CyberCertPrepOT Security FundamentalsOT Fundamentals: Network Architecture & ProtocolsEASYFree question
A control engineer must open a valve by writing a single on or off bit in a Modbus device. Which function code writes one coil?
- A.Code 02 writes one discrete input to its new state
- B.Code 04 writes one coil from an input register
- C.Code 05 forces one coil to its on or off state
- D.Code 06 writes one coil through a holding register
Why C is correct
Function code 5 is Write Single Coil. Code 6 writes one 16-bit holding register, code 2 only reads discrete inputs, and code 4 only reads input registers, so none of those can set a coil.
Know someone studying for OT Security Fundamentals? Send them this one.