Modbus driver
Observe these guidelines when working with Modbus controllers.
Protocols
The Modbus communication driver supports these protocols:
-
Modbus TCP. TCP Socket access mode.
-
Modbus RTU. Serial port access mode.
Data types
The Modbus communication driver supports these data types:
| Data type | Length |
|---|---|
|
Bool |
1 bit |
|
Byte |
1 byte |
|
SByte |
1 byte |
|
UInt16 |
2 bytes |
|
Int16 |
2 bytes |
|
UIn32 |
4 bytes |
|
Int32 |
4 bytes |
|
Uint64 |
8 bytes |
|
Int64 |
8 bytes |
|
Float |
4 bytes |
|
Double |
8 bytes |
|
String |
80 characters by default |
|
Array |
Data areas
The Modbus communication driver supports these data areas:
| Area | Modbus Function Code (Hex) | Addressing | Data Type | Access | Ranges |
|---|---|---|---|---|---|
|
Single Coils |
01 Read 05 Write (Single) |
Coil Status |
Boolean |
Read/Write |
0-65535 |
|
Coils |
01 Read 15 Write (multiple) |
Coil Status |
Boolean |
Read/Write |
0-65535 |
|
Discrete Inputs |
02 Read |
Input Status |
Boolean |
Read Only |
0-65535 |
|
Single Register |
03 Read 06 Write |
Holding Register |
Word |
Read/Write |
0-65535 |
|
Multiple Register |
03 Read 10 Write |
Holding Register |
Word |
Read/Write |
0-65535 |
|
Input Register |
04 Read |
Input Register |
Word |
Read Only |
0-65535 |
Tip: The addressing may differ from device to device. For more information, refer to the device documentation.