Transmission Specifications; Calculating The Current Position In Machine Coordinates - YASKAWA SGD7S Product Manual

6.8 Absolute Encoders

6.8.5 Transmission Specifications

6.8.5

Transmission Specifications

The position data transmission specifications for the PAO (Encoder Divided Pulse Output) signal are
given in the following table.
The PAO signal sends only the multiturn data.
Refer to the following section for the timing of sending the position data from the absolute encoder.
6.8.4
Synchronization Method
Transmission Speed
Start Bits
Stop Bits
Parity
Character Code
Data Format
Data Output Period
Data Format of PAO Signal
As shown below, the message format consists of eight characters: "P," the sign, the 5-digit multiturn
data, and "CR" (which indicates the end of the message).
P
+ or −
0 to 9
0 to 9
0 to 9
0 to 9
0 to 9
CR
6.8.6

Calculating the Current Position in Machine Coordinates

When you reset the absolute encoder, the reset position becomes the reference position.
The host controller reads the coordinate Ps from the origin of the encoder coordinate system. The host
controller must record the value of coordinate Ps.
This section describes the reference position in the machine coordinate system.
The method to calculate the coordinate value of the present position from the origin of the machine
coordinate system is given below.
Machine coordinate
Value of
multiturn data
The current position P
P = P
M
P = M
E
P = M
S
6-36
Reading the Position Data from the Absolute Encoder
Item
Start-stop synchronization (ASYNC)
9,600 bps
1 bit
1 bit
Even
ASCII, 7 bits
Refer to Data Format of PAO Signal.
Each time the SENS_ON command is input after the
control power supply is turned ON
Multiturn
data (5 digits)
-1
-1
in the machine coordinate system is calculated as follows:
M
- P
E S
×
R + P
O
×
R + P '
S S
on page 6-35
PAO signal
Origin (reference position)
0 +1
+1
±0
M × R
P
E
P P
S M
Current position
+2 +3
+2
P
O