I have a problem setting high STEP_RATIO values.

Answer:

There is a ratio limit on the step ratio of 100:1

STEP_RATIO(-12600, 126) is OK but any higher ratio will give the error.

Using a high ratio like the above is actually not a good idea. You are telling the controller to produce a step change in drive position of 100 counts for just 1 count of the DPOS. You will be better using CONNECT with the ratio you want. However even with CONNECT, if you have a high ratio, the axis will jump around because for every 1 count of the master, it will jump the high number of counts in one msec. The motion could be very rough.

Better to have a virtual master and set the UNITS of that to be the same as the actual real axis.

BASE(vm)

UNITS = 12600 ' 12600 is 1 mm

BASE(n)

STEP_RATIO(1, 1)

UNITS = 12640

CONNECT(1, vm)

MOVE(1000) AXIS(vm) ' move the virtual master 1 metre.