Positioning with Digital Inputs | Home Position Return |
| |
4.3Home Position Return
At the factory the MR-J3-T servo amplifiers are configured with the incremental system activated by default (i.e. the absolute position detection system is switched off). This means that the current position is not stored when the amplifier's power supply is switched off, making it necessary to perform a return to home position every time the unit is powered up. You can configure the home position return mode with Parameter PC02:
Parameter PC02
Home position return modes
0: Proximity dog mode | 6: Count mode, front end reference |
1: Count mode | 7: Dog cradle mode |
2: Data setting mode | 8: Dog mode, last Z-phase reference |
3: Stopper mode | 9: Dog mode, front end reference |
4: Ignore home position | A: Dogless Z-phase reference |
5: Dog mode, rear end reference | |
The most commonly used modes are:
1.Dogless Z-phase reference mode (A)
2.Proximity dog mode (0)
These two modes are described in detail below. Dogless Z-phase reference mode is suitable for simple applications. Dog mode is frequently used for standard applications.
4.3.1Dogless Z-phase reference mode
In this mode the Z-phase of the rotary encoder (zero position of the encoder) is used as the machine's physical home position. However, it is quite rare to be able to configure a machine so that its physical home position exactly matches the Z-phase of the encoder. It is thus almost always necessary to enter an offset (shift) with parameter PC06.
After activation of the forward start command ST1 (or reverse ST2) the home position return is initiated by parameter PC04 (“home position return speed”). When the Z-phase signal from the encoder is registered the servo motor brakes to a halt. After this a precise return to home is performed at creep speed with parameter PC05.
The physical home position can be shifted in relation to the zero position of the encoder (Z-phase) with the home position offset (shift) defined with parameter PC06. Parameter PC07 can be used to define a home position value other than zero.
When the home position return has been completed successfully the servo amplifier activates the ZP signal.