I have to change an old PLC on a very old pallet stacker which has approximately 70i/p and 70 o/p.
I am using SIEMENS PLC and as I am more experienced in S7-200 I prefer to do it with these instead of S7-300.
The problem is that the digital i/p of S7-200 accept DC volts and all the inputs on the machine are 24VAC.I have tested it in my workshop and the PLC operates ok with 24VAC on its inputs.Actually the i/p of SIEMENS are opto and they have two diodes which in this case rectify the AC without any problem.
I wonder if I can rely on this or if its a great risk of me visiting this factory all the time for problems caused by the PLC.
Does anybody have experience with such a case?
I am using SIEMENS PLC and as I am more experienced in S7-200 I prefer to do it with these instead of S7-300.
The problem is that the digital i/p of S7-200 accept DC volts and all the inputs on the machine are 24VAC.I have tested it in my workshop and the PLC operates ok with 24VAC on its inputs.Actually the i/p of SIEMENS are opto and they have two diodes which in this case rectify the AC without any problem.
I wonder if I can rely on this or if its a great risk of me visiting this factory all the time for problems caused by the PLC.
Does anybody have experience with such a case?