There are several settings in the ViX that are considered to be System Variables and not commands. The actual position, PA, is one of them.
To read a system variable the syntax is: nR(xx)
where n stands for the device address and xx stands for the system variable.
For example, to read the actual position on a ViX with the address of 1, the syntax is:
1R(PA)
To set a System Variable the syntax is nW(xx,yy)
where the n stands for the device address, the xx stands for the system variable and the yy stands for the value of the variable
For example, to set the actual position to zero on a ViX with the address of 1, the syntax is:
1W(PA,0)
Some System Variable are read-only and others can be either written to or read from..
Please refer to your user guide for a list of System Variables.