Encoder_ratio / Step_ratio

Encoder_ratio / Step_ratio

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.

    • Related Articles

    • CONNECT command

      Question: I use the CONNECT command and when I change the ratio the encoder slave doesn't move in the axis. I see the pulses of the master encoder move. This is the code: BASE(0) ' slave (following) axis SERVO = ON UNITS = 4000 DEFPOS(0) BASE(2) ' ...

    • Analog incremental linear encoder input to Trio

      We are looking to retrofit a Trio controller to a 3 axis CNC machine which has heidenhain analog incremental linear encoders fitted (1Vpp - 40um linear period) but unsure which if any controller has this function available. Can you advise please - ...

    • P375 card with 3 stepper - MPOS and DPOS in error

      Even with open loop stepper, the P375 has an encoder counter that counts the pulses and sends them back to the controller so that we can do registration. The feedback is in pulse counts but DPOS is in counts x 256. Therefore it is necessary to set ...

    • AN-333 BiSS Encoder support

      A BiSS implementation has been added to some Trio controllers to support reading of encoder position from devices fitted with a BiSS interface.  This document explains how to integrate BiSS encoder to Trio

    • MC508 P849 EnDat encoder input

      We are to propose a solution for 6axis step&dir and 2 ENDAT encoders reading. I would like to be sure the P849 is able to manage the two requests together. Yes, EnDAT will work on any of the first 8 axes. It does not work if there is another axis ...