Fans, drainage pumps and drives of tunnel equipment work far from the operators, so emergency stop and guard monitoring must reach where cabling is difficult. The UF 6925 module of the SAFEMASTER family disconnects the safety circuit on a two-channel signal from buttons and guard switches, with cross-fault detection and outputs on forcibly guided contacts.
The SAFEMASTER W wireless system carries the emergency stop and guard signals over radio between two UH 6900 modules or between a module and the RE 6900 handheld transmitter; the transmission is bidirectional with link quality monitoring, and loss of the link switches off the circuit on the receiving side. The datasheets give Category 4 / PL e to EN ISO 13849-1 and SIL 3 for both products.
Selection of the radio system requires a range check in the tunnel structure - metal walls and structures attenuate the signal - according to the antenna selection and positioning note, and validation of the system according to EN ISO 13849-2.
