This parameter is used to stop following and move a slave axis to an absolute position while not stopping the slave.

The Absolute Bias is the difference between the Bias - returned by the GetFollowerBias function - and the additive commanded position to a slave axis. The Absolute Bias can be used in conjunction with an absolute move command (ABS_MOVE) to position the follower axis to a position that can be calculated.

The commanded position to a slave axis is the sum of the position command from following the master and the Bias:

Command_pos = SlaveMethod (master_pos + master_offset) + Bias;

The Bias is also composed of two parts:

Bias = additive_pos_command + abs_bias;

The Absolute Bias can be used to position the follower axis to some known absolute position if the value from the FollowerMethod function is known and is constant. One situation where the Absolute Bias can be used is during gearing to stop following the master axis but to keep moving the follower axis at a continuous speed. Set the FOLL_BIAS_REMAINS Follower Mode bit to 1, and use the SetFollowerConfig function to configure the mode. Deactivate following, and immediately issue a continuous immediate move command in the desired direction with the desired speed. The Slave Ratio decelerates to 0 at the deceleration rate while the immediate movement accelerates to the desired velocity with the acceleration rate. Both of these ramps will occur simultaneously with each other leaving the axis moving at the desired speed when both ramps are finished (the follower axis RAMPING bit is cleared). In Ratio mode with a FOLL_BIAS_REMAINS and following deactivated, the SlaveMethod function part of the position command calculation is 0, giving:

pos_command = additive_pos_command + abs_bias;

The follower axis can now be moved to some absolute target by issuing an absolute move command, compensated by the Absolute Bias, or:

foll_axis.moveImmed (ABS_MOVE, target - abs_bias, speed);

Once this move's profile is completed, issue a halt or disable drive command to the follower, then normal move commands can be issued, unaffected by a Bias value.

The value returned is the Absolute Bias. If modulos are activated, the Absolute Bias is returned with modulo.

The function associated with this parameter is:

This function uses the WRITE_CMD instruction.