Now, that's a really practical device a lot of shops can actually use. I'd love to see the source code but I can understand it not being there. You could actually market the device. What transducer did you use? I like the fact that you made it look good by putting the lettering on the front panel. It shows you didn't just make it for yourself. Good work.
I agree. Seems like a very practical idea. I'm curious, though. In hydraulic ram press applications in the past, how was the force calculated? Mr. Nauman mentions counting the number of pumps on a handle. Was the calulation really that crude?
The force is simply the hydraulic pressure times the surface area of the cross section of the ram. The pressure transducer was calibrated in the laboratory and the instrumentation amp gain is set to allow maximum range for the A/D converter in the PIC. The PIC does the simple E.U. conversion to provide the LCD display with actual pounds force exerted by the ram.
The schematic was drawn in Sunstones free printed circuit board design program, PCB123. PCB123 does not allow any format other than theirs. The only way to transmit the schematic to design news was via a screen capture and a JPG conversion. If you want an electronic version, I will be happy to email anyone a copy. But PCB123 does not allow any format other than theirs, so you will have to download PCB123 to be able to open it. If you are interested, email me and I will send you a schematic and the code for the PIC. If you plan to build one, I would be happy to program the PIC for you if you don't have the means to do so.
This is cool. I built my own 50-ton shop press using old fork-lift rails and would love to have this gadget.
However - Seems like there's some confusion here over relatively simple concepts. Such as equating the number of pumps on the handle to force? Doesn't the number of pumps equate to the volume of oil going into the ram which would equate to distance of ram travel? I would have simply gone to Excel; created a nice laminated graph correlating pressure to force and taped it to the press.
Adding a device to precisely measure the travel distance of the ram could be useful.
In the "old days" a pressure gauge was used, located similarly to the pressure transmitter in this application. On some rams, the gauges were calibrated in lbs (or Tons), rather than psig, or sometimes both. I don't recall ever seeing one with a settable pointer, but that would be an obvious useful feature.
I needed a set of jacks made with pressure gauges like this once. We used them to check the compression force of springs on packaging equipment in several plants. We planned on calibrating them so we knew the force/PSI reading, and then using a table. But a little work by our supplier let us select a hydraulic jack that had a cylinder area close enough to 1" that we could just take the gauge reading in PSI and read it as lbs force. We confirmed it with a force gauge in the shop, and it was bang on.
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