Output → PCO 1CN-24 Encoder Output
V- CMP (1CN-8) (for speed/torque control only) COIN (1CN-8) (for position control only)
7) Absolute Data Exchange Sequence
The Servopack sends absolute data to the host controller when receiving output from a 12-bit absolute encoder. This data exchange sequence is described below.
Use the following detailed information when designing a host controller.
a) Outline of Absolute Signal
The 12-bit absolute encoder outputs PAO, PBO, PCO and PSO as shown on the right.
Signal
Name Status Contents
PAO
Initial state Serial data
Initial incremental pulse PAO
Normal state Incremental pulse
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Servopack
Frequency dividing circuit
b) Contents of Absolute Data
Serial Data: Indicates how many turns the motor shaft has made from the reference position (position specified at setup).
Initial Incremental Pulse: Outputs pulses at the same pulse rate as when the motor shaft rotates from the home position to the current posi-tion at the maximum speed of 4,900 r/min.
Coordinate data
Reference position
(setup) Current position
Value M
Absolute data PMcan be determined using the following formula.
PE Current value read by encoder PE= M ¢ R+PO M Serial data (rotation count data) PE= M ¢ R+PO
PM= PE− PS PO Number of initial incremental pulses (Normally, this is a negative value)
PS Number of initial incremental pulses read at setup PM Current value required for the customer system R Number of pulses per encoder revolution
(pulse count after dividing, value of Cn-0A)
c) Absolute Data Transmitting Sequence
For speed/torque control (SGDA-jjjS).
(3) Set the SEN signal at high level.
(4) After 100 ms, set the system to serial data reception-waiting-state.
Clear the incremental pulse up/down counter to zero.
(5) Receive eight bytes of serial data.
(6) The system enters a normal incremental
op-eration state approximately 50 ms after the last serial data is received.
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SGDA- S
Speed/Torque
Undefined
Rotation count
serial data Initial incremental pulse
Incremental pulse (Phase A) (Phase A)
(Phase B) (Phase B) Incremental pulse
Rotation count serial data Undefined
Undefined
Initial incremental pulse
1 to3 ms
10 to
15 ms Approx.
23 ms
For position control (SGDA-jjjP).
A 12-bit absolute encoder outputs PAO, PBO, PCO and PSO as shown below.
Servopack Serial data
Frequency dividing circuit
Absolute data is read from phase S (PSO) as serial data. It is first output from PAO as serial data when the Servopack is turned ON. Next, it is output as initial incremental pulses PAO and PBO (two-phase pulse with 90° phase difference).
Then, output operation becomes the same as normal incremental encoder operation (two-phase pulse with 90° phase difference).
Rotation count serial data is output from PSO. Absolute data must be processed in the following sequence.
Servopack power supply
Encoder power supply
Serial data Initial incremental pulse
Incremental pulse Undefined
Rotation count serial data
*Encoder power is automatically turned ON inside the Servopack.
Undefined
(Phase A) (Phase A)
(Phase B) (Phase B)
Undefined
Approx.
23 ms 120 to 300 ms
1 to 3 ms
Use PAO, PBO and PCO as necessary. If PAO and PBO are used, absolute data is output to PAO and PBO when power is turned ON as shown in the figure above. How-ever, since encoder power ON timing is not adjusted within the processing circuit pre-pared by the customer, absolute data cannot be read via PAO or PBO.
3
SGDA- P
Positions
d) Detailed Specifications of Each Signal
• Specifications of PAO Serial Data:
The number of revolutions is output in five dig-its.
Data transmission
method Start-stop synchronization (ASYNC)
Baud rate 9600
Start bit 1 bit
Stop bit 1 bit
Parity Even number
Character code ASCII 7-bit code
Data format 8 characters. As shown on the right.
• Specifications of PSO Serial Data:
The number of revolutions and the abso-lute position within one revolution are al-ways output in five and four digits, respec-tively. The transmission cycle is approximately 40 ms.
Data transmission method
Start-stop synchronization (ASYNC)
Baud rate 9600
Start bit 1 bit
Stop bit 1 bit
Parity Even number
Character code ASCII 7-bit code
Data format 13 characters. As shown on the right.
• Incremental Pulse and Home Position Pulse:
Initial incremental pulses which pro-vide absolute data are first dipro-vided by the frequency divider inside the Servo-pack and then output in the same way as normal incremental pulses.
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“P” or “A” “+” or “-”
Data
Start bit Even parity
• Data is P+00000 (CR) or P−00000 (CR) when the number of revolu-tions is zero.
• The maximum number of revolu-tions is 99999. If this value is ex-ceeded, it returns to 0000.
”0” to “9”” “CR”
“P” or “A”
“+” or “-”
Number of revolutions: “0” to “9”
Absolute position within one revolution:
“0” to “9”
Data
Start bit Even parity
• Absolute position data within one revolu-tion is a value before frequency dividing.
(4,096 pulses per revolution)
• Absolute position data increases during forward rotation (standard setting).
(Not valid in reverse rotation mode)
“CR”
“
,
”Phase A Phase B Phase C
Forward
rotation Reverse
rotation
• Note that phase C is not divided so its pulse width is narrower than phase A.
Phase A Phase B Phase C
• Use the following user constant to set the pulse dividing ratio.
Cn-0A
PGRAT Dividing Ratio Setting
Unit: P/R Setting Range:
16 to Number of Encoder Pulses
Factory Setting:
2048
For Speed/Torque Control and Position Control
Set the number of output pulses for PG output signals (PAO,
*
PAO, PBO and*
PBO).Pulses from motor encoder (PG) are divided by the preset number of pulses before being output.
The number of output pulses per revolution is set in this user constant. Set this value accord-ing to the reference unit of the machine or con-troller to be used.
The setting range varies according to the en-coder used.
Motor Type Number of Encoder Pulses Per
Revolution Setting Range
SGM-jjj31j Incremental encoder: 2048 pulses
per revolution 16 to 2048
SGM-jjjW1j Absolute encoder: 1024 pulses per
revolution 16 to 1024
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Servomotor encoder
Servopack
Output terminals:
PAO (1CN-20)
*PAO (1CN-21) PBO (1CN-22)
*PBO (1CN-23)
Setting example:
Preset value: 16
1 revolution Phase A Phase A
Phase B
Phase B Output
Fre-quency divider