Origin Settings; When Using An Absolute Encoder - YASKAWA E-7S SERVOPACK SGD7S Product Manual

12.3 Origin Settings

12.3.1 When Using an Absolute Encoder

12.3

Origin Settings

It is necessary to define a reference position to operate a device or machine. This is done with
origin settings.
The origin settings depend on whether an absolute encoder or an incremental encoder is used.

12.3.1 When Using an Absolute Encoder

If you use an absolute encoder, it is not necessary to set the origin every time the power supply
to the equipment is turned ON.
However, when you set up the equipment, you must set PnB25 to the offset between the origin
of the absolute encoder and the position of the origin of the reference coordinate system
(called the machine coordinate system).
When you start a system that uses an absolute encoder, you must initialize the absolute
encoder and adjust the position of the machine origin. Then you must set the offset that defines
the origin of the reference coordinates.
PnB25
*
If you set PnB54 to 1 (Enable Expansion Mode), the range will be -1,073,741,823 to +1,073,741,823. Refer to the
following section for details.
12.4 Speed/Position Expansion Function Setting on page 12-8
Perform one of the following operations to set the offset.
• Execute the ZSET serial command.
• Execute utility function FnB09.
• Calculate the value and set it in PnB25.
The relationship between the origin of the absolute encoder and the machine origin coordinate
system is shown in the following figure. Use the following formula to find a new absolute
encoder offset.
PnB25 = Current PnB25 + N − P
N: Current position of machine in new reference coordinate system
If this position is to be defined as the origin, then normally N is 0.
P: Current position of machine in current reference coordinate system
You can use the PON or MON1 serial command (described later) to monitor this value.
Reference (machine)
coordinate
Encoder coordinate
12-6
• When using an incremental encoder: Origin
• When using an absolute encoder: Absolute Encoder Offset
Setting Range Setting Unit
-99,999,999 to
1 reference unit
99,999,999*
Absolute encoder origin
Default Setting
0
Current origin in reference
coordinate system
(Origin of reference coordinate
system = Machine origin)
New origin of reference
coordinate system
= New machine coordinate
Current position of machine in
current reference coordinate system (P)
Current PnB25 = −X
- (P − N)
New PnB25
X X
Coordinate of current machine origin
in encoder coordinate system
When Enabled Classification
After restart Setup
Current position of machine
Current position of machine in
new reference coordinate system (N)