*SetCoupler() - symmetric coupler pair
Sets the ratio for a coupler pair.
Syntax
*SetCoupler(coupler_name, LEFT|RIGHT, ratio)
    Arguments
- coupler_name
 - The variable name of an existing coupler pair.
 - LEFT|RIGHT
 - If LEFT is specified, the properties are assigned to the left coupler, and the right coupler properties are made symmetric to the left coupler.
 - ratio
 - The value of the coupler ratio.
 
Example
*RevJointPair( j_bearing1, "Bearing 1", b_shaft1, 
 b_shaft1_hsg, 
 
 p_shaft1_hsg, 
 V_Global_Y )
*CylJointPair( j_bearing2, "Bearing 2", b_shaft2, 
 b_shaft2_hsg, 
 p_shaft2_hsg, 
 v_hsg2_align )
*CouplerPair( cpl, "Gear", j_bearing1, 
 j_bearing2, 
 ROT, 
 ROT )
*SetCoupler(cpl, LEFT, 10.2)