Feed Rates in imperial

math_indy

A work-around that I am thinking about trying might also solve your feed rate problem.  I too use DDCSV2.1 Imperial (inch) mode on a surface grinder whose Z-Axis has very fine motion.  The lowest acceleration/deceleration allowed is 9 mm/s^2 which isn't low enough (remember 9 mm/s^2 = 54 mm/min./s).  OK, so the work around that I am thinking about trying might also solve your issue.  Here is it:

I am thinking about leaving my DDCSV2.1 in metric (mm) mode (parameter #115) and, instead, scaling the pulse equivalent axis parameters (#34,#35,& #36) by a factor of 25.4.  In this way the displays will be calibrated in inches but I will have 25.4 times finer control of the acceleration parameters that are causing my issue.  After reading your post I realized that this work-around might also fix the G-Code feed rate issue as all G-Code motion AND feed-rate will be scaled up to inches by the 25.4 scale factor.  The only drawback of this work-around is the DDCSV2.1 display will still say "mm"--a large sticker indicating that readings are in inches will be my solution for that.