, which are now stupid expensive. Super Capacitors can and do fail. If you have a Battery Module you can dismantle it and replace the actual battery bit. The battery is a standard cheap coin cell. The only tricky bit is not breaking the plastic battery module as you try to remove the PCB that houses the battery.
 
What are the settings in your project? When you download if the start value is set to 0, it will change that setting to 0 when you download.

yes, I realized that all too soon. unfortunately now when we change a setting via the hmi, and power cycle, the data doesn't stay retained anymore. So this is a new problem to figure out. I'm just very unfamiliar with siemens functionality

When downloading to the PLC you have to deselect the Data Block to stop it overwriting memory.

Retentive ranges are backed up by a Super Capacitor that lasts about 4 days, for longer than that you need a battery module, which are now stupid expensive. Super Capacitors can and do fail. If you have a Battery Module you can dismantle it and replace the actual battery bit. The battery is a standard cheap coin cell. The only tricky bit is not breaking the plastic battery module as you try to remove the PCB that houses the battery.


I found some information that specified selecting data block when uploading to grab that data as well.... I'll be going back to figure out their address blocks so we can get it rolling again by reverse engineering the pathways for their hmi machine function selections.


If I have a range of data in the retentive memory ranges system block, what would keep it from retaining that data over a power cycle? it appears that it's mostly default except for one range (clicking default all only changes one range, canceled out to make sure it didn't take effect though). I've seen some stuff in the manual about using the SMB31.7 and SMB32 bits to tell it what range to retain, is this necessary? theres no logic like that in this program to continually writing variables to retained memory.
 
Last edited:
It appears the retentive data section is working properly.

what happened is that I did indeed not get the save rom to ram and variable information saved in blocks before the download. So what I had was a blank set of variable that was thrown into the mix. unfortunately.... Now I have the issue of trying to figure out this unlabeled program to get this machine running again.



The alternative is selling them on an upgrade to an already obsolete by 10 years PLC to something new, and now siemens so we don't have to worry about all these extra problems. I don't know about anyone else, but Siemens feels weird to work with after doing so much with AB.
 
Not only are you responsible for any work required to restore the machine to operational condition but you are also responsible for loss resulting from down time.

I suggest you roll up your sleeves, get a wiring diagram and spend as much time as needed with the machine operator to get as good as an understanding as you can of the machine.


Good luck.
 
Last edited:

Similar Topics

Hello I've got a customer with a two year old machine, and he's telling me that on power up, the retentive data is being lost. This has just...
Replies
2
Views
3,420
Having trouble with a Siemens S7 226 counter being retentive. I have specified in the System block C ranges offset 0, 6 elements. However, at...
Replies
0
Views
265
Hi Guys, I am embarrassed to ask - but I just can't seem to find the right dialog box! I am using TIA V11, with a S7 1214. I wish to make some...
Replies
2
Views
2,363
Is there a way to create retentive tags in the KTP1000 basic panel using S7 Basic, so if the power to the touch screen goes out, the tag retains...
Replies
6
Views
5,987
hI CAN ANYONE TELL ME IF THERE ARE ANY RETENTIVE BITS/REGISTERS IN THE AB ML1200 OR IS THERE ANY WAY OF MAKING CERTAIN BITS RETENTIVE????? ALEX
Replies
9
Views
3,434
Back
Top Bottom