The pump does not answer on Modbus. What should I check?

Check that the CIF-Module Modbus RTU is seated in the module slot and that bus address, baud rate and data frame in the pump menu match ModbusCloud. Parameter A sets the baud rate (5 = 9600, 6 = 19200) and parameter C the frame (2 = 8N1). Then swap A and B and check the termination switch on the module.

Reads are one register off. What is wrong?

Wilo lists raw addresses as they go on the bus. The Wilo setup example therefore reads register 700 and tells you to try 699 or 701 only if a master adds an offset. This template uses the raw addresses unchanged, so no offset is needed.

Why is the temperature around 290 instead of 20 degrees?

Wilo reports temperatures in kelvin with a scale of 0.1. A read value of 2931 means 293.1 K, which is 20 °C. Subtract 273.15 to get degrees Celsius; the template keeps the kelvin unit from the Wilo document.

Heating power and energy stay empty. Why?

The heat meter registers from 300 need CIF module firmware 3.00 or later and the heat meter function set up on the pump with its temperature sensors. Check CIF Firmware Version: the main version is in the high byte, so 768 means 3.00.

Can I switch the pump on or change the setpoint?

Not with this template: it only reads. The CIF module does offer holding registers for pump command, control mode and setpoint, but writing them overrides the pump settings and the bus command timer can lock the local pump menu or load fallback values. Leave control to the building automation or the pump itself.

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Modbus RTU

Wilo Stratos MAXO

Name: Wilo Stratos MAXO
Brand: Wilo
SKU: 646444b7-bb37-46fe-be9e-67d3e58bb047

Wilo

Smart circulator pump: pressure, flow, power, temperature, heat energy and error codes over Modbus RTU with the Wilo CIF module.

Overview

The Wilo Stratos MAXO is a smart glandless circulator pump for heating, cooling and air conditioning, also as twin pump (MAXO-D) and for drinking water (MAXO-Z). With the Wilo CIF-Module Modbus RTU it reports pressure, flow, power, speed, temperature, energy and its error status over RS485. This template follows the Wilo functional description of the CIF-Module Modbus RTU (document wilo194406) and reads 19 input registers: pressure, estimated flow, power input, speed, fluid temperature, energy consumption, operating time, pump status, error and service bit fields, the error code, and heat meter values. Default link in the Wilo example: address 1, 9600 baud, 8 data bits, no parity, 1 stop bit.

Key readings

Pressure and estimated flow
Power input and speed
Fluid temperature
Energy consumption and operating time
Pump status and error bit fields
Error code as on the display
Heating and cooling power and energy

Use cases

Alert when Error Type or Error Message is not equal to 0, so a stopped circulator in a heating loop is noticed quickly.
Track Power Input and Flow per pump to find circulators that run harder than the system needs.
Log Heating Energy Total and Cooling Energy Total per group for an energy report without a separate heat meter.
Compare Flow Temperature and Return Temperature to check the temperature difference over a heating or cooling circuit.
Plan service from Operation Time and alert on Service Message when the pump asks for maintenance.

Installation

1Fit the Wilo CIF-Module Modbus RTU in the module slot of the Stratos MAXO and connect A and B to the RS485 port of your ModbusCloud Gateway. Switch on the 120 ohm termination at the last device of the bus.
2In the pump menu, set the bus address, baud rate (parameter A, 5 = 9600) and data frame (parameter C, 2 = 8N1). The Wilo example uses address 1, 9600 baud and 8N1.
3In ModbusCloud, add a Modbus device (RTU) with the same address, baud rate and data frame, and import this template.
4Check the link: CIF Firmware Version must return a value such as 512 (version 2.00) and Power Input must match the pump display. If nothing answers, swap A and B and check the bus address.

