ECU-C: Power limit value accepted locally (HA + webpage) but not enforced on inverters — only EMA App works

[JeffRenard]

Related to #125 and possibly the same root cause as #151.

Setup: ECU-C, ID 21500006xxx, firmware ECU-C-Z_C1.2.26, integration v2.15.0.

Symptom: Setting number.roof_ecu_21500006xxxx_power_limit via HA is accepted end-to-end:

HA logs confirm success: Response from ECU on bridging zero export to state open: Set Switch successfully
The ECU-C's own local page (/index.php/meter/meter_func1) reflects the new value correctly.
But actual inverter output is not curtailed — current_power stayed at 330W with a 70W limit set (checked several minutes after, well past the 5-minute inverter update cycle).
Confirmed twice: once during a real Zero Export need (target ~70W, grid stayed at -1500W), once with a clean manual test.
Setting the exact same value through the EMA App (cloud) works and curtails output immediately.

Question: Is this consistent with the webinterface deprecation affecting not just data display but actual enforcement logic on the ECU-C side? Is there a known firmware version where this still works correctly, to help narrow down when the regression happened?

Happy to share full debug logs if useful.

[HAEdwin]

Please submit a ticket to APsystems. They are very willing to maintain compatibility with Home Assistant until the full Modbus replacement is available. It also raises awareness that compatibility with Home Assistant is very important for many APsystems users.

[JeffRenard]

ok

[TheNetworker69]

Some news about recent problem on grid value ?

[HAEdwin]

Nope, my guess is that the team first priority was to work on the APmeter and P1 dongle, compatibility for EMA energy management and export power control with hybrid RS485 and LAN meter. It is noteworthy that the ECU-B previously supported a maximum of 4 panels, but that is 16 panels now.

[JeffRenard]

As usual, APS didn't reply despite a follow-up; they really aren't very cooperative. Jeff. Le ven. 18 sept. 2026, 12:52, HAEdwin ***@***.***> a écrit :

…

Nope, my guess is that the team first priority was to work on the APmeter and P1 dongle, compatibility for EMA energy management and export power control with hybrid RS485 and LAN meter. It is noteworthy that the ECU-B previously supported a maximum of 4 panels, but that is 16 panels now. — Reply to this email directly, view it on GitHub <#163?email_source=notifications&email_token=BQVU5YQEWODLLN37BX3GWJD5PUHXNA5CNFSNUABIM5UWIORPF5TWS5BNNB2WEL2ENFZWG5LTONUW63SDN5WW2ZLOOQXTCOBUHE4TAMBVUZZGKYLTN5XKMYLVORUG64VFMV3GK3TUVRTG633UMVZF6Y3MNFRWW#discussioncomment-18499005>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BQVU5YSOTS5ZVSZX6FIESKD5PUHXNAVCNFSNUABIKJSXA33TNF2G64TZHM4DSMRZHA4TINJWHNCGS43DOVZXG2LPNY5TCMBXHE3DGNJTUF3AE> . You are receiving this because you authored the thread.Message ID: <HAEdwin/homeassistant-apsystems_ecu_reader/repo-discussions/163/comments/18499005 @github.com>