According to the actual requirements of the data acquisition terminal of the automatic feeding mixer truck and considering the universality of the module, the technical indexes of the terminal are determined as follows.

（1）模塊工作電壓：本終端的工作電壓來源于車載電瓶，通常為 12V 或者24V，模塊電壓應(yīng)小于電源電壓；

(1) Module working voltage: the working voltage of this terminal comes from the on-board battery, usually 12V or 24V, and the module voltage shall be less than the power supply voltage;

（2）通訊方式：可采用無線網(wǎng)絡(luò)和短信息方式通訊；

(2) Communication mode: wireless network and short message communication can be adopted;

（3）終端在線率：為了確保終端與監(jiān)控中心數(shù)據(jù)交流的實(shí)時(shí)性，終端應(yīng)保持高在線率；

(3) Terminal online rate: in order to ensure the real-time data exchange between the terminal and the monitoring center, the terminal shall maintain a high online rate;

（4）丟包率：丟包率是指測(cè)試中，所丟失數(shù)據(jù)包數(shù)量占所發(fā)送數(shù)據(jù)包的比率，為了降低數(shù)據(jù)丟包率，在設(shè)計(jì)中可以考慮，發(fā)生無線傳輸模塊不能連接網(wǎng)絡(luò)，導(dǎo)致終端不能登錄系統(tǒng)的情況時(shí)，待無線傳輸模塊脫離盲區(qū)后，將數(shù)據(jù)補(bǔ)傳至服務(wù)器；

(4) Packet loss rate: the packet loss rate refers to the ratio of the number of lost packets to the transmitted packets during the test. In order to reduce the packet loss rate, it can be considered in the design that when the wireless transmission module cannot connect to the network, resulting in the terminal unable to log in to the system, the data will be transmitted to the server after the wireless transmission module leaves the blind area;

（5）定位精確度：車輛監(jiān)控調(diào)度系統(tǒng)的電子地圖精度數(shù)量級(jí)是米，我國二級(jí)道路的標(biāo)準(zhǔn)寬度為 30~60m，如果要對(duì)車輛進(jìn)行準(zhǔn)確的監(jiān)控，定位精度需控制在30m 以內(nèi)，否則，當(dāng)兩條道路的距離過近時(shí)，就可能出現(xiàn)定位錯(cuò)誤，即正在某條公路上行駛的車輛被定為在道路外或其它道路上。

(5) Positioning accuracy: the order of magnitude of the electronic map accuracy of the vehicle monitoring and dispatching system is meters. The standard width of the secondary road in China is 30 ~ 60m. If you want to accurately monitor the vehicles, the positioning accuracy needs to be controlled within 30m. Otherwise, when the distance between the two roads is too close, positioning errors can occur, that is, the vehicles driving on a certain road are determined to be outside the road Or other roads.