Siemens logo

[redlinej]

Hi,
I would like to share an experience with you guys.
The other day at work,one of the operator told me that the air compressor is operating in emergency mode, where all protect is by pass.So I when to trouble shoot the problem,find out that the Siemens logo was not in run nor stop mode although the power supply to it was okay.So the problem was the 10 year old plc,but we did not have any to replace it with, so we were at a dead end and not wanting the compressor to operate without protection we had to resolve the matter soon.
So I start looking around and find another logo form a next machine that was working but password protected so I could not program it using the key on the logo and also I did not have the programming software nor the cable.I dismantle the damage logo and remove the power board and replace it with the password protected logo power board and power it up,the plc power up and work find with its memory intact.
I am sharing this experience not because I replace a power board on a plc and it worked but because sometimes we over think stuff,like did they use addressing between the power board and the control board,Some times you just have to give it a your best shot.and for your who are wondering, I did check all protection before handing the compressor back to the operators.

 

[itsmoked]

You got lucky! Well done and thanks for the story.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[jraef]

Kudos to you for not giving up and being creative in finding a solution.

Now I want to know... If your compressor is so important to the function of your facility, and it cannot operate safely without that smart relay (it's not really a PLC), why is it that your company does not invest the $100 to keep a spare on hand at all times? Certainly if you count your time and effort in investigating this (and lucky for them it was you and not someone less capable), experimenting, recommissioning it and the cost of lost production in the time it took you, that component cost was likely exceeded 100 fold or more. I only point it out as a cautionary tale for any plant managers that happen to read this (he says knowing full well it's only a dream). I just finished a large project with 104 VFDs in a packaging line for a perishable product, and submitted my suggested spare parts list, basically 2 control boards, a list of power modules of each size, fuses and a keypad. It was rejected by management as too expensive! Absolutely foolish...


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington