96
•
Appendix A - MODBUS RTU Protocol
byte 4: Starting Address Low
($00)
byte 5: No. of Coils High
($00)
byte 6: No. of Coils Low
($08)
byte 7: CRC_Low
($XX)
byte 8: CRC_High
($XX)
The ASTAT-XT response when coils 7..0 are OFF OFF OFF ON OFF ON OFF OFF:
byte 1: Serial Link No.
($0A)
byte 2: Function
($01)
byte
3:
Byte
Count
($01)
byte 4: Data (coils 7..0)
($14)
byte 5: CRC_Low
($XX)
byte
6:
CRC_High
($XX)
Example 7 - Force Single Coil:
To stop the motor controlled by ASTAT-XT # 1, the host computer writes "1" to the "STOP COIL" (coil 1 addressed as 0)
.
Note:
For the Force Single Coil Function, Force Data of $0000 forces "0" = OFF. Force data of $FF00 forces "1" = ON.
The "Query" frame is sent by the host:
byte 1: Serial Link No.
($01)
byte 2: Function
($05)
byte 3: Coil Address High
($00)
byte 4: Coils address Low
($00)
byte 5: Force Data High
($FF)
(force ON)
byte 6: Force Data Low
($00)
byte 7: CRC_Low
($XX)
byte 8: CRC_High
($XX)
The Normal (if no exception) response:
byte 1: Serial Link No.
($01)
byte 2: Function
($05)
byte 3: Coil Address High
($00)
byte 4: Coils address Low
($01)
byte 5: Force Data High
($FF)
byte 6: Force Data Low
($00)
byte 7: CRC_Low
($XX)
byte 8: CRC_High
($XX)
Notes
:
1.
Format is identical for the 3 "discrete" commands: Stop, S.Stop, Start & Reset. For these commands, writing
"OFF" to coil is meaningless. For example, when the ASTAT-XT is in the Stop condition, Coil #1 (Addressed as
0) = 1 (ON). Forcing the Stop Coil #1 to OFF does nothing. However, forcing the Start Coil (#3) to ON will turn
ON the Start Coil, but will also turn Off the Stop Coil.
2.
For Energy Save, Dual Adjust, Slow Speed & Slow Speed Reverse Coils, writing "ON" will turn the option ON,
while writing "OFF" will turn it OFF .
Example 8 - Force Multiple coils:
The motor that is controlled by ASTAT-XT # 32 is stopped, Energy Save, Dual Adjust, Slow Speed and Reverse are set
to OFF.
To start the motor using the Dual Adjust parameters and enable Energy Saving feature (after end of starting), the
host computer should write "1" to the Start , Energy Save and Dual Adjust Coils no. 3-5, addressed as 2-4.
The "Query" frame sent by the host:
byte 1: Serial Link No.
($20)
byte 2: Function
($0F)
