Modbus
Connect to Modbus devices
The Modbus feature of Cogent DataHub™ provides real-time data exchange between DataHub software and any Modbus TCP/Ethernet or RTU compliant slave device or PLC. The feature is available in three DataHub products, the DataHub Modbus OPC Server, DataHub Modbus Tunneller, and the DataHub Modbus Logger.
When combined with other DataHub features, each of these products provides the ability to fully utilize data from multiple Modbus devices, for example:
- Create a Modbus OPC Server
- Database connectivity to read and write Modbus data
- Implement slave-to-slave Modbus bridging
- Write Modbus data to Excel
- Create Email and SMS notifications based on Modbus data
Features of the DataHub Modbus Driver
The following Modbus features are supported:
- Unlimited connections to slave devices
- Automatic connection re-try with configurable delay
- Automatic message size optimization
- User-configurable options on a per-slave basis
- Host name / IP address and port for TCP
- Automatic IPV6 connection with fallback to IPV4 for TCP
- Serial port, baud, data bits, parity, stop bits, and RTS for RTU
- Polling rates from 10 ms
- Optional use of Modbus functions 5, 6, 15, 16 and 22
- Maximum message length from 20 to 260 bytes
- Zero- or one-based addressing
- Zero- or one-based bit addressing within registers
- MSB or LSB bit order within registers
- Flexible data point configuration:
- 16, 32 or 64-bit signed and unsigned integer input and output
- 32- and 64-bit floating point input and output in any byte order
- ASCII, UTF-8 and UTF-16 strings
- Range specification to configure many consecutive points at once
- Bit-field addressing within registers, including multi-bit fields up to 64 bits in length
- Bit range specification to configure many consecutive bits within a register at once
- Read-only mode for addresses in output data blocks
- Automatic next-in-sequence point configuration
- Arrays of digital and analog types
- Deadband for analog types
- Linear transformations with clamping
- Type conversion
- Addresses up to 65535
These products support Modbus:
| Product | Code | Features | ||
|---|---|---|---|---|
| DataHub Modbus UA Server | DHMBUA | * OPC UA, Modbus | ||
| DataHub Modbus DA Server | DHMB | * OPC DA, Modbus | ||
| DataHub Modbus Tunneller | DHMTUN | * Modbus, Tunnel/Mirror | ||
| DataHub Modbus Logger | DHMBLOG | * Modbus, Database | ||
| Modbus TCP or RTU support ** | ADDMB | Modbus |
* Includes Aggregation, Scripting, QuickTrend, and Security
** Available as an add-on feature
