Serial Communications - Invertek Optidrive P2 series Installation & Operating Instructions Manual

9. Serial communications

9.1. RJ45 Connector Pin Assignment
Optidrive P2 has an RJ45 connector on the front of the control panel. This connector allows the user to set up a drive network via a wired
connection. The connector contains multiple interfaces for different communication protocols:-

Invertek's Optibus Protocol - Used for PC and peripheral connection only

Modbus RTU

CANBus
The Optibus connection is always available, and can be used simultaneously with other interfaces, however only one other interface may be
used, e.g. If Modbus RTU is in use, CAN is disabled. If a Fieldbus Option Module (E.g. Profibus) is inserted into the drive, both Modbus and CAN
are disabled.
The electrical signal arrangement of the RJ45 connector is shown as follows:
9.2. Modbus RTU Communications
9.2.1. Modbus Telegram Structure
The Optidrive P2 supports Master / Slave Modbus RTU communications, using the 03 Read Holding Registers and 06 Write Single Holding
Register commands. Many Master devices treat the first Register address as Register 0; therefore it may be necessary to convert the Register
Numbers detail in section 0 by subtracting 1 to obtain the correct Register address. The telegram structure is as follows:-
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Optidrive ODP-2 User Guide Revisions 2.10
Command 03 – Read Holding Registers
Master Telegram Length
Slave Address 1 Byte
Function Code (03) 1 Byte
st
1 Register Address 2 Bytes
No. Of Registers 2 Bytes
CRC Checksum 2 Bytes
Command 06 – Write Single Holding Register
Master Telegram Length
Slave Address 1 Byte
Function Code (06) 1 Byte
Register Address 2 Bytes
Value 2 Bytes
CRC Checksum 2 Bytes
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CAN-
CAN+
0 Volt
Optibus / Remote Keypad / PC Connection -
Optibus / Remote Keypad / PC Connection +
+24 Volt Remote Keypad Power Supply
RS 485- Modbus RTU
RS 485+ Modbus RTU
Slave Response
Slave Address
Function Code (03)
Byte Count
st
1 Register Value
nd
2 Register Value
Etc...
CRC Checksum
Slave Response
Slave Address
Function Code (06)
Register Address
Register Value
CRC Checksum
Length
1 Byte
1 Byte
1 Byte
2 Bytes
2 Bytes
2 Bytes
Length
1 Byte
1 Byte
2 Bytes
2 Bytes
2 Bytes