math for distance-confused/braindead

[kcor 1]

question have a encoder that gives me 120 pulses per 1 inch of travel. trying to figure out how to program so that a opertor could enter in a menu on nt20s display to move 1 inch or any value from 0-3 inches in increments such as 1.3 inches or 2.7 inches, etc. if 120 pulses = 1 inch, then if i divide 1 by 120, which equals .0083, then for every pulse, then the encoder has moved .0083 inches. So if a operator wanted to enter a value of 1.4 to move 1.4 inches, then any advice on how to accomplish this would be appreciated. I have worked on it for a couple of hours now, and just can not quite figure out the best approach. using a cqm1h cpu51, and trying to modify a program that is written with syswin. Any advise.

[gtsuport 61]

Probably an easier way, but just a quick check came up with this. Multiply the operator entered value 1.4 (14 in plc register) by 10000, using a double multiply. Then double divide result by 83 to get the number of pulses required. I think this will work, maybe not the cleanest way to do it. Hope this helps.

[Nibroc 4]

... Hi, GT's way should work fine and is probably the easiest way to program, note also that the CQM1H series supports floating point numbers (as expansion instructions). So you could convert your values to floating point, perform the calcs then convert them back. Nibroc Edited 15 Nov 2005 by Nibroc

[kcor 1]

thanks for feedback will be going to a branch plant tomorrow and will try the suggestion.