Hey guys,
I have a welding application that we are trying to upgrade. It is currently using 1990 integrated hardware and we want to upgrade to a more readily available PLC type control. It is a TIG application and currently you press a button to position the torch. The torch is mounted to a linear slide driven by a stepper motor. The torch drives towards the workpiece, the tungsten touches the work piece and reverses for "x" amount of time providing an initial starting arc gap. Using a meter there is 5VDC from the work piece to the tungsten. This is called the touchsense voltage. Then there is a High voltage relay that isolates the controls from the High Frequency starting arc. I have a Compactlogix TTL input module that I'm going to try but I don't have much experience with this particular module nor TTL in general. I know that if you can pull the voltage down low enough in makes the input turn on. So my question is if I have DC COM connected to the torch through the high voltage relay and my 5V signal from the TTL input connected to the workpiece as soon as the tungsten makes contact it "in my thinking" should pull the voltage down and turn on the input. Then I can reverse the stepper to gain my arc gap. Any ideas are very much appreciated. I can just see letting about 87 2/3% of the smoke out of my controller!
I have a welding application that we are trying to upgrade. It is currently using 1990 integrated hardware and we want to upgrade to a more readily available PLC type control. It is a TIG application and currently you press a button to position the torch. The torch is mounted to a linear slide driven by a stepper motor. The torch drives towards the workpiece, the tungsten touches the work piece and reverses for "x" amount of time providing an initial starting arc gap. Using a meter there is 5VDC from the work piece to the tungsten. This is called the touchsense voltage. Then there is a High voltage relay that isolates the controls from the High Frequency starting arc. I have a Compactlogix TTL input module that I'm going to try but I don't have much experience with this particular module nor TTL in general. I know that if you can pull the voltage down low enough in makes the input turn on. So my question is if I have DC COM connected to the torch through the high voltage relay and my 5V signal from the TTL input connected to the workpiece as soon as the tungsten makes contact it "in my thinking" should pull the voltage down and turn on the input. Then I can reverse the stepper to gain my arc gap. Any ideas are very much appreciated. I can just see letting about 87 2/3% of the smoke out of my controller!
