The my-PV AC•THOR and AC•THOR 9s are photovoltaic power managers that convert surplus solar power into hot water or space heating by steplessly controlling resistive loads such as immersion heaters. The AC•THOR controls up to 3,000 W in operating mode M1 (6,000 W in M3 with the relay output); the AC•THOR 9s has three outputs and controls up to 9,000 W in M1 (18,000 W in M3, from firmware a0020500). TapHome communicates with the device over Modbus TCP on port 502 and writes the heating power directly, so a TapHome automation can route the measured PV surplus into the hot water tank instead of exporting it to the grid.
The template exposes the power command as a writable device, the hot water temperature and the current heating power (with its solar and grid portions) as readouts, and the device status together with electrical values as service diagnostics.
Hardware connection
Installation of the AC•THOR must be carried out by an accredited specialist according to the manufacturer’s assembly instructions. Only pure resistive loads may be connected (immersion heaters, boilers, convectors, heating mats, infrared panels) — never units with an electronic power supply or electronic thermostats. For heating water, only heaters with an integral safety temperature limiter may be connected.
The AC•THOR receives external control signals over the IP protocol through its Ethernet RJ45 port. Connect it with a standard network cable (CAT5 or CAT7) to the same router or switch as the TapHome Core.
The overview below shows the connection area of the AC•THOR 9s (labels in German: Verbraucheranschlüsse = load outputs OUT-1 to OUT-3, Ethernet RJ45, SD Card Slot, 4 Temp. Sensoren = four temperature sensors, Schaltkontakt 16A = 16 A switch contact, Netzanschluss 3 × 230 V = mains input). The connection area of the single-output AC•THOR differs.
Network connection
In the manufacturer’s diagram for control by an energy management system, the AC•THOR is connected over its RJ45 port to the router, and the energy management system — in this case the TapHome Core — is connected to the same router. TapHome then sends the target power to the AC•THOR over this network.
Hot water and temperature sensor
The Hot Water Temperature device reads temperature sensor 1 of the AC•THOR. The my-PV digital temperature sensor is supplied with the device; mount it in a thermowell — never immerse it directly in water — and clarify its position with the tank manufacturer. Up to four digital sensors can be connected to the AC•THOR 9s.
The example below shows operating mode M1 (hot water) with one three-phase immersion heater of up to 9 kW on the AC•THOR 9s.
If no my-PV temperature sensor is used, a bimetallic thermostat is required on the immersion heater. The neutral conductor must not be wired through a switch. The AC•THOR 9s requires 3 × 230 V with neutral conductor, protected by at most 16 A per phase (tripping characteristic B or C).
Configuration
Network and IP address
DHCP is active by default, so the AC•THOR receives its IP address from the router. The current address is shown on the device display in the status information (IP) and in the DHCP list of the router.
Because TapHome connects to a fixed address, assign a static IP address in the device’s general settings (IP DHCP/static, then IP address, subnet mask, gateway and DNS server), or create a DHCP reservation in the router. The static settings must match the router’s network, otherwise the device becomes invisible in the network.
Opening the web interface
From Ethernet firmware a0020000, the web interface is an external HTML file:
- Enter the IP address of the AC•THOR in a web browser. The page shows a download link for the web interface file.
- Save the file locally and open it — or open the web interface directly from the link on that page.
- In installations without internet access, download the HTML file in advance.
Alternatively, the my-PV Scanner program (part of the AC•THOR software package on the my-PV website) finds the devices in the network; a double click on the search result opens the web interface. If several my-PV devices are present, identify the unit by its serial number on the type plate. The scan uses UDP port 16124, which a firewall or router setting may block.
my-PV does not recommend making the AC•THOR reachable from the internet through port forwarding. TapHome only needs access in the local network.
Enabling Modbus TCP control
- In the web interface, open Control Settings and select the control type Modbus TCP. The control type can also be chosen on the display during commissioning or in the settings under Control.
- The control type can only be selected on a device with device number 1 (the factory default, the master). If the unit has a different number, set it back to 1 first.
- Select the operating mode for the application — for example M1 Hot water — and the temperature sensor for that mode.
