ZHCSK86 September 2019 THVD1505
PRODUCTION DATA.
External biasing resistor network of RFS along with RT define the VFS during the polarity correction time, tFS. See Passive Polarity Definition Using Fail-Safe Biasing Network for more details.
RFS resistors should be selected such that VFS > |VIT| = 100 mV. The equation below can be used to calculate RFS. Note that too low of a RFS value increases the bus loading that reduces the number of nodes on the RS-485 bus.