PLC test review
Ladder logic in PLCs - Answer-used to detect floor requests and direct elevator movement
wire management - Answer-terminal blocks are used to manage wire connections between PLC I/O and
electrical devices/ components
overheating risk - Answer-A PLC can overheat and become a fire hazard
force command - Answer-extra care is required when using force command as it overrides all safety
features and protocols in a program
grounding - Answer-electronic equipment grounding reduces electrical noise in PLCs, process control
equipment,
arc rated clothing - Answer-clothing must insulate heat, resist ignition, and withstand break open forces
from an arc
emergency stops - Answer-PLC controlled systems must include a sufficient number of emergency stops
NPN input devices - Answer-NPN transistor type input devices connect the PLC input between the
positive terminal of the supply voltage and the collectors of the switch/ sensor
parallel loads - Answer-total resistance is less than the lowest resistance of any load : total current
equals the sum of currents through all loads
NO switches - Answer-Normally open switches are mechanically or automatically operated
, AND logic circuits - Answer-input devices for AND logic circuits include any number of normally open
switches connected in series
Byte - Answer-a group of 8 bits
housekeeping and overhead - Answer-section of the PLC cycle for memory management and updating
timers/ counters
input scan - Answer-PLC examines input devices for voltage presence or absence and records a 0 or 1 at
the corresponding input data table location
electronic system - Answer-use either analog or digital electrical signals
interface device function - Answer-does not multiply the number of available input contacts
analog circuit example - Answer-a dimmer switch controlling a lamp
default files - Answer-nine files are default within the data table files
reserved file - Answer-reserved by the cpu for the processing data (file 1 )
program files - Answer-three program files are always used: system file (file 0) , reserved file (file 1), and
main program file (file 2)
output placement - Answer-output components are place in parallel
Ladder logic in PLCs - Answer-used to detect floor requests and direct elevator movement
wire management - Answer-terminal blocks are used to manage wire connections between PLC I/O and
electrical devices/ components
overheating risk - Answer-A PLC can overheat and become a fire hazard
force command - Answer-extra care is required when using force command as it overrides all safety
features and protocols in a program
grounding - Answer-electronic equipment grounding reduces electrical noise in PLCs, process control
equipment,
arc rated clothing - Answer-clothing must insulate heat, resist ignition, and withstand break open forces
from an arc
emergency stops - Answer-PLC controlled systems must include a sufficient number of emergency stops
NPN input devices - Answer-NPN transistor type input devices connect the PLC input between the
positive terminal of the supply voltage and the collectors of the switch/ sensor
parallel loads - Answer-total resistance is less than the lowest resistance of any load : total current
equals the sum of currents through all loads
NO switches - Answer-Normally open switches are mechanically or automatically operated
, AND logic circuits - Answer-input devices for AND logic circuits include any number of normally open
switches connected in series
Byte - Answer-a group of 8 bits
housekeeping and overhead - Answer-section of the PLC cycle for memory management and updating
timers/ counters
input scan - Answer-PLC examines input devices for voltage presence or absence and records a 0 or 1 at
the corresponding input data table location
electronic system - Answer-use either analog or digital electrical signals
interface device function - Answer-does not multiply the number of available input contacts
analog circuit example - Answer-a dimmer switch controlling a lamp
default files - Answer-nine files are default within the data table files
reserved file - Answer-reserved by the cpu for the processing data (file 1 )
program files - Answer-three program files are always used: system file (file 0) , reserved file (file 1), and
main program file (file 2)
output placement - Answer-output components are place in parallel
