siemens plc115u cpu941b

[tonycobby]

emergency.i have a cpu941b cpu thats been running acouple of years until yesterday.none of the outputs are working,the inputs appear to be correct,but i dont get any outputs.the plc goes into run but i dont have any outputs.

 

[moggie]

Is there a program in the CPU?
Was the CPU in stop mode? If so how did you start the CPU
Is the program in RAM or E(e)Prom
Is the battery ok (if on RAM)
Have you the s5 software and interface lead to connect to the PLC?

Steve

 

[tonycobby]

cpu siemens

theorically there is a program.we do have tha eeprom in the cpu.
we dont have soft or cable,cant give you more informacion,sorry.

 

[tonycobby]

siemens cpu

hello moggie i understand that i havent helped much.in a short while
i should have a laptop with soft and cable.could i have a problem
with the racks.i have two im306 connecting the racks,i left the link cable off to try and simulate an error but the cpu went to run.which
means that the cpu does not monitor the second rack.ive lifted off all of the output cards and replaced one by one but i still dont have any outputs.do i have a problem inside the program thats holding off the outputs.

 

[tonycobby]

siemens

i now have a pg710 hooked up to the unit.i have a copy of the program on disc.ive taken the eeprom out and wiped out the ram.mounted one input card inslot zero and one output card in slot four.wrote a one line program ld e0.0 out a16.0.in status i can see the input changing
state but the output doesnt come on.has anybody had this problem before?

 

[RRobbins]

I am assuming you have power to the output card. There is a fuse on some of the output cards. If this is one of the original cards, check for a fuse. Can you force the output? Overall reset the processor, go to force variables and write a value to output word 16 and see if the lights come on. If all output cards act the same, replace the backplate, test the outputs and then the processor.

 

[tonycobby]

siemens

been working all night on this one.now i have more info ,see if anyone can give me a hand.
ive got here,cpu 941,one rack with four 32bit input cards and one im306,an expansion rack with 3 32 input cards and 5 32 bit output cards and a im306.
i disabled the second rack and left just one input card in slot 0
and one output card in slot 1.wiped the memory and did a one line program.ld e0.0 out a4.0.this works okay.leaving the input card where
it was i moved the output card to the right and changed to out a8.0.
okay.
did this trial with all the vacent slots leaving the input card where it was,and enabling the slot number via the im306.this rack works correctly.
i have a spare new im306.changed the im306 on the expansion rack for the new one and hooked up the link cable.inserted in slot 3 of the
expansion and changed my one line program to out a28.0.i configured the im 306 the same as the original.the output on my pg says it is on but i dont have anything on the output card.i have a spare link cable,ive changed it,but i still have the same problem.
stripped out the two backplanes.checked continuity on the pcb,even though they are fine tracks they were all okay(i dont know how they are reacting when installed with all the cards plugged in,but because i dont have a spare theres little i can do there.)

 

[tonycobby]

siemens

its amazing what a shower and lots of coffee,plus the brilliant idea
of rrobbins,can do to cheer up a sunday morning.it appears that i have all of my five output cards kaput,broken,no good,all i have to do now is find four new output cards(i have one spare)here in malaga
on a sunday morning.well at least ive made a bit of progress.
thanks rrobbins.