Meter interfaces
Pulse outputs, wired M-Bus, Modbus RTU, P1 ports and analogue signals from the meters a site already has.
Most sites already have meters with a pulse output, M-Bus, Modbus or a P1 port. Reading them is often cheaper than fitting new sensors.
Start with the guide for the interface on your meter's label, then use its commissioning checks.
Meter interfaces
6 guides · about 62 minutes
- Pulse meters: dry pulse vs active pulse A pulse output meter sends one pulse per fixed quantity of energy, gas or water. Compare dry contact, open-collector, S0 and active outputs, timing and scaling. 14 min
- Pulse meter commissioning and reconciliation Commission pulse metering: output circuit, pulse weight, maximum rate, known-count tests, recovery and reconciliation with the meter register. 5 min
- Heat metering: how heat meters work and how to monitor their data A heat meter calculates thermal energy from water flow and the flow and return temperatures. How heat metering works, classes, M-Bus or pulse reading. 14 min
- Wired M-Bus commissioning for heat meters Commission wired M-Bus: unit loads, bus voltage, capacitance, primary addresses, telegram records, failure tests and checks against the meter display. 11 min
- P1 port guide: DSMR smart meter data How Dutch DSMR and Belgian eMUCS P1 smart-meter ports work, including the RJ12 pinout, telegrams, OBIS codes, commissioning checks and the DSMR6/X1 transition. 8 min
- Commissioning 4-20 mA and 0-10 V monitoring Commission analogue signals: loop headroom, scaling, NE 43 fault currents, live-zero voltage, RTD transmitters, sampling and acceptance checks. 10 min
Modbus and RS-485
9 guides · about 87 minutes
- What is Modbus? How the Modbus protocol works Modbus is a request and response protocol: a client reads and writes numbered registers in a server. Data model, function codes, RTU and TCP frames. 11 min
- Modbus RS-485 commissioning Commission Modbus RTU over RS-485: device parameters, wiring, termination, bias, addressing, decoding, polling, data quality and acceptance checks. 6 min
- Modbus TCP vs Modbus RTU Modbus RTU vs Modbus TCP in one table: RS-485 or Ethernet, CRC or MBAP header, bus address or IP and unit ID, port 502, timing, gateways and security. 11 min
- RS-485 vs Modbus vs RS-232 Is Modbus the same as RS485? No: RS-485 is the physical layer and Modbus the protocol that runs on it. A comparison table, Modbus RTU, and RS-232 vs RS-485. 11 min
- RS-485 wiring, termination and bias RS-485 wiring for Modbus RTU: cable, RJ45 and D-sub pinout, daisy-chain topology, stubs, termination, bias, A/B polarity, common conductor and length. 11 min
- Modbus register maps: addresses, data types and scaling What a Modbus register map contains and how to read one: the four register types, an example row, 40001 addresses, 32-bit values, word order and scaling. 9 min
- Modbus troubleshooting: timeouts, exceptions and wrong values Fix Modbus RTU and TCP timeouts, exception 02, wrong decoded values and frozen readings. Includes timeout arithmetic: 125 registers take 292 ms at 9600 baud. 11 min
- Protocol gateway vs transparent bridge Distinguish serial tunnels, Modbus RTU-to-TCP conversion and translation between protocols such as BACnet and Modbus, with tests for each. 5 min
- Reading refrigeration controllers over Modbus: Danfoss, Carel and Dixell Serial settings, signed temperature registers and scaling for Danfoss EKC 202, Carel MPXPRO and ir33, and Dixell XR refrigeration controllers. 12 min
More in Meter interfaces
- Modbus and BACnet gateways: types and how to choose oneThe five devices sold as a Modbus, BACnet or IoT gateway, what each one does, how to size the polling load and a checklist for choosing one.
- Three-phase energy meters with Modbus: how to choose and read oneChoose a three-phase energy meter with Modbus for the supply, current, accuracy and interface, then read its registers correctly and commission it.
Calculators
All calculators- 4-20 mA scaling Scale a 4-20 mA signal to engineering units or back, including square-root flow.
- Modbus address converter Work out which register a device map means: zero-based offset, one-based number or 40001-style reference.
- Modbus function and exception codes Look up any public Modbus function code, data object or exception code, with its request limits.
- Pulse meter scaling Convert pulse counts to energy and check pulse rate, pulse width and counter capacity.
- 0-10 V signal scaling Scale an analogue voltage signal to engineering units, including spans that do not start at zero.
- Pt100 and Pt1000 Convert between resistance and temperature for Pt100 and Pt1000 sensors, with tolerance class limits.
- Modbus CRC and LRC Calculate the CRC-16 for a Modbus RTU frame and see the byte order on the wire.
- Modbus register decoder Decode integer and floating-point values from Modbus registers in four displayed byte orderings.
- Modbus RTU timing Calculate character and frame timing on a Modbus RTU link, and how long a polling cycle takes.
- Wired M-Bus segment Check unit loads, far-end voltage and bus capacitance for a wired M-Bus segment.
- M-Bus address planner Check an M-Bus primary address schedule for duplicates and reserved addresses before commissioning.
- 4-20 mA loop voltage Check a 4-20 mA loop has enough supply voltage at its design current.
- RTD lead resistance error Estimate the temperature error that lead resistance adds to a two-wire or three-wire RTD.
- RS-485 termination and bias Check where termination and bias resistors belong on an RS-485 Modbus network.
- IEEE 754 float converter Convert decimal numbers to IEEE 754 hex and back, with Modbus register words in four displayed ordering patterns.
EpiSensor products
Devices for this topic
Modbus meters
All Modbus meters
LoRaWAN pulse counters
All LoRaWAN pulse counters
Connecting meters that are already installed?
Tell System Builder which meters you have and what interface each one has. It finds the interface product for each meter.