⚡ Modbus RTU Integration Guide

Rhoss Chiller

Rhoss Water Chiller Unit — Real-time power, energy and alarm monitoring via Modbus RTU protocol with 6S Teknoloji.

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Monitored Parameters

What Data Do We Read?

Evaporator Inlet Water°C

Evaporator Outlet Water°C

Cooling Load%

Setpoint°C

Compressor Statuson/off

Circuit 1 / Circuit 2 Statusstatus

Pump Statuson/off

Alarm Statuscode

Connection

How to Connect to 6S Teknoloji

Physical Connection

Connect the device to the RS-485 or Ethernet network. Configure Slave ID and baud rate from the device front panel or web interface.

Add Device in 6S Teknoloji

From the 6S web panel click "New Device". Select Rhoss Chiller from the template list — the register map loads automatically.

Live Monitoring

The Field Agent tests the connection; the first readings appear on the dashboard shortly. Alarm thresholds are configured.

Monitored Metrics

What Can You Monitor?

Evaporator inlet/outlet water temperatures
Cooling load percentage and setpoint
Automatic detection of controller family and software version
Per-circuit discharge/suction pressure and superheat
Compressor, cooling circuit and pump statuses
Instant notification of alarm codes
Signed remote setpoint writing with the family-specific register and scale
Correlation of chiller consumption with the energy analyzer

Controller Families

One Register Map Is Not Enough for Rhoss

Under the same brand, different controller families use different address layouts and scaling. Applying one family's map to another yields zeros, -99.99 or physically impossible values; when writing a setpoint it risks the wrong register or the wrong scale (0.8 °C instead of 8 °C). 6S Teknoloji first reads the HR201 (application ID) and HR202 (software version) identity pair on every unit and selects the map accordingly.

Controller	Identity (HR201/HR202)	Key difference
FPV33	Software 6.7	Extensive register + coil map; capacity in per-mille scale (1000 = 100%)
Z-POWER	12 / 59 → software 5.9	Address layout differs from FPV33; the FPV33 map is invalid on this unit
FW 9.4	12 / 94 → software 9.4	Mixed scaling: water temperature and setpoint ×0.01, refrigerant side ×0.1
GZ COMPACT	0 / 0 → identity not readable	Smaller controller; the set point sits in a different register, only measurement-verified points are published

Connection Options

RS-485 directly to the field box serial port: no gateway needed; the field-verified setting is 19200 baud, 8 data bits, no parity, 2 stop bits (8N2).
Several chillers on one RS-485 line are separated by slave address (1, 2, 3…); a single reader polls all units in turn.
If the line is shared with an existing BMS, a Modbus TCP gateway is used. A serial line has only one master at a time; if two programs try to open the same port, their readings lock each other out.

Exporting Rhoss Points to a BMS

Address base: some BMS Modbus drivers (e.g. EcoStruxure EBO) subtract 1 from the entered number before sending it on the line. The number to enter is then HR + 1; otherwise every point shifts by one register.
Commissioning check: give the two cooling setpoints different values; if both look identical on the BMS screen, the addresses are shifted.
On air-cooled units the condenser water registers always return 0; do not define alarms on these points.
Do not define addresses the controller does not support: every read returns an error, the driver retries and occupies the shared line, delaying readings from other devices.

Combined with Chiller Optimisation

The Rhoss integration is at its strongest with rule-based night mode and energy correlation. Details on the chiller optimisation solution page.

Chiller Optimisation →

Also: 6S Teknoloji Platform · York YVAA

FAQ

Frequently Asked Questions

How does a Rhoss chiller connect to 6S Teknoloji?

The Rhoss control board offers Modbus RTU (RS-485) communication. The line can be wired directly to the serial port of the 6S field box (no gateway needed) or reach the Field Agent through a Modbus TCP gateway. Several chillers on the same RS-485 line are separated by slave address.

Which Rhoss values are monitored?

Evaporator inlet/outlet water temperatures, cooling load, setpoint, compressor and circuit statuses, circuit pressures and the alarm code are read. Only points verified by field measurement are published; unverified addresses are left empty instead of inventing values.

Does the same register map work on every Rhoss model?

No. FPV33, Z-POWER (software 5.9), FW 9.4 and GZ COMPACT controllers differ in address layout and scaling. 6S Teknoloji first reads the HR201/HR202 identity pair and selects the matching map; on controllers whose identity cannot be read, only verified points are used.

Can the setpoint be changed remotely?

Yes. The setpoint is written from 6S Teknoloji with a signed, authorized command using the register and scale specific to the controller family; only the defined safe range is accepted and every change goes to the audit trail.

Is alarm flapping (repeated false alarms) prevented?

Yes. A communication outage is not treated as 'no alarm'; alarm decisions use consecutive confirmation (hysteresis). This prevents false alarms and email floods caused by line noise.

Explored Alongside This Device

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Integrate Into Your System

Request a demo; our experts will manage the Rhoss Chiller integration process.