Simatic S5-95U trouble to Run Mode

Dear All members,

I'm now working with Siemens PLC S5-95U. Seriously, this is my first time I'm working with siemens plc product.

I'm face problem to turn this cpu to run mode. There have operation mode switch in this plc. The switch already at Run Mode operation but indicator still show for STOP Operation. I'm tried to reset the plc, but the trouble still remain. What i need to do to solve this problem? Maybe the toggle switch got problem? Who know?

Thank a lot for members who reply this thread.

p/s : I'm cannot monitor ladder due to dont have software and communication cable to connect to cpu..

zai_jnr said:

p/s : I'm cannot monitor ladder due to dont have software and communication cable to connect to cpu..

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This also means that you can't go online to look at the ISTACK for diagnostic informatin

Was this PLC running ok before? Did something special happen when the PLC went to STOP (maintenance?).

You could start by checkking the supply voltage from all the IO cards.

If this plc has had the battery removed for sometime then remove the battery, switch from run to stop then back again a few times, then to stop, then fit the battery while still powered up, then switch to run, this generates DB1 this is used for configuration, however if the program is still in then you need to go online to see what is causing the error.
oops didn't read the full message it sounds like you have a plc with a program in it, then it's either lost it's program or there is a fault either in the cpu or possibly in the I/O, check all I/O backplane modules etc.

Jobbe said:

This also means that you can't go online to look at the ISTACK for diagnostic informatin

Was this PLC running ok before? Did something special happen when the PLC went to STOP (maintenance?).

You could start by checkking the supply voltage from all the IO cards.

Click to expand...

Dear Mr Jobbe,

Thanks for your reply. This is old printing machine the we have in our plant. After we install new machine in our plant, old machine, we power off for back up machine. If I'm not mistaken, this old machine we already power off within a few month.There have a few PLC unit that same spec and same brand in this machine. The only one cannot to go to run mode.

I've got study regarding ISTACK and DB1, due to I dont have the software to monitor the ladder, I can do nothing with software side. I'll try to check what you have recommend.

parky said:

If this plc has had the battery removed for sometime then remove the battery, switch from run to stop then back again a few times, then to stop, then fit the battery while still powered up, then switch to run, this generates DB1 this is used for configuration, however if the program is still in then you need to go online to see what is causing the error.
oops didn't read the full message it sounds like you have a plc with a program in it, then it's either lost it's program or there is a fault either in the cpu or possibly in the I/O, check all I/O backplane modules etc. .

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Thanks Mr Parky for your reply,

I think at the PLC Unit there have EPROM that attach to the unit. But I'm not sure what program inside. I think I want to do all reset cpu ( erase plc memory) procedure then try copy the program inside EPROM. But this is very risky troubleshoot because not sure in EPROM programming. Is it same with programming in plc unit.

You powered off the machine for a few months. Is the backup battery still OK? There should be a LED on the CPU somewhere to indicate this.

Erasing the CPU can be dangerous if you do not know what is on the EPROM. Do you still have the original program?

Jobbe said:

You powered off the machine for a few months. Is the backup battery still OK? There should be a LED on the CPU somewhere to indicate this.

Erasing the CPU can be dangerous if you do not know what is on the EPROM. Do you still have the original program?

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Already check the battery. Its good.
Original program we dont have keep due to this is old machine that we bought second hand.

zai_jnr said:

Original program we dont have keep due to this is old machine that we bought second hand.

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So you don't have the original program, you are not sure what's on the EPROM and you don't have the STEP5 software to go online.

My advice is to find someone who does have the STEP5 software and hire him for a day to fix your problem, check the EPROM and make a backup of it.

Jobbe said:

So you don't have the original program, you are not sure what's on the EPROM and you don't have the STEP5 software to go online.

My advice is to find someone who does have the STEP5 software and hire him for a day to fix your problem, check the EPROM and make a backup of it.

Click to expand...

After reconfirm back with machine supplier, they said EPROM that attach on CPU have the back up program. Already trial to make overal reset procedure and copy back program from EPROM to CPU. But still fail. I'm not sure either copy program procedure is not good or what. I'm not sure, when the complete program download have done.

zai_jnr said:

After reconfirm back with machine supplier, they said EPROM that attach on CPU have the back up program. Already trial to make overal reset procedure and copy back program from EPROM to CPU. But still fail. I'm not sure either copy program procedure is not good or what. I'm not sure, when the complete program download have done.

Click to expand...

Is it my CPU was damaged?
When I make overal reset then switch ON the battery toggle switch. I was tried to copy program from EPROM to CPU PLC. As regard manual, need to turn toggle switch to COPY a few second then release. That time stop indicator will blinking until remain turn ON. That mean program download complete.Then need to turn toggle switch to RUN mode and indicator RUN will ON.

What I have done,toggle switch to COPY a few second then release but indicator STOP will remain ON when switch release ( never blinking to show download program in progress..its blinking when toggle switch remain in COPY position). Is it CPU damage? If CPU not damage..what I need to do for next action?..Please help me my friend..

How exactly did you do the reset and program copy? This is the procedure from the manual:

Overall reset
Remove the battery (just in case)
Set the operating mode switch to "STOP".
Remove the battery.
Set the ON/OFF switch to "0".
Change the ON/OFF switch to "1".
Insert the battery.

Load the program from an (E)EPROM
Switch off the S5-95U
insert memory card
Press down and HOLD COPY key
Switch on S5-95U
Release COPY key

If the red LED is lit continuously you don't have a valid program on the memory card. If it is flashing ou need a PG for further diagnostic.
If the program is being loaded the LED should be flickering.

DO NOT press down the COPY key when the power is already on. This could erase the memory card if it is an EEPROM.

Issue settle. What I've done is remove the battery while PLC power up. Then turn operation switch from stop to run a few times. Then PLC go to Run Mode. I follow procedure reply by parky ( post#3).

Thanks a lot to all members who reply to my post.