Diehl Metering SHARKY 775 Modbus

Heat and cooling energy meter

SHARKY 775 is an ultrasonic heat and cooling energy meter with optional communication modules. With Diehl's powered Modbus RTU module installed, its measurements are available over EIA-485. The module manual gives exact read registers and an example energy request, so an installer can start with a read-only check before adding power, flow and temperature.

Diehl SHARKY 775 ultrasonic heat meter; the installed communication module is not visible
  • Modbus RTU

Heat and cooling energy meter

Compatibility

Read through the installed Modbus RTU module

Diehl publishes the SHARKY 775 module's EIA-485 settings, register table and a complete FC04 energy example. Edge can use a commissioned serial Modbus interface for read-only monitoring; this is a documented starting point, not a physical test of this meter.

This path requires the optional Diehl Modbus RTU module in a SHARKY 775. It does not describe the meter's separate M-Bus, wireless M-Bus, RS485-with-M-Bus-protocol or pulse modules. The read example follows Diehl's December 2023 module guide; compare it with the installed module and front display before expanding the point list.

Connect it with

When a SHARKY 775 has the optional powered Modbus RTU module and an approved isolated serial interface is available

  • Modbus
  • Edge
  • Platforms
Heat and cooling energy meter
Interface
Gateway
Edge
Output
SHARKY 775 ModbusSHARKY 775 Modbus RTU module, terminals 90/91
Isolated serial interfaceApproved RS-485-to-host adapter
ZGW-20 GatewayHosts Edge locally
EpiSensor EdgeEdge Modbus RTU client
Customer platformMQTT · API · files
Modbus RTU · RS-485
Isolated serial
Runs locally
Optional onward data
Supply the module at its separate 60/61 terminals, then connect its 90 (+) and 91 (-) data terminals to the EIA-485 bus. Use the installed module address and serial settings. Keep one Modbus master on the bus. The customer-platform output is optional; Edge remains the local system of record.

Models

Download
ModelsInterfaceRoute into Edge
SHARKY 775 plus Modbus RTU communication modulePowered optional EIA-485 Modbus RTU module; factory serial defaults 9600 bit/s, 8N1Read the module's measurement registers through an approved serial Modbus interface.
SHARKY 775 with M-Bus or RS485 M-Bus moduleDifferent communication modules and protocolUse an M-Bus master and the selected module's documentation; this Modbus table does not apply.
SCYLAR INT 8 plus the same Modbus RTU moduleAlso named in Diehl's module guideConfirm that meter's own configuration before reusing this read procedure.

Specifications

SHARKY 775 is an ultrasonic compact energy meter for heating and cooling. Diehl offers optional plug-in communication modules, so the physical meter model alone does not determine its external protocol.1

Measurement
Heating and cooling energy, with power, volume, flow and temperatures12
External read interface
Optional Modbus RTU module on EIA-485; other communication modules are separate12
Module supply
12–24 V AC/DC at terminals 60/61, separate from terminals 90/91 for EIA-4852
Serial defaults
9600 bit/s, 8N1; automatic slave ID enabled by default12
Measurement read
FC04 input or FC03 holding register reads; energy starts at zero-based offset 02
Energy representation
Signed Int32 with separate UInt16 factor and unit, or a convenience IEEE-754 float2

Interface

Documented measurements and integration boundaries for SHARKY 775 Modbus.

  • Thermal energy: signed 32-bit integer at input 30001 or holding 40001, wire offset 0, multiplied by the separate unit factor at offset 2; unit name starts at offset 3 and unit code is at offset 7.
  • Volume and power begin at offsets 10 and 20; flow begins at offset 30. Each has an integer value, unit factor, unit name and convenient float representation in the documented register group.
  • Flow and return temperatures are provided in their own groups, with unit information. Error code and meter identity can be read separately.
  • Keep thermal energy and volume counters distinct from instantaneous power and flow. Preserve the reported unit: the module can be configured for MJ, GJ, kWh or other published units.

