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The application is force vs. distance monitoring of small hydraulic assembly presses. We are currently using the Sciemetric Sigmeters successfully, but we want to see what else is on the market. We have looked at offerings from Burster, Kistler, HBM, and Promess (I might have that last name a bit wrong). There seems to be two basic approaches. One is signature envelope, in which you set a tolerance band around a "good" signature. The other is to have various types of tolerance boxes which you can set at arbitrary points in the signature. The Sigmeter is a programmable device, so it lets you do arbitrary tests. It is very flexible, but it is also more complicated. Some of the other devices are simpler to use, but you only get what features were designed into them. Does anyone know of an instrument they would particularly recommend? Is there one you would avoid? We are looking for: - True force vs. distance (not force vs. time). - The sampling rate should be better than 1 kHz. - The linear transducer only needs a working stroke of 25 mm or so. This could be a linear pot or encoder. - The force transducer should be a load cell. We use the strain gauge style, but I understand that some people use piezo in this application. We would prefer to stick with our current load cells. - The instrument should be rugged, user friendly, etc. - The case should mount through a hole in a panel (with the user interface visible). - It should be compact. 150mm wide by 75mm high by 300mm long would be good. This is not a hard spec, but this is roughly the expected size range. - Calibration and parameter settings should be through a keypad on the front. - Signature display on the front of the instrument (LCD graphics) would be nice, but we don't have it now. - A digital I/O interface to a PLC must be possible. Please, no suggestions involving custom software and "an old PC". I have to live with these things after they are installed. ********************** Michael Griffin London, Ont. Canada [email protected] **********************
