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(ding)(ding)時(shi)(shi)(shi)(shi)器的作(zuo)用(yong)(yong)主要是幫助(zhu)人(ren)們準確控制(zhi)時(shi)(shi)(shi)(shi)間(jian),也能起(qi)到備忘的作(zuo)用(yong)(yong),通過定(ding)(ding)時(shi)(shi)(shi)(shi)器設定(ding)(ding)好時(shi)(shi)(shi)(shi)間(jian),以便提示自己在(zai)規(gui)定(ding)(ding)的時(shi)(shi)(shi)(shi)間(jian)做某些事情,并在(zai)適當(dang)時(shi)(shi)(shi)(shi)間(jian)轉換事宜,比(bi)如玩(wan)多久手機就去(qu)工作(zuo)或學(xue)習等。
2、除此之外(wai),隨(sui)著技術的(de)進步,定(ding)時(shi)(shi)器也廣泛(fan)應(ying)用(yong)于各種生活電器,如(ru)開(kai)(kai)水機(ji)、熱水器的(de)定(ding)時(shi)(shi)控(kong)制,空調的(de)定(ding)時(shi)(shi)開(kai)(kai)關等,設置在電器上的(de)定(ding)時(shi)(shi)器能(neng)使電器定(ding)時(shi)(shi)開(kai)(kai)機(ji)、定(ding)時(shi)(shi)關機(ji),實現節能(neng)、安全、健康的(de)使用(yong)。
3、定時(shi)(shi)器(qi)還能應(ying)用(yong)于軍事(shi)方(fang)面,比(bi)如定時(shi)(shi)炸彈、定時(shi)(shi)雷(lei)管(guan)等都是通過定時(shi)(shi)器(qi)來(lai)控制的。
二、定時器的種類有哪些
起初的(de)定時器(qi)是(shi)利用機械鐘帶動(dong)開關的(de),隨著定時器(qi)的(de)發展,也有了許(xu)多(duo)不(bu)同的(de)種類(lei),那么定時器(qi)有哪些種類(lei)呢?根據不(bu)同的(de)原理和工作類(lei)型(xing),定時器(qi)可分為:
1、斷開延時型定時器
這種(zhong)定時(shi)(shi)器是當輸入條件(jian)00000為ON時(shi)(shi)無延(yan)時(shi)(shi)作用,只(zhi)有在輸入條件(jian)00000為OFF時(shi)(shi)產生延(yan)時(shi)(shi)作用。它(ta)在SIEMENS的(de)PLC中(zhong)又(you)被稱為SF型定時(shi)(shi)器。
2、接通延時型定時器
接通延時(shi)型(xing)(xing)定(ding)(ding)時(shi)器是各種(zhong)PLC中常(chang)見的基本的定(ding)(ding)時(shi)器,這種(zhong)定(ding)(ding)時(shi)器在 SIEMENS的PLC中,稱為SD型(xing)(xing)定(ding)(ding)時(shi)器。
3、保持型接通延時定時器
這(zhe)種(zhong)定(ding)時器(qi)又(you)稱SS型定(ding)時器(qi),是當輸(shu)入條(tiao)件00000為ON后(hou),即產生鎖存功能,即使輸(shu)入條(tiao)件00000又(you)變為OFF,仍視輸(shu)入條(tiao)件為ON,當定(ding)時器(qi)的(de)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(zhe)(zhe)種(zhong)(zhong)定(ding)時(shi)(shi)(shi)(shi)器(qi)是當輸入(ru)(ru)條(tiao)(tiao)件(jian)(jian)00000為ON后,定(ding)時(shi)(shi)(shi)(shi)器(qi)即時(shi)(shi)(shi)(shi)動作,但經(jing)過定(ding)時(shi)(shi)(shi)(shi)器(qi)所設定(ding)的(de)(de)時(shi)(shi)(shi)(shi)間(jian)后,即使輸入(ru)(ru)條(tiao)(tiao)件(jian)(jian)00000仍為ON,定(ding)時(shi)(shi)(shi)(shi)器(qi)卻變為OFF狀(zhuang)態。即這(zhe)(zhe)種(zhong)(zhong)定(ding)時(shi)(shi)(shi)(shi)器(qi)ON狀(zhuang)態的(de)(de)維(wei)持時(shi)(shi)(shi)(shi)間(jian)是由設定(ding)值決定(ding)的(de)(de)。如(ru)果(guo)00000為ON的(de)(de)時(shi)(shi)(shi)(shi)續時(shi)(shi)(shi)(shi)間(jian)小于定(ding)時(shi)(shi)(shi)(shi)器(qi)的(de)(de)設定(ding)值,定(ding)時(shi)(shi)(shi)(shi)器(qi)的(de)(de)ON狀(zhuang)態維(wei)持時(shi)(shi)(shi)(shi)間(jian)為輸入(ru)(ru)條(tiao)(tiao)件(jian)(jian)00000為ON的(de)(de)持續時(shi)(shi)(shi)(shi)間(jian)。這(zhe)(zhe)種(zhong)(zhong)定(ding)時(shi)(shi)(shi)(shi)器(qi)在SIEMENS的(de)(de)PLC中,稱為SP型定(ding)時(shi)(shi)(shi)(shi)器(qi)。
5、擴張型脈沖定時器
這種定(ding)時(shi)器(qi)與脈沖型定(ding)時(shi)器(qi)的區別是,只要(yao)輸入條件00000出現了ON狀(zhuang)態,不管其持(chi)續時(shi)間多長,均可使定(ding)時(shi)器(qi)為ON的維持(chi)的時(shi)間與定(ding)時(shi)器(qi)的設定(ding)值(zhi)一致。這種定(ding)時(shi)器(qi)在(zai)SIEMENS的PLC中,稱(cheng)為SE型定(ding)時(shi)器(qi)。