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)時器(qi)的(de)(de)作(zuo)(zuo)用主要是幫助(zhu)人們準確(que)控制時間,也能起到備忘的(de)(de)作(zuo)(zuo)用,通過定(ding)時器(qi)設定(ding)好時間,以便提示(shi)自(zi)己在(zai)規定(ding)的(de)(de)時間做某些事情,并在(zai)適當時間轉換事宜,比如(ru)玩多久手機就去(qu)工作(zuo)(zuo)或學習等(deng)。
2、除此之外,隨著技術的進(jin)步,定時器(qi)(qi)也廣(guang)泛應用(yong)于各種生活(huo)電(dian)器(qi)(qi),如開水(shui)機(ji)、熱水(shui)器(qi)(qi)的定時控制,空調的定時開關等,設置在電(dian)器(qi)(qi)上(shang)的定時器(qi)(qi)能使電(dian)器(qi)(qi)定時開機(ji)、定時關機(ji),實(shi)現節能、安全、健康的使用(yong)。
3、定(ding)時(shi)(shi)器(qi)還能(neng)應用于軍事方面,比如定(ding)時(shi)(shi)炸彈、定(ding)時(shi)(shi)雷(lei)管等都是(shi)通過定(ding)時(shi)(shi)器(qi)來控制的(de)。
二、定時器的種類有哪些
起初(chu)的定(ding)時器是(shi)利(li)用機械鐘帶動開關的,隨(sui)著(zhu)定(ding)時器的發展,也(ye)有(you)了許多不同(tong)的種類,那(nei)么定(ding)時器有(you)哪些種類呢?根據不同(tong)的原理和工作(zuo)類型(xing),定(ding)時器可分(fen)為:
1、斷開延時型定時器
這種定(ding)時(shi)器是當(dang)輸入條件(jian)00000為ON時(shi)無延(yan)時(shi)作用,只有在(zai)輸入條件(jian)00000為OFF時(shi)產生延(yan)時(shi)作用。它在(zai)SIEMENS的PLC中又被稱為SF型(xing)定(ding)時(shi)器。
2、接通延時型定時器
接通延(yan)時(shi)(shi)型定(ding)時(shi)(shi)器(qi)是各種PLC中常見的(de)基本的(de)定(ding)時(shi)(shi)器(qi),這種定(ding)時(shi)(shi)器(qi)在 SIEMENS的(de)PLC中,稱(cheng)為SD型定(ding)時(shi)(shi)器(qi)。
3、保持型接通延時定時器
這種定(ding)時(shi)器(qi)又稱(cheng)SS型定(ding)時(shi)器(qi),是當輸(shu)入條件00000為ON后,即產(chan)生鎖存功能,即使輸(shu)入條件00000又變為OFF,仍視(shi)輸(shu)入條件為ON,當定(ding)時(shi)器(qi)的當前(qian)值(zhi)等于設定(ding)值(zhi)時(shi),定(ding)時(shi)器(qi)動作。
4、脈沖型定時器
這(zhe)種定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)是(shi)當輸(shu)入(ru)條件00000為(wei)ON后(hou),定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)即(ji)時(shi)(shi)動作,但經過定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)所設定(ding)(ding)(ding)(ding)的(de)(de)時(shi)(shi)間(jian)(jian)后(hou),即(ji)使輸(shu)入(ru)條件00000仍為(wei)ON,定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)卻變為(wei)OFF狀態(tai)(tai)。即(ji)這(zhe)種定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)ON狀態(tai)(tai)的(de)(de)維(wei)持(chi)時(shi)(shi)間(jian)(jian)是(shi)由設定(ding)(ding)(ding)(ding)值決定(ding)(ding)(ding)(ding)的(de)(de)。如果00000為(wei)ON的(de)(de)時(shi)(shi)續(xu)時(shi)(shi)間(jian)(jian)小于定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)的(de)(de)設定(ding)(ding)(ding)(ding)值,定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)的(de)(de)ON狀態(tai)(tai)維(wei)持(chi)時(shi)(shi)間(jian)(jian)為(wei)輸(shu)入(ru)條件00000為(wei)ON的(de)(de)持(chi)續(xu)時(shi)(shi)間(jian)(jian)。這(zhe)種定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)在SIEMENS的(de)(de)PLC中,稱(cheng)為(wei)SP型定(ding)(ding)(ding)(ding)時(shi)(shi)器(qi)。
5、擴張型脈沖定時器
這(zhe)種定(ding)時(shi)(shi)(shi)(shi)器(qi)與脈沖型定(ding)時(shi)(shi)(shi)(shi)器(qi)的區別是,只要輸入條(tiao)件00000出現了ON狀態(tai),不管其持(chi)(chi)續時(shi)(shi)(shi)(shi)間多長(chang),均可使定(ding)時(shi)(shi)(shi)(shi)器(qi)為ON的維持(chi)(chi)的時(shi)(shi)(shi)(shi)間與定(ding)時(shi)(shi)(shi)(shi)器(qi)的設定(ding)值一致(zhi)。這(zhe)種定(ding)時(shi)(shi)(shi)(shi)器(qi)在(zai)SIEMENS的PLC中,稱為SE型定(ding)時(shi)(shi)(shi)(shi)器(qi)。