Askoma Askoma
The Askoma ASKOHEAT+ is a multi-level immersion heating element for buffer tanks and boilers, designed to convert surplus PV or renewable electricity into stored heat. The ModbusCloud template communicates over Modbus TCP and reads active power consumption and measured tank temperature, reads back the configured temperature setpoint, and writes the feed-in power setpoint at address 202 to control Power-to-Heat operation. This gives installers and energy managers real-time visibility and remote control of thermal storage in a single cloud-connected template.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 5, read and write
- Brand
- Askoma
- Last updated
Registers (5)
4 read, 1 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| active_power | W | Read | |||
| temperature_setpoint | °C | Read | |||
| temperature | °C | Read | |||
| target_active_power_a | W | Read | |||
| target_active_power_b | W | Write |
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Use cases
- Monitor active power consumption in real time to verify the ASKOHEAT+ is absorbing the expected PV surplus.
- Track measured tank temperature over time to confirm thermal storage is reaching the configured setpoint.
- Alert on measured temperature remaining below the setpoint for an extended period to catch sensor or heater faults.
- Write the feed-in power setpoint via address 202 from the portal to dynamically adjust Power-to-Heat loading.
- Compare logged active power against grid feed-in data to verify excess energy is being redirected to heat storage.
Installation
Connect the ASKOHEAT+ to your local LAN via its RJ45 port and assign a static IP address in your router so the device address does not change between sessions.
Open the ASKOHEAT+ web interface at http://askoheat.local or the assigned IP address, and confirm Modbus TCP is active on port 502 under the communication or Modbus section.
In your ModbusCloud portal, add the ModbusCloud Gateway to the same network segment as the ASKOHEAT+, import the Askoma template, and set the unit ID to match your device (default 1).
Spot-check register 110 (active_power) in the portal live-data view while the heater is running to confirm non-zero watt readings and that polling is working correctly.
Things to watch for
The gateway connects but active_power always reads zero. Why?
Register 110 reports the actual heater load only when at least one heating element is switched on. If no control input is active, the value is legitimately zero. Verify the heater step or feed-in setpoint is non-zero and that the safety thermostat has not tripped.
Values disappear from the portal after about a minute. What is happening?
The ASKOHEAT+ clears command registers including the feed-in setpoint after 60 seconds of Modbus TCP silence. Ensure the ModbusCloud Gateway maintains a continuous polling interval and that no firewall is dropping idle TCP connections between polls.
Writing to target_active_power_b has no effect. What should I check?
Address 202 expects a signed int16 written with function code 16. Negative values engage Power-to-Heat mode; positive values cause the device to switch off automatically. Confirm the value sent is negative and that firmware version 4.2.1 or higher is installed, as this register requires that minimum version.
Is it safe to write large negative values to the feed-in setpoint register?
Use caution when writing to target_active_power_b (address 202). Sending values beyond the rated heater capacity has no effect on power but abrupt or repeated writes can cause rapid relay cycling. The ASKOHEAT+ includes a switch-on inhibit to protect relay contacts, but always verify setpoints match your installation's rated power before automating writes.
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