Lossing memory when powering off Omron CJ1G-H

Matthias von Zorn · May 19, 2006

Hey all. Im back with some more omron questions. Im having the issue that when I power off the PLC, I loose all the data in my PLCs memory. Its not loosing its program, but all its setpoints, etc. So, everytime we power up, I loose all my PID settings, All my alarm limits, etc. I tried setting dip switches 2 and and or 7 on the PLC, but they didnt seem to work. Its in the W memory area. There is a battery, and it seems to be hooked up as well. Obviously there must be someway to keep variables alive between power ups. Thanks in advance.

Matt

Leadfoot · May 19, 2006

I like to do a move set up function on the first pass. I move the value I want into the memory area where it is needed. You can do just one first pass instruction and have as many move blocks as you want/need.

rsdoran · May 19, 2006

I am not familiar with OMRON but sounds to me like the memory areas were not set to be retentive. On some brands you have to designate if the memory is retentive or non-retentive.

Usually if a battery goes dead the whole program is lost but I would verify the battery is good anyway.

Maybe Jay or Bob can offer more if they drop in.

rsdoran · May 19, 2006

Since I am not that familiar with Omron I took the time to look at some manuals, in this manual there are some notations;
http://oeiwcsnts1.omron.com/marcom/pdfcatal.nsf/0/719FFA45E523A20286256FD60070FB25/$file/M11W340E1111of3.pdf

Look on page 27 but not sure it is relevant:

The user program and parameter area data in the CS1-H, CS1D, CJ1-H,and CJ1M CPU Units are backed up in the built-in flash memory. The BKUP indicator will light on the front of the CPU Unit when the backup operation is in progress. Do not turn OFF the power supply to the CPU Unit when the BKUP indicator is lit. The data will not be backed up if power is turned OFF.

ALSO:
The contents of the DM, EM, and HR Areas in the CPU Unit are backed up by a Battery. If the Battery voltage drops, this data may be lost. Provide countermeasures in the program using the Battery Error Flag (A40204) to re-initialize data or take other actions if the Battery voltage drops.

Matthias von Zorn · May 19, 2006

Yea, I saw that, but it doesnt seem to help me at all. I also cant have a move from a first pass, because this data is set by a HMI, so its a variable, so that first pass block would be empty then as well. I have seen some things around, and I have a feeling the W area is not backed up by battery? I hope this isnt the case, and that im missing some setting somewhere, but I cannot seem to locate it. Ive played with the dip switches by the battery and they dont seem to change its behaviour.

gtsuport · May 19, 2006

Sorry, but you are correct. The W area is not retentive.

H and D area ARE retentive.

Possible options would be to change HMI (no fun). Or set up a XFER instruction to move the W works to H or D memory at some point when you know you have valid data. Then XFER the data back to the W words with the First Scan Pulse. Not really pretty, but it would work.

Hope this will help.

scottmurphy · May 19, 2006

Another option would be to use the D memory area instead of W, this is what I do, and use the W area at the bit level.

BobB · May 19, 2006

There are 3 memory retentive areas that are battery backed up in Omron PLCs. These are the DM, EM and HR areas.

I normally use the DM area for what you are trying to achieve but you could use the HR area also.

The DM and EM areas are basically word data only. The HR area can be used for word data but is more typically used for bits.

The DM and EM areas can only be directly addressed as words. However, if you wish to strip bits out of the DM area then move the DM to CIO or W area.

The HR area can be directly addressed an words or bits.

Hope this helps.

Matthias von Zorn · May 22, 2006

Im going to replace all the W with HR, and change the HMI as well. Dont know about the PLC, but changing the HMI is as easy as a dump to excel, replace, import. Could be worse.

gtsuport · May 22, 2006

Just a thought. If you setup the HR bits in the right way, you may just be able to use a XFER instruction and transfer the HR words to the existing W words and not have to modify the plc code.

Hope this will help.

Lossing memory when powering off Omron CJ1G-H

Matthias von Zorn

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Leadfoot

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rsdoran

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rsdoran

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Matthias von Zorn

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gtsuport

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scottmurphy

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BobB

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Matthias von Zorn

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gtsuport

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