Chapter 1 electro mecha device part 2
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1) Solid state timers use electronic devices to provide time delays and are encapsulated in epoxy resin for protection but cannot be repaired. 2) Programmable timers have timing functions included in devices like PLCs and can maintain or not maintain accumulated time when input is interrupted. 3) On delay timers have a preset time period that must pass after energization before any action occurs and timer contacts do not change position until the set time passes.
Chapter 1 electro mecha device part 2
- 1. Type of timer…cont 3) Solid state timer -time delay provided by solid state electronic device. -design as plug in module. -not suitable for outside environmental usage since it is encapsulate in epoxy resin for more protection. -since it is encapsulate, impossible to repair.
- 2. Type of timer…cont 4) Programmable timer - is a timer (timing function) included in electrical devices such PLCs - Retentive timer -maintain its current accumulated time when its control input is interrupted. - Non retentive timer -Do not maintain its current accumulated time value when its control input signal is interrupted.
- 3. Timing Function There is several timing function is available inside the timers. 1) On Delay 2) Off Delay 3) One shot
- 4. On Delay (delay on operate) timer -Has a preset time period that must been passed after the timer has been energized before any action occur. -On delay timer contact do not change position until the set time period passes after the timer receive power. -Once activated, it maybe ON or OFF the load.
- 5. Example application of On Delay -maybe use to monitor patient breathing -timer use to sound alarm if patient not take a breath within 10 sec. -The circuit includes a low pressure actuated switch build into patient monitoring system. -Low Pressure switch will activate if the pressure less than 1 psi (6kPA),means the patient start not breathing. -Means, the timer start timing and continues until patient takes a breath (which reset the timer).