Things to watch for

The pump does not answer on Modbus. What should I check?: Check that the CIF-Module Modbus RTU is seated in the module slot and that bus address, baud rate and data frame in the pump menu match ModbusCloud. Parameter A sets the baud rate (5 = 9600, 6 = 19200) and parameter C the frame (2 = 8N1). Then swap A and B and check the termination switch on the module.
Reads are one register off. What is wrong?: Wilo lists raw addresses as they go on the bus. The Wilo setup example therefore reads register 700 and tells you to try 699 or 701 only if a master adds an offset. This template uses the raw addresses unchanged, so no offset is needed.
Why is the temperature around 290 instead of 20 degrees?: Wilo reports temperatures in kelvin with a scale of 0.1. A read value of 2931 means 293.1 K, which is 20 °C. Subtract 273.15 to get degrees Celsius; the template keeps the kelvin unit from the Wilo document.
Heating power and energy stay empty. Why?: The heat meter registers from 300 need CIF module firmware 3.00 or later and the heat meter function set up on the pump with its temperature sensors. Check CIF Firmware Version: the main version is in the high byte, so 768 means 3.00.
Can I switch the pump on or change the setpoint?: Not with this template: it only reads. The CIF module does offer holding registers for pump command, control mode and setpoint, but writing them overrides the pump settings and the bus command timer can lock the local pump menu or load fallback values. Leave control to the building automation or the pump itself.

Registers (19)

19 read / 0 write

Name	Address	Function	Type	Unit	Access
Pressure Actual pump pressure in cm H2O (raw value x 10), 0 to 65534, 65535 = error. Differential or absolute depending on sensor, calculated on sensorless types. Wilo name Pressure.	•••	•••	•••		R
Flow Estimated flow in m³/h (raw x 0.1), 0 to 9998, 9999 = error. Wilo name Flow (estimated).	•••	•••	•••	m³/h	R
Power Input Electrical power input in W, 0 to 65534, 65535 = error. Wilo name power input.	•••	•••	•••	W	R
Speed Motor speed of the master pump in 1/min, 0 to 65534, 65535 = error. Wilo name Speed.	•••	•••	•••	rpm	R
Fluid Temperature Fluid temperature at the pump in kelvin (raw x 0.1), 65535 = error. Subtract 273.15 for °C. Wilo name temperature fluid @ device.	•••	•••	•••	K	R
Energy Consumption Electrical energy consumption of the pump in kWh, 0 to 65534, 65535 = error. Wilo name Energy Consumption.	•••	•••	•••	kWh	R
Operation Time Operating time of the master pump in h (raw x 10), 0 to 65534, 65535 = error. Wilo name Operation Time.	•••	•••	•••	h	R
Pump Status Pump status bit field. Bit 0 = pump on, bit 2 = setpoint not reached; other bits in the Wilo description of register 38.	•••	•••	•••		R
Error Type Error type bit field. Bit 0 = electronic module error, bit 1 = motor error, bit 3 = error present (motor stopped, restart will follow), bit 4 = supply voltage error. 0 = no error.	•••	•••	•••		R
Error Message Error message bit field, bit 0 = undervoltage; other bits in the Wilo description of register 37. 0 = no error.	•••	•••	•••		R
Service Message Service message bit field, bit 0 = service required; other bits in the Wilo description of register 35.	•••	•••	•••		R
User Trouble Code Error code as shown on the pump display, 0 = no error (for example 401 = voltage fluctuations in mains). CIF module firmware 3.00 or later.	•••	•••	•••		R
Heating Power Heating power delivered through the pump (heat meter function), REAL in W. CIF module firmware 3.00 or later. Wilo name power heating.	•••	•••	•••	W	R
Cooling Power Cooling power delivered through the pump (heat meter function), REAL in W. CIF module firmware 3.00 or later. Wilo name power refrigeration.	•••	•••	•••	W	R
Heating Energy Total Total heating energy, REAL in kWh. CIF module firmware 3.00 or later. Wilo name Energy heating total.	•••	•••	•••	kWh	R
Cooling Energy Total Total cooling energy, REAL in kWh. CIF module firmware 3.00 or later. Wilo name Energy refrigeration total.	•••	•••	•••	kWh	R
Flow Temperature Fluid temperature in the forward line in kelvin (raw x 0.1). Subtract 273.15 for °C. CIF module firmware 3.00 or later.	•••	•••	•••	K	R
Return Temperature Fluid temperature in the return line in kelvin (raw x 0.1). Subtract 273.15 for °C. CIF module firmware 3.00 or later.	•••	•••	•••	K	R
CIF Firmware Version Firmware version of the CIF module, main version in the high byte (512 = 2.00). Useful to check the connection.	•••	•••	•••		R

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