The invention relates to device diagnostics in industrial processes comprising field devices employing a field bus. A remote diagnostics device (1) is placed in connection with a process device (2), separate from the field devices and the field bus. The remote diagnostics device comprises diagnostics electronics which collects diagnostics data relating to the process device, and a transmitter part for wireless (17) transmission of the diagnostics data to a near-by field device. The field device comprises a receiver part (41) for wireless (17) reception of the diagnostics data from said remote diagnostics device (1). A field device control unit (430) analyses the received diagnostics data and transmits a diagnostics report over a field bus interface (44) and the field bus to a diagnostics computer.