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Digitax ST User Guide
Issue: 5
Method 7 to 14: Homing on home switch and index pulse
These methods use a home switch, which is active over only a portion of
the travel; in effect the switch has a 'momentary' action as the axis's
position sweeps past the switch. Using the methods 7 to 10, the initial
direction of movement shall be to the right, and using methods 11 to 14
the initial direction of movement shall be to the left except if the home
switch is active at the start of the motion. In this case the initial direction
of motion shall be dependent on the edge being sought. The home
position shall be at the index pulse on either side of the rising or falling
edges of the home switch, as shown in Figure 9-15 and Figure 9-16. If
the initial direction of movement leads away from the home switch, the
drive shall reverse on encountering the relevant limit switch.
Figure 9-15 Homing on home switch and index pulse - positive
initial motion
Figure 9-16 Homing on home switch and index pulse - negative
initial motion
Method 15 and 16: Reserved
These methods are reserved.
Method 17 to 30: Homing without index pulse
These methods are similar to methods 1 to 14 except that the home
position is not dependent on the index pulse but only dependent on the
relevant home or limit switch transitions. For example methods 19 and
20 are similar to methods 3 and 4 as shown in Figure 9-17.
Figure 9-17 Homing on positive home switch
Method 31 and 32: Reserved
These methods are reserved.
Method 33 and 34: Homing on index pulse
Using these methods, the direction of homing is negative or positive
respectively. The home position shall be at the index pulse found in the
selected direction as shown in Figure 9-18.
Figure 9-18 Homing on index pulse
Method 35: Homing on index pulse
In this method, the current position shall be taken to be the home
position. This method does not require the drive device to be in
operational enabled state.
Use of controlword and statusword
The homing mode uses some bits of the controlword and the statusword
for mode-specific purposes. Table 9-95 defines the values for bits 4 and
8 of the controlword.
Table 9-95 Definition of bits 4 and 8 of the controlword
Table 9-96 Definition of bits 10 and 12 of the statusword
Bit
Value
Definition
4
0
Do not start homing procedure.
1
Start or continue homing procedure.
8
0
Enable bit 4.
1
Stop axis according to halt option code (0x605D).
Bit 12
Bit 10
Definition
0
0
Homing procedure is in progress.
0
1
Homing procedure is interrupted or not started.
1
0
Homing is attained, but target is not reached.
1
1
Homing procedure was completed successfully.
0
0
Homing error occurred, velocity is not 0.
0
1
Homing error occurred, velocity is 0.
1
X
Reserved.
Summary of Contents for Digitax ST
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