一、定時器是干什么用的
定時器是一種用于定時和計時的機械或電子裝置,類似鬧鐘,發明于1876年,在此之前,人們通常會用沙漏或水漏進行定時或計時,那么定時器有什么用呢?
1、定時(shi)器的(de)(de)作用主要是幫助人(ren)們準確(que)控制時(shi)間,也能起(qi)到備(bei)忘的(de)(de)作用,通過(guo)定時(shi)器設定好時(shi)間,以便提(ti)示自己在(zai)規定的(de)(de)時(shi)間做(zuo)某些事(shi)情,并在(zai)適當時(shi)間轉換事(shi)宜,比如玩多久(jiu)手機就去工作或學習(xi)等。
2、除此之外,隨著技術的進步,定(ding)時(shi)器(qi)也(ye)廣(guang)泛應用于各種生(sheng)活(huo)電器(qi),如(ru)開(kai)水機(ji)、熱(re)水器(qi)的定(ding)時(shi)控制,空調的定(ding)時(shi)開(kai)關等(deng),設(she)置在電器(qi)上的定(ding)時(shi)器(qi)能使電器(qi)定(ding)時(shi)開(kai)機(ji)、定(ding)時(shi)關機(ji),實現節能、安全、健康(kang)的使用。
3、定時(shi)器還能應(ying)用于軍事方面,比如定時(shi)炸彈、定時(shi)雷管(guan)等都是通過(guo)定時(shi)器來(lai)控(kong)制的(de)。
二、定時器的種類有哪些
起初的定(ding)時(shi)器是利用機(ji)械鐘帶動(dong)開關的,隨著定(ding)時(shi)器的發展,也有了許多不同的種(zhong)類,那(nei)么定(ding)時(shi)器有哪些種(zhong)類呢?根據(ju)不同的原理和工作(zuo)類型(xing),定(ding)時(shi)器可分為:
1、斷開延時型定時器
這種定(ding)時(shi)(shi)器是當(dang)輸入(ru)(ru)條件(jian)00000為ON時(shi)(shi)無延時(shi)(shi)作用(yong),只有(you)在輸入(ru)(ru)條件(jian)00000為OFF時(shi)(shi)產生延時(shi)(shi)作用(yong)。它(ta)在SIEMENS的PLC中(zhong)又被稱為SF型定(ding)時(shi)(shi)器。
2、接通延時型定時器
接通延時(shi)(shi)(shi)型定時(shi)(shi)(shi)器(qi)是各種PLC中常見的(de)基本的(de)定時(shi)(shi)(shi)器(qi),這種定時(shi)(shi)(shi)器(qi)在 SIEMENS的(de)PLC中,稱為SD型定時(shi)(shi)(shi)器(qi)。
3、保持型接通延時定時器
這(zhe)種定(ding)時器(qi)又稱SS型定(ding)時器(qi),是當輸入(ru)條(tiao)件00000為(wei)ON后,即產生鎖存功能,即使輸入(ru)條(tiao)件00000又變為(wei)OFF,仍視輸入(ru)條(tiao)件為(wei)ON,當定(ding)時器(qi)的當前值等于設定(ding)值時,定(ding)時器(qi)動作。
4、脈沖型定時器
這種(zhong)(zhong)定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)(qi)(qi)是(shi)當(dang)輸入(ru)條件(jian)00000為(wei)(wei)ON后,定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)(qi)(qi)即時(shi)(shi)動(dong)作(zuo),但(dan)經過定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)(qi)(qi)所設(she)定(ding)(ding)(ding)(ding)的(de)時(shi)(shi)間(jian)(jian)后,即使輸入(ru)條件(jian)00000仍為(wei)(wei)ON,定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)(qi)(qi)卻變為(wei)(wei)OFF狀(zhuang)(zhuang)態(tai)。即這種(zhong)(zhong)定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)(qi)(qi)ON狀(zhuang)(zhuang)態(tai)的(de)維持時(shi)(shi)間(jian)(jian)是(shi)由設(she)定(ding)(ding)(ding)(ding)值(zhi)決定(ding)(ding)(ding)(ding)的(de)。如果00000為(wei)(wei)ON的(de)時(shi)(shi)續時(shi)(shi)間(jian)(jian)小于定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)(qi)(qi)的(de)設(she)定(ding)(ding)(ding)(ding)值(zhi),定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)(qi)(qi)的(de)ON狀(zhuang)(zhuang)態(tai)維持時(shi)(shi)間(jian)(jian)為(wei)(wei)輸入(ru)條件(jian)00000為(wei)(wei)ON的(de)持續時(shi)(shi)間(jian)(jian)。這種(zhong)(zhong)定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)(qi)(qi)在SIEMENS的(de)PLC中,稱為(wei)(wei)SP型定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)(qi)(qi)。
5、擴張型脈沖定時器
這種(zhong)定(ding)(ding)(ding)時(shi)器(qi)(qi)與脈沖型(xing)定(ding)(ding)(ding)時(shi)器(qi)(qi)的(de)區別(bie)是,只(zhi)要輸入(ru)條件00000出現了ON狀態(tai),不(bu)管(guan)其持(chi)續時(shi)間(jian)(jian)多長,均可(ke)使定(ding)(ding)(ding)時(shi)器(qi)(qi)為(wei)ON的(de)維(wei)持(chi)的(de)時(shi)間(jian)(jian)與定(ding)(ding)(ding)時(shi)器(qi)(qi)的(de)設定(ding)(ding)(ding)值一致。這種(zhong)定(ding)(ding)(ding)時(shi)器(qi)(qi)在SIEMENS的(de)PLC中,稱為(wei)SE型(xing)定(ding)(ding)(ding)時(shi)器(qi)(qi)。