Assessment

SHARKY 775 with Diehl Modbus RTU module, using the December 2023 public register guide. This is a documented read starting point; no physical EpiSensor installation or billing validation is claimed.

InteroperabilityWell supported
Diehl publishes serial settings, register types, address convention and a complete energy request.2
AccuracyWell supported
The meter is specified for heating and cooling energy measurement, and the module exposes energy, power, flow and temperature values with units.12
SecurityNot yet assessed
The retained serial module guide does not describe authentication or encryption on EIA-485.2
ReliabilitySupported with conditions
The unit and factor registers permit explicit decoding; communication freshness and failed polls must be handled by the client.2
RuggednessSupported with conditions
The compact meter is intended for heating and cooling installations; the module has separate supply and EIA-485 terminals that require correct panel wiring.12
ScalabilitySupported with conditions
Modbus permits unique IDs on a multi-drop EIA-485 bus; automatic IDs must be checked to avoid collisions.2
LifecycleNot yet assessed
The retained public sources do not establish a firmware support period for this optional module.12

Setup

Read the module's first thermal-energy value

Diehl's December 2023 manual gives this complete example for a meter whose serial ends in 026 and whose automatic slave-ID mode therefore selects address 26. Use the installed address rather than copying 26 to another meter.

Function
FC04 Read Input Registers; FC03 Holding Registers also exposes measurement data
Document reference
30001 for energy, 30003 for its factor, 30004 for its unit name and 30008 for its unit code
PDU start and length
Offset 0 (0x0000), 10 registers (0x000A); subtract 30001 from an input-register reference
Example request
Slave 0x1A, function 0x04, start 0x0000, count 0x000A; the manual's complete RTU frame ends CRC 0x73E6
Integer decode
Energy words 0x0000 0x3039 = 12,345 as signed Int32, most significant word and byte first
Unit factor and unit
Factor 0x0001 = 1; ASCII unit MJ; unit code 0x0008 also means MJ
Result
12,345 × 1 MJ = 12,345 MJ = 12.345 GJ in Diehl's worked example

Acceptance: This is Diehl's documented sample frame, not a reading from an EpiSensor installation. On site, read the actual slave and compare the decoded energy and unit with the meter display. Prefer the integer plus unit factor for cumulative energy: Diehl notes that its convenience float can lose display precision.

  1. Identify the module

    Check the SHARKY 775 nameplate and fitted slot module. The separate RS485 M-Bus option is not a Modbus RTU endpoint.

  2. Confirm power and serial wiring

    The Modbus module needs a 12–24 V AC/DC SELV supply on terminals 60/61. Its EIA-485 data terminals are 90 (+) and 91 (-). Follow Diehl's installation instructions and have the panel installer verify the wiring.

  3. Discover the slave

    Start with 9600 bit/s, 8 data bits, no parity and one stop bit if settings are unknown. Automatic addressing is enabled by default and derives the slave ID from the meter's secondary address; read the actual address from the display or commissioning record.

  4. Read energy first

    Use FC04, start 0, count 10. Decode the signed energy integer and its factor and unit, then compare with the front display. Add power, flow and temperature from Diehl's table after this first read agrees.

Common questions

Is every SHARKY 775 a Modbus meter?
No. Modbus RTU is one optional module. Check the fitted module; Diehl also offers M-Bus and other interfaces, including an RS485 module that speaks M-Bus rather than Modbus.1
Why does the energy value differ from the display?
Check the unit and the factor register before converting. Diehl recommends the Int32 value multiplied by its unit factor for cumulative energy because the convenient float representation can lose precision. Also compare readings taken at the same time.2
Is the Modbus slave always address 1?
No. Automatic addressing is enabled by default and can derive the ID from the meter's secondary address. Diehl's example meter ends in 026 and uses slave 26; the installed module may differ.2

Sources

  1. SHARKY 775 ultrasonic thermal energy meter (opens in a new tab) Diehl Metering
  2. Modbus RTU communication module user guide, December 2023 (opens in a new tab) (PDF) Diehl Metering

Further reading

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