大家好，我們繼續(xù)學習EG系列邊緣計算網(wǎng)關的Node-RED可視化編程，今天要講解的是【DI&DO節(jié)點】。 EG網(wǎng)關自帶若干個DI/DO節(jié)點，DI（數(shù)字輸入）和DO（數(shù)字輸出）節(jié)點通常用于與各種硬件設備進行交互，如傳感器、執(zhí)行器等，下面讓我們一起來學習吧！

DI（數(shù)字輸入）節(jié)點

【DI節(jié)點】

當DI節(jié)點檢測到DI接口的信號有變化時，會主動輸出1/0來表示當前DI接口的狀態(tài)。其中1表示DI檢測到高電平，0表示DI檢測到低電平。

PS：該節(jié)點支持檢測NPN(包括干接點)和PNP。默認支持NPN模式，如需要PNP，請在采購時向客服說明。

【DI節(jié)點】功能

1. 定時刷新狀態(tài)

DI節(jié)點會根據(jù)設置的時間，周期性的刷新當前的DI狀態(tài)。存儲在全局變量“DI_X”中，X為DI的通道號。當然，即使不設置定時刷新，DI如果發(fā)生狀態(tài)變化也會主動更新“DI_X”。

2. 全局變量

在函數(shù)計算如果需要獲DI的當前狀態(tài)，可以使用以下語法獲取：

global.get("DI_1")
#注意1:流程內(nèi)至少存在一個開關量輸入節(jié)點，才會使能開關量輸入的全局變量，才能讀取
#注意2:如果已經(jīng)初始化了全局變量，重啟網(wǎng)關才能刪除全局變量

全局變量可以很直觀的在右側(cè)全局變量窗口查看：

【DI節(jié)點】實操步驟

手動改變DI1口接近開關傳感器的狀態(tài)，觀察結(jié)果。同時通過函數(shù)計算節(jié)點讀取全局變量：

所有的流程支持以json格式導入導出，方便與其他人分享做好的流程。本節(jié)的流程json文件如下，復制后在菜單欄右上角選擇導入粘貼即可，導出同理：

[{"id":"1f3f938edf2e8c81","type":"function","z":"2ff624305b8cb30b","name":"函數(shù)計算 1","func":"msg.payload = global.get(\"DO_1\")\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":390,"y":340,"wires":[["6e804d72c4c1c473"]]},{"id":"b416ef03a7d8eb0d","type":"inject","z":"2ff624305b8cb30b","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":210,"y":340,"wires":[["1f3f938edf2e8c81"]]},{"id":"6e804d72c4c1c473","type":"debug","z":"2ff624305b8cb30b","name":"調(diào)試 2","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":550,"y":340,"wires":[]},{"id":"f25caf631b7b0f87","type":"di","z":"2ff624305b8cb30b","name":"","index":"1","interval":false,"intervalValue":1000,"x":250,"y":220,"wires":[["6ee35db5424a4d26"]]},{"id":"6ee35db5424a4d26","type":"debug","z":"2ff624305b8cb30b","name":"調(diào)試 1","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":470,"y":220,"wires":[]}]

DO（數(shù)字輸出）節(jié)點

【DO節(jié)點】

 可以通過對【DO節(jié)點】寫入1/0或者true/false來實現(xiàn)控制繼電器的吸合或者斷開。

繼電器容量：10A/250VAC 30VDC，即最大可直接承載2500W的用電設備。一般接大功率用電設備時，建議加接觸器或者中間繼電器進行強弱電隔離。

【DO節(jié)點】功能

1. 定時刷新狀態(tài)

DO節(jié)點會根據(jù)設置的時間，周期性的刷新當前的繼電器狀態(tài)。存儲在全局變量“DO_X”中，X為繼電器的通道號。

2. 全局變量

在函數(shù)計算如果需要獲取繼電器的當前狀態(tài)，可以使用以下語法獲?。?/p>

global.get("DO_1")
#注意1:流程內(nèi)至少存在一個繼電器節(jié)點，才會使能繼電器的全局變量，才能讀取
#注意2:如果已經(jīng)初始化了全局變量，重啟網(wǎng)關才能刪除全局變量

全局變量可以很直觀的在右側(cè)全局變量窗口查看：

【DO節(jié)點】實操步驟：

1. 控制繼電器&獲取繼電器狀態(tài)

函數(shù)計算讀取DO_1即第一路繼電器的狀態(tài)，賦值給msg.payload后通過調(diào)試2打印在日志窗口：

json文件：

[{"id":"2dafde0160e2ba6b","type":"do","z":"2ff624305b8cb30b","name":"","index":"1","interval":false,"intervalValue":1000,"x":410,"y":180,"wires":[["a603591f3e178be1"]]},{"id":"6992c0ad230b940b","type":"inject","z":"2ff624305b8cb30b","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"true","payloadType":"bool","x":230,"y":160,"wires":[["2dafde0160e2ba6b"]]},{"id":"a603591f3e178be1","type":"debug","z":"2ff624305b8cb30b","name":"調(diào)試 1","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":570,"y":180,"wires":[]},{"id":"149a0ab24f4c5d8c","type":"inject","z":"2ff624305b8cb30b","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"false","payloadType":"bool","x":230,"y":200,"wires":[["2dafde0160e2ba6b"]]},{"id":"1f3f938edf2e8c81","type":"function","z":"2ff624305b8cb30b","name":"函數(shù)計算 1","func":"msg.payload = global.get(\"DO_1\")\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":410,"y":300,"wires":[["6e804d72c4c1c473"]]},{"id":"b416ef03a7d8eb0d","type":"inject","z":"2ff624305b8cb30b","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":230,"y":300,"wires":[["1f3f938edf2e8c81"]]},{"id":"6e804d72c4c1c473","type":"debug","z":"2ff624305b8cb30b","name":"調(diào)試 2","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":570,"y":300,"wires":[]}]

2. 全局變量

函數(shù)計算讀取DO_1即第一路繼電器的狀態(tài)，如果此時流程內(nèi)沒有繼電器輸出節(jié)點，則會提示未定義：

小提示：

使用接觸器或者中間繼電器時，建議增加滅弧器，來消除感性負載在失電時產(chǎn)生的感生電能對電路產(chǎn)生的干擾，保護設備穩(wěn)定長壽命工作。

結(jié)語

今天的分享結(jié)束了，以上就是EG系列邊緣計算網(wǎng)關可視化編程教程【DI/DO節(jié)點】的全部內(nèi)容，EG系列邊緣計算網(wǎng)關是可支持Node-RED編程的邊緣計算網(wǎng)關，硬件節(jié)點包含DI/DO/AI/AO/串口/OTA/SYS/GPS/CAN等！我們期待下期再見！