Applies To:
  • CitectSCADA 5.xx

I have some Momentum I/O that supports Ethernet and the MODBUS/TCP specification (see KB article Q2605).  I want to use Citect with it - can I use the Citect MODNET driver? 

No, the Momentum Ethernet option is not supported by Citect.  Whilst the protocol that the device uses is supported by Citect's MODNET driver, the device's operating characteristics are different to a standard PLC.  Therefore, the MODNET driver is unsuitable for use with the Momentum I/O.

There are no current plans to support the Momentum I/O directly in Citect.  Users should interface the Momentum I/O to an appropriate controller, and then communicate to that controller with Citect.

Footnote: The "operating characteristics" referred to include:

- the failsafe mode on outputs, such that the driver must continually write to the outputs within a certain time period.  The driver does not do this, as it polls on demand.

- multiplexing of inputs & outputs are also not supported.