Command: Change Master (79)

Supported Axes:	Position Control Axes
Supported Control Modes:	Position PID, Position I-PD
Firmware Limitations:	RMC75/150: 3.56.0 or newer

See the Commands Overview topic for basic command information and how to issue commands from PLCs, HMIs, etc.

Command Parameters

Parameter Description

Range

Master Register

Note: See Specifying aRegister Address below.

_Time or any other valid register of type REAL.

Description

This command immediately changes the master register of a curve that is currently in progress on the axis. A curve must currently be in progress on the axis when this command is sent, or a Command Error will occur.

If the velocity of the old master and the new master are different, the axis may experience a jerk when the master changes. Therefore, this command is intended to be used only when the speed of the old master and new master are approximately equal. An example application is the execution of a curve across the transition from one master conveyor belt to another master conveyor belt.

When the master is changed, the master endpoints are recalculated relative from the position of the new master at the time of the change.

Specifying a Register Address

When issuing this command from anywhere other than RMCTools, the addresses in the Master Register command parameter must be entered as an integer value.

RMC addresses are represented in IEC format as:

%MDfile.element, where file = file number, and element = element number.

Use the following equation to convert a register address to integer format, N:

N = file * 4096 + element

Example:

_Time:

The register address for the _Time tag in the RMC75 is %MD20.10. Therefore, the value is 20*4096 + 10 = 81930.

The register address for the _Time tag in the RMC150 is %MD44.10. Therefore, the value is 44*4096 + 10 = 180234.

The register address for the _Time tag in the RMC200 is %MD18.10. Therefore, the value is 18*4096 + 10 = 73738.