PLC's
PLCs provide rigid control for cycle automation, minimizing ? .
Manual Intervention
Why must technicians wear insulating electrical gloves and use insulated tools and test instruments when working around a PLC?
To protect from electrical shock
A ? switch circuit typically uses a sink or source transistor as the switching device.
3 wire input
A ? PLC typically has 129 I/Os to 512 I/Os.
Medium
Analog signal types include all of the following except ? .
10 mA to 20 mA
PLCs on elevators are loaded with sets of ladder logic instructions that detect ? .
d. the different floors requested and direct the lift to move accordingly
Manufacturers of PLCs often specify a grounding system with a resistance of ? or less.
all the above
What is the programming symbol for an input device (normally closed)?
see picture
? is the section of the operating cycle during which a PLC performs memory management and updates timers and counters.
Housekeeping and overhead
Within the data table files, ? of the files are default files.
9
The output sections of ? PLCs have six relay contacts.
Micro-
Per Occupational Safety and Health Administration (OSHA) standards, equipment is locked out and tagged out before ? .
Preventative Maintenance
Normally open (NO) switches that are ? operated show the operator drawn below the terminals of the switch.
either A or C
A(n) ? device converts one form or level of energy to another form.
Interface
The ? is reserved by the CPU for processing data.
reserved file (file 1)
Extra care must be taken when using a ? command because it overrides all safety features and protocols designed into a program.
Force
In a ? circuit, current stops flowing any time a fuse blows, a circuit breaker trips, or a switch opens.
Series
Any normally open (NO) switch that is ? operated will have the operator of the switch drawn above the terminals of the switch.
Manually
An example of a(n) ? circuit is a two-way switch used to control a lamp.
Digital
A timer instruction consists of three words, each with ? bits.
16
Rack-mounted modules connect to medium or large PLCs through a(n) ? .
Rack enclosure
In most combination circuits, loads such as lights, solenoids, and motors are typically connected in ? .
Parallel
? instructions shift data one bit at a time to earlier or later locations within a PLC program and are entered as “bit shift left,” “bit shift right,” and “copy function.”
File
An example of a(n) ? circuit is a dimmer switch used to control a lamp.
analog
A separate reset (RES) instruction is required to reset a(n) ? instruction.
RTO