- Optionally adjust the Power timeout in the device settings (10–600 s). It defines how long the last power command stays valid when no new command arrives.
Without the control type Modbus TCP, the AC•THOR does not accept power commands written to register 1000.
On firmware up to a0010103, changing the communication and control settings on the display may require a higher access level protected by a password; see the my-PV operating instructions.
Communication parameters
| Parameter | Value |
|---|---|
| Protocol | Modbus TCP |
| Port | 502 |
| Modbus Slave ID (template default) | 1 |
| Register type | Holding registers (read 0x03, write 0x06 / 0x10) |
| Data format | 16-bit integers (unsigned; the meter power in register 1069 is signed) |
| Register addresses | “Real” addresses as documented by my-PV |
The complete register list is provided by my-PV on request.
my-PV allows each writable register to be written at most once a day to protect the lifespan of the non-volatile memory. The power command (register 1000) is exempt from this limit, together with a few other registers (clock, boost activation and the extended power registers). The template therefore writes only the power command — setpoints, boost, legionella protection and time settings belong on the device display or in the web interface.
In TapHome, add a Modbus TCP interface, import the template and enter the IP address of the AC•THOR.
Device capabilities
Surplus power control
- Power Target — the commanded heating power in watts (H:1000). A TapHome automation typically computes the available PV surplus from an electricity meter and writes it to this device; the AC•THOR converts it steplessly into heat. The value range is 0–3,000 W (AC•THOR, M1) or 0–9,000 W (AC•THOR 9s, M1). The command expires after the device’s power timeout, so the template re-sends it periodically.
Temperature and power monitoring
- Hot Water Temperature — water temperature measured by sensor 1, in 0.1 °C resolution (H:1001).
- Heating Power — electrical power currently delivered by this AC•THOR to its loads (H:1082, shown in kW). The service attributes Solar part of heating power (H:1083) and Grid part of heating power (H:1084) split it into the PV and grid portions in W. These registers are available from firmware a0020303.
Diagnostics
Service attributes on the module show:
| Attribute | Register | Meaning |
|---|---|---|
| Operating status | H:1003 | Off (0), Starting up, Operation (9), Power stage error (200 and above) |
| Voltage L1 | H:1061 | Grid voltage on L1 in V |
| Current L1 | H:1062 | Current on L1 in A (0.1 A resolution) |
| Grid frequency | H:1064 | Grid frequency in Hz |
| Grid meter power | H:1069 | Power at the metering point in W, negative values mean feed-in |
| Maximum power currently possible | H:1071 | Maximum power the device can take at the moment in W, including slaves |
A power stage error (status code 200 and above) is also raised as a module error in TapHome.
Troubleshooting
- The device does not react to power commands — check that the control type is set to Modbus TCP. Any other control type ignores register 1000. If the control type cannot be changed, check that the device number is 1.
- No external control in operating mode M3 — in M3, an AC•THOR without an available load at the controllable output cannot be controlled externally over Modbus TCP. Check the load and its thermostat or safety temperature limiter.
- Heating stops after a short while even with surplus available — the power command expires after the power timeout (10–600 s). Make sure the TapHome connection is alive so that the command is refreshed, or increase the power timeout on the device.
- Register addresses appear shifted by one — my-PV documents “real” register addresses. Some Modbus clients add 1 to the address (for example 1001 instead of 1000); if readings look misaligned, check the address offset of the client.
- Heating Power or its solar and grid parts do not show values — registers 1082–1084 exist from firmware a0020303. Check the firmware version in the status information on the display and update the device.
- Hot Water Temperature shows 0 °C or 85 °C — the manufacturer uses 0 ° for a broken probe and 85 ° for a data disruption of the temperature sensor. Check sensor 1 and its wiring.
- Status shows “Power stage error” — status codes of 200 and above indicate an error state of the power stage. Error messages are shown only on the home screen of the device display, not in the web interface.
- The AC•THOR cannot be found in the network — read the IP address on the display or in the router’s DHCP list; a firewall may block the my-PV Scanner on UDP port 16124. After switching to a static IP, check that address, subnet mask and gateway match the router.
