Regarding RS485 communication settings of the HDPM6000

[T.Okada]

Hello

I tried configuring the RS485 communication on the HDPM6000,

but I can’t find the settings for parity and stop bits—only the baud rate and ID.

Could you tell me how to change the parity and stop bit settings?

Thanks,

Okada

[Mehran_Mehrnia · Accepted solution]

Hi @T.Okada 

As mentioned in the following FAQ:

HDPM6000 Head Unit default Serial Settings

Default serial port settings:
Unit ID - 1
Parity - None
Stop Bits - 2
Baud Rate - 115200

Parity and stop bit are fixed and embedded in the firmware. Only baud rate and slave ID can be changed.

Best Regards,

-Mehran

L3 Expert Advanced metering

[T.Okada]

Hi @Mehran_Mehrnia,

Thank you for your reply.

I understand they can’t be changed in the current firmware, and I hope the Parity and Stop Bits settings can be made configurable in the next firmware update.

Regards,

Okada

[Mehran_Mehrnia]

Hi @T.Okada 

You're welcome.

At this time, we do not have information regarding changes to these parameters in upcoming firmware releases. The current fixed settings (Parity: None, Stop Bits: 2) are designed to ensure high-speed data integrity for the HDPM6000 platform.

Best Regards,

-Mehran

L3 Expert Advanced metering

[T.Okada]

Hi @Mehran_Mehrnia,

Thank you for explaining why the settings are fixed to Parity: None and Stop Bits: 2.

I understand.

Regards,

Okada

[Mehran_Mehrnia]

Hi @T.Okada 

Following my previous comment, and as verified by the hardware team, the true default serial setting for the HDPM6000 is 8N1.

The HDPM6000 uses the UART driver built into the communications processor. On receive, it never checks for a second stop bit, so it can successfully receive data whether the sender uses one or two stop bits.

The meter is also configured to transmit with only one stop bit. As a result, communication with a polling device configured for 8N2 depends on whether that device strictly requires a full two‑stop‑bit duration for valid reception, or whether it samples only the first stop bit as UARTs typically sample the stop bit once and Modbus RTU provides long idle gaps between characters, the receiver still sees enough HIGH idle time to treat the frame as valid.

The HDPM6000 default serial port settings FAQ will be corrected as:

Unit ID - 1
Parity - None
Stop Bits - 1
Baud Rate - 115200

Best Regards,

-Mehran

L3 Expert Advanced metering