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 58 minutes
- Pulse meters: dry pulse vs active pulse Compare dry contacts, open-collector and active voltage pulse outputs. Check wiring, isolation, pulse timing and scaling before connecting a meter. 13 min
- Pulse meter commissioning and reconciliation Commission a pulse meter connection step by step: output circuit, pulse weight, maximum rate, a known-count test, recovery and reconciliation with the meter register. 5 min
- Heat meter data monitoring and reconciliation Read the right heat-meter register, store it with its meter, unit and time, and reconcile the totals with the meter display and the network balance. 11 min
- Wired M-Bus commissioning for heat meters Commission a wired M-Bus segment: unit loads, bus voltage and capacitance, primary addresses, telegram records, failure tests and reconciliation with 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 process signals: loop headroom, scaling at known points, NE 43 fault currents, live-zero voltage, RTD transmitters, sampling and an acceptance record. 10 min
Modbus and RS-485
7 guides · about 52 minutes
- Modbus RS-485 commissioning Commission Modbus RTU over RS-485 step by step: device contract, wiring, termination and bias, addressing, decoding, polling time, data quality and an acceptance record. 6 min
- Modbus TCP vs Modbus RTU The differences between Modbus TCP and Modbus RTU: transport, framing, addressing, port 502, timing, gateways and security, and how to choose for an existing site. 6 min
- RS-485 vs Modbus vs RS-232 RS-485 is an electrical interface and Modbus is a protocol. What each one defines, how RS-232 and RS-422 compare with RS-485, and what to ask for before you connect a device. 9 min
- RS-485 wiring, termination and bias How to wire an RS-485 bus for Modbus RTU: daisy-chain topology, stub length, where termination goes, how bias works, A/B polarity, the common conductor and cable length. 8 min
- Modbus register maps: addresses, data types and scaling How to read a Modbus register map: holding and input registers, 40001 and zero-based addresses, 32-bit and 64-bit values, word order, scaling, status bits and not-available values. 7 min
- Modbus troubleshooting: timeouts, exceptions and wrong values How to find the cause of a Modbus timeout, an exception such as 02 illegal data address, a value that decodes but is wrong, or a value that freezes, with raw RTU frames and 9600 baud timing. 11 min
- Protocol gateway vs transparent bridge What a device called a gateway can do: tunnel serial bytes, convert Modbus RTU to Modbus TCP, or translate data between protocols such as BACnet and Modbus. How to test each one. 5 min
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 each byte order.
- 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 the Modbus register words in every byte order.
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.