Register Map Profiles
Describe a device once as a profile of addresses, data types, scale factors and units, then reuse it across every identical meter.
Protocol Support
Modbus Integration
Poll Modbus RTU and Modbus TCP devices, decode registers with the right word order and scaling, and publish clean engineering values.
- Standard
- Modbus Application Protocol (Modbus Organization)
- Medium
- RS-485 or RS-232 (RTU), Ethernet port 502 (TCP)
- Topology
- Client and server (master and slave)
- Data Model
- Four tables: coils, discrete inputs, input registers, holding registers
What Modbus Is
Modbus is the simplest and most widespread industrial protocol. A client asks a server for a block of registers and gets numbers back. The numbers have no names or units, so the real work is the register map: which address is the voltage, how many registers make a 32-bit float, and which word comes first.
Native address
Unit 5 (RTU, 9600 8N1)
Holding register 40012
FLOAT32, word swap
scale 0.1
Normalized tag
site.plant-1.mdb-03.active-power
184.2kW
How IoTServa Connects Modbus
Byte and Word Order
Choose big or little endian and word swap per register block, so a 32-bit float reads correctly the first time.
RTU and TCP Together
Poll serial devices on RS-485 and Ethernet devices on port 502 in one project, with per-device timing.
Polite Polling
Group contiguous registers into single requests and set per-bus timing so a long daisy chain stays responsive.
Typical Jobs
- Sub-metering and power quality
- Variable frequency drive status and faults
- PLC and generator data into one history
- Retrofitting old equipment with no network
Plan for These
Register addresses are written two ways: with or without the 40001 offset. Confirm against the device manual.
RS-485 needs correct termination, biasing and a unique slave address per device.
A value with a wrong word order looks plausible but is wrong. Always check one reading against a known value.
Modbus Questions
Do I need to write the register map myself?
You can, or send the device manual and the engineering team will build the profile. Profiles are reused for every identical device.
Can IoTServa read both serial and Ethernet Modbus?
Yes. Modbus RTU over RS-485 and Modbus TCP are both supported and can sit in the same project.
Bring Your Modbus Devices. We Will Read Them.
Tell us the make and model of what is on site. We will scope a pilot against your real equipment.