Hi Graeme,

The issue you describe was not able to be replicated on our test dosers while running both SA and SLAVE on firmware 1.28.

Normally after the slave doser has been assigned to the SA unit, the PAB green light will be solid. This indicates normal function. The amber LED will flash when there is communication occurring between the SA and Slave doser.

Have you tried using the other PAB port on the units while on FW 1.28?