Modbus Motion Interface
Write_Double(<AxisPage>_+_NegativeLimit_d,<Value>);
Read_Double(<AxisPage>_+_NegativeLimit_d);
Description
Set Negative Limit establishes a negative-direction boundary for movement. If the commanded position on the axis falls beyond this boundary, a Position Limit Escape Code will occur and the move will not commence. Jogging is not subject to software limits since jogging is used for ongoing motion. Note that the parameter is a signed value. A common mistake when a machine has the origin in the middle is to set the Positive Limit and Negative Limit to the same value. However, the limits are a software boundary measured with an offset from the origin; assigning them the same value places them in the same location which makes all other commanded locations out of range. Negative limits have negative numeric parameters unless the desired range of motion is exclusively positive from the origin. Software limits are always active but can be effectively disabled by being set with large values.
When designing homing routines it is usually necessary to widen the software limits until the coordinate system is established to afford freedom to search for the home sensor. Once the origin of the coordinate system is found the limits can be re-established.
Escapes
The Negative Limit register does not generate any escapes
Examples
This operation sets the soft limit in the negative direction to be -10:
Write_Double(Axis1_+_NegativeLimit, -10);
Reading the negative limit can be done with this operation:
Limit:=Read_Double(Axis1_+_NegativeLimit);
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