What are timers and counters?
What will be an ideal response?
Timers and counters are internal relays. There is no physical timer or counter in the PLC. They are programmed into the logic in the same manner as any other internal relay, by assigning them a number that corresponds to a timer or counter. The difference is that the time delay or number of counts must be programmed when they are inserted into the program. The number of counts for a counter is entered using numbers on the keys on the load terminal. Timers are generally programmed in 0.1-second intervals. Some manufacturers provide a decimal key, whereas others do not. If a decimal key is not provided, the time delay is entered as 0.1-second intervals. If a delay of 10 seconds is desired, for example, the number 100 would be entered. One hundred tenths of a second equals 10 seconds.
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List and describe five different types of energy conversion.
What will be an ideal response?
Answer the following statement(s) true (T) or false (F)
1. A nonconductive optical fiber cable for general-purpose use is marked as Type OFC. 2. The width of the cable tray is equal to the difference between the diameters of the cables. 3. Cable trays containing conductors that operate at over 600 volts are to be clearly marked at regular intervals to indicate that the contents are high-voltage cables. The specific marking is to state “Danger – High Voltage – Keep Away” 4. A single solid aluminum conductor not smaller than 250 kcmil is permitted in the cable, or the conductor is permitted to be formed using up to nineteen 250-kcmil solid aluminum rods laid parallel. 5. A welder is not to be considered as a separately derived premises system.
Design and development that meets the needs of the present without compromising the ability of future generations to meet their own needs is known as
a. resource management. b. environmental protection. c. designing for the future. d. sustainability in design.
Select the agency where an Advance Safety certificate may be earned by safety and health professionals.