This page lists the different WattNode Module Modbus (WND series) firmware versions and release notes. The WattNode Meter Module for Modbus meter may be field upgraded or returned to the factory for firmware updates. We recommend against firmware upgrades unless necessary to fix a bug or for an essential new feature. There is a nominal charge for firmware updates unless they are needed to fix a bug under warranty. This page does not list every firmware change, but only those likely to affect customers. Some changes are to enhance production or internal diagnostics.
Reference Manual: WND-Module-Modbus-Ref-Manual.pdf
Register List: WattNode Meter Module Register List FW1028.xls
Firmware version 1028 is the second public firmware version for the WattNode Meter Module. Version 1027 was a beta test version that was not publicly released. The following list of changes includes all updates since firmware version 1026.
- BUG: Fix a firmware bug that could cause a stuck RS-485 transmit enable. If this occurs, the Meter Module transmits continuously, blocking all communication on the RS-485 network until the meter is power cycled. In version 1026 firmware, this bug could be triggered in two ways:
- Heavy Modbus traffic at 115,200 baud.
- Violations of the Modbus RTU protocol, in particular if the bus master fails to honor the required silent interval between message frames or if the bus master transmits when the WattNode meter should be responding to a request.
- BUG: ErrorStatusQueue always reported 0 (no error). Only the ErrorStatus1 – ErrorStatus8 registers reported error. ErrorStatusQueue now reports errors like the WNC series meters and is non-volatile as described in the manual.
- BUG: Fixed a bug where changes to the ReplyDelay register did not take effect until other communications configuration registers were changed and saved, or the meter was rebooted.
- UPDATE: Update the ErrorStatus1 – ErrorStatus8 registers to match the WNC series, so errors are non-volatile (not preserved if the meter loses power or resets). Instead, the ErrorStatusQueue register is non-volatile.
- UPDATE: Update the RS-485 logic to remove some collision detection logic. This improves performance at high baud rates. A properly functioning Modbus RTU network should never have collisions unless two devices are configured to have the same slave address. More specifically, there are two types of collision detection, one of which was removed:
- The meter will detect if another slave device starts responding to a request from the master before the meter starts responding. This logic is still included.
- Check for collisions while transmitting bytes of data. This logic was removed, in part because it did not reliably detect collisions and in part because it introduced high processing overhead.
- UPDATE: Add 24 hour LED error indication (all LEDs red for 24 hours) for severe errors. This matches the WNC behavior and increases the likelihood that an installer or operator will notice a serious error.
- UPDATE: Remove support for the ModbusMode register and TCP-RTU mode to simplify the Modbus implementation and improve performance. The ModbusMode register will always report a value of 0. Writes are still allowed, but will be ignored.
- UPDATE: Allow CtAmps values up to 30000. The previous limit was 6000.
- UPDATE: To reduce false positives, excessive DC offset warnings for the CT and line voltage inputs are reported only after multiple consecutive instances of detecting the excessive offset.