Monitor 重錘測(cè)料位6-8531-1122可直接查面價(jià)
MONITORAvailable since 1.0.0.
MONITOR is a debugging command that streams back every command processed by the Redis server. It can help in understanding what is happening to the database. This command can both be used via redis-cli and via telnet.
The ability to see all the requests processed by the server is useful in order to spot bugs in an application both when using Redis as a database and as a distributed caching system.
$ redis-cli monitor
1339518083.107412 [0 127.0.0.1:60866] "keys" "*"
1339518087.877697 [0 127.0.0.1:60866] "dbsize"
1339518090.420270 [0 127.0.0.1:60866] "set" "x" "6"
1339518096.506257 [0 127.0.0.1:60866] "get" "x"
1339518099.363765 [0 127.0.0.1:60866] "del" "x"
1339518100.544926 [0 127.0.0.1:60866] "get" "x"
Use SIGINT (Ctrl-C) to stop a MONITOR stream running via redis-cli.
$ telnet localhost 6379
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
MONITOR
+OK
+1339518083.107412 [0 127.0.0.1:60866] "keys" "*"
+1339518087.877697 [0 127.0.0.1:60866] "dbsize"
+1339518090.420270 [0 127.0.0.1:60866] "set" "x" "6"
+1339518096.506257 [0 127.0.0.1:60866] "get" "x"
+1339518099.363765 [0 127.0.0.1:60866] "del" "x"
+1339518100.544926 [0 127.0.0.1:60866] "get" "x"
QUIT
+OK
Connection closed by foreign host.
Manually issue the QUIT or RESET commands to stop a MONITOR stream running via telnet.
Commands not logged by MONITOR
Because of security concerns, all administrative commands are not logged by MONITOR's output.
Furthermore, the following commands are also not logged:
AUTH
EXEC
HELLO
QUIT
Cost of running MONITOR
Because MONITOR streams back all commands, its use comes at a cost. The following (totally unscientific) benchmark numbers illustrate what the cost of running MONITOR can be.
Benchmark result without MONITOR running:
$ src/redis-benchmark -c 10 -n 100000 -q
PING_INLINE: 101936.80 requests per second
PING_BULK: 102880.66 requests per second
SET: 95419.85 requests per second
GET: 104275.29 requests per second
INCR: 93283.58 requests per second
Benchmark result with MONITOR running (redis-cli monitor > /dev/null):
$ src/redis-benchmark -c 10 -n 100000 -q
PING_INLINE: 58479.53 requests per second
PING_BULK: 59136.61 requests per second
SET: 41823.50 requests per second
GET: 45330.91 requests per second
INCR: 41771.09 requests per second
In this particular case, running a single MONITOR client can reduce the throughput by more than 50%. Running more MONITOR clients will reduce throughput even more.
Return value
Non standard return value, just dumps the received commands in an infinite flow.
History
>= 6.2: RESET can be called to exit monitor mode.
>= 6.0: AUTH excluded from the command's output.
Related commands
Monitor 重錘測(cè)料位6-8531-1122可直接查面價(jià)
安裝在料倉(cāng)頂部的料位計(jì)傳感器的探測(cè)過(guò)程由控制顯示儀表發(fā)出的信號(hào)控制。傳感器由可逆電機(jī)、蝸輪、蝸桿、絲杠、齒輪軸、繞線筒、靈敏杠桿等組成。(見(jiàn)圖2)
當(dāng)傳感器接到探測(cè)命令時(shí):電機(jī)正轉(zhuǎn),經(jīng)蝸輪、蝸桿減速后帶動(dòng)齒輪軸和繞線筒轉(zhuǎn)動(dòng),使鋼絲繩下放,帶動(dòng)重錘由倉(cāng)頂下降。當(dāng)重錘降至料面時(shí)被料面托起而失重,鋼絲繩松馳,靈敏杠桿動(dòng)作使
微動(dòng)開(kāi)關(guān)接觸,控制顯示器得到該信號(hào)立即發(fā)出電機(jī)反轉(zhuǎn)命令,重錘上升返回,直到繞線筒碰上到頂開(kāi)關(guān),電機(jī)停轉(zhuǎn),重錘回到倉(cāng)頂
原始位置,完成一次探測(cè)過(guò)程。
在此過(guò)程中控制顯示儀表通過(guò)檢測(cè)繞線筒的轉(zhuǎn)數(shù)計(jì)算出重錘從倉(cāng)底到料面間的距離,在面板進(jìn)行數(shù)字顯示,并在后面板端子上輸出4~20mA電流。
重錘式料位計(jì)可用來(lái)測(cè)量粉狀、顆粒狀及塊狀固體物料料倉(cāng)的料位,使用戶可靠地掌握料倉(cāng)中的料位。
產(chǎn)品概述
重錘式料位計(jì)用于監(jiān)測(cè)料斗、筒倉(cāng)、儲(chǔ)罐等容器內(nèi)粉末、顆粒和液體高度或近似重量的實(shí) 時(shí)測(cè)量。它通過(guò)直接測(cè)量頂部無(wú)料空間距離,間接達(dá)到測(cè)量料層內(nèi)物料高度的目的,并且可以根據(jù)不同的工況選擇配置各種法蘭、重錘及操作界面或遠(yuǎn)程通訊等,實(shí) 現(xiàn)了人性化、科學(xué)化、合理化的設(shè)計(jì)宗旨。其中QHYC-Ⅰ系列用于冶金行業(yè)的料位測(cè)量,QHLC-Ⅰ系列用于糧油加工業(yè)的料位測(cè)量。
工作原理
重錘式料位計(jì)的主要部件有:重錘、安裝法蘭、測(cè)量機(jī)構(gòu)、吹灰裝置、導(dǎo)向輪、鋼絲繩、鋼絲繩卷筒、擺桿機(jī)構(gòu)、控制單元、電機(jī)、測(cè)控單元、計(jì)量單元和電氣接口。
傳 感器接到探測(cè)命令時(shí),電機(jī)正轉(zhuǎn),經(jīng)減速機(jī)構(gòu)后帶動(dòng)繞線筒轉(zhuǎn)動(dòng),鋼纜下放,重錘跟隨其下降,當(dāng)重錘降至料面時(shí)被料面托起而失重,鋼絲繩松馳,靈敏杠桿動(dòng)作使 霍爾元件動(dòng)作,并將位置信號(hào)傳遞給控制器,控制器得到該信號(hào)后立即發(fā)出電機(jī)反轉(zhuǎn)命令,重錘隨鋼絲繩上升返回,直到重錘回到倉(cāng)頂原始位置,電機(jī)停轉(zhuǎn),完成一 次探測(cè)過(guò)程。 并以4—20mA電流信號(hào)、標(biāo)準(zhǔn)的MODBUS串行通訊方式、干接點(diǎn)三種方式傳輸給DCS系統(tǒng)或外置顯示單元料位及報(bào)警信號(hào)。
Monitor 重錘測(cè)料位6-8531-1122可直接查面價(jià)