Sometimes Length Matters

I have been meaning to upgrade the electronics on IceBot One to the latest MakerBot Gen 4 for several months now, I wanted to get in on some Volumetric 5D action and set myself up for the addition of the Gen4 Interface.

I had previously decided that it would be a good idea to move the electronics to a more accessible location to make it easier to access the SD card slot. For those who don't know, my machine is a little different than most. IceBot One is a reclaimed CNC, in its former life it was an automated inspection machine for the semiconductor industry. Compared to a Makerbot or RepRap this thing is huge, 4'x4'x6' and tipping the scales at 1,500lbs . Yeah that's pretty big, so it shouldn't be a surprise that when routing cables from one end of the machine to the other a few feet of cable may be needed.

The new Gen4 Motherboard location required about 4 feet of cabling to reach the Gecko Drives that run servo system, as well as the steper drivers located on the z-axis.  I did'nt think the long cables would be an issue since there are plenty of long cables in the system already and I don't have issues with those, but after a few hours of playing around printing calibration cubes it became obvious that something was wrong. Everything I printed came out slanted by a few degrees.

At the same time as the hardware upgrade I also performed an update to ReplicatorG 29 r2 and Skeinforge 49 so it wasn't out of the realm of possibility that the software upgrade was causing the problem.  I performed a continuity check on the cables but that turned out just fine.  I checked to make sure none of the cables ran past anything emitting high frequencies, but there was nothing near the cables.  I started to suspect that the long cables were causing a delay in the step and direction pulses.  If I had access and knowledge I could have probably used an osiliscope to verify that this was the problem but I don't roll like that.  I relocated the Gen4 motherboard to the same location as the old Gen3 motherboard and shortened the cables to about 6".  It should come as no surprise that this solved my issues, now i can get on with calibration and start printing again.