Microproto Control System Versions
The original Microproto controller required a three pin phase control for each motor from the parallel port on the PC. This therefore needed two parallel ports to provide signals for the fourth axis. This was modified in 2003 by the addition of the step and direction board, which converted the more modern step and direction signals created by Mach3 and other control software to the three wire signals needed by the stepper motor drive cards used in the controller. In 2006, Kurt produced a variant of the step and direction board which monitors encoders fitted to the stepper motors and produces a simple closed loop system.
Earlier phase controllers can be converted to step and direction versions can be converted to step and direction by the addition of a step and direction board. Step and Direction board Installation or they can be converted to a full closed loop system by the addition of a closed loop control board and encoders on each of the stepper motors. See the upgrade price list for the options to achieve this. MicroMillUpgrade
In addition to the Microproto step and direction upgrade, Homann Designs provide an alternative TurboTaig conversion board. This provides additional facilities direct on the PCB, such as LED monitoring of the control signals, and relay drives for the outputs. Something that the more basic Microproto Step and direction board does not provide. We have upgraded a number of systems using this board, but it is currently out of stock here and in Australia where it is manufactured.
Once converted to step and direction, the legacy software can be replaced by Mach3, and powered by a Mach-in-a-box computer. Mach3 needs at least Windows 2000 and a reasonable speed computer, so the earlier DOS/W98 based machines are probably not going to be powerful enough. As a stepping stone, Taig MPS2000 MaxNC mode on Mach3 details how three axies can be driven from Mach3 without the expense of the upgrade which is a useful first step to upgrading.
An alternative to Mach3 which does work well on older computers is the Linux based EMC2. This requires a little more care when setting up the software, but for a dedicated computer to run a CNC machine, it does offer a low cost approach which has received a lot of input in the last couple of years.
A final comment is the possibility of updating a 2003 open loop controller to closed loop. Since the drive electronics have not changed since Kurt originally designed the controller, there is no problem replacing the step and direction board with a closed loop board. The only problem comes with an intermediate batch of controllers that only has the one 25 way 'D' slot. Obviously once the need for a second connector for the fourth channel was removed, that slot was dropped from the case, but the encoder inputs then reinstated the requirement. A number of controllers do not have the second slot, and so conversion of these to closed loop requires a little bodge to bring the second ribbon cable out of the case. Replacing the end panel is not practical giving the number of through the panel components attached to it. We do also have a similar problem with the additional 8pin DIN connector, which the step and direction board adds, but it is somewhat easier to drill the extra holes for this if required.