The intrinsically safe, SIL2 Display Trip Amplifier type ABBD2 is a panel mounting large colour display that may also be used as a trip amplifier for local 4-20mA or an outbye remote trip amplifier using Austdac SILBUS field bus network. The local or remote 4-20mA input is converted, to display gas levels (or any other levels i.e. air flow), as a percentage or parts per million (ppm).