problem: the project needs to develop 485 serial communication on the android panel. The serial port needs to be monitored after the read command is sent, and the communication is not considered to have failed after N time. Use java s FutureTask with F...
recently, after writing a PLC communication protocol, I sent it a command to read 1 byte after the address 0x0000 (the address 0x0000 exists in PLC, and sent successfully, and the data sent is correct), it should send me 12 bytes (including ACK, site nu...
problem description Open two serial ports at the same time in Android environment, one of them receives the instruction and sends the instruction to the other, but the command of the second serial port will block and often return garbled or the two in...
is using RXTX to write its own communication protocol. At present, one of the problems encountered is: a sends data to B, assuming that the header data of frame I received by B fails to pass, and B requires A to resend, so how can I correctly deal with ...
how to get Service, in the Job class of Quartz and Service is Null in the Job class. found several methods on the Internet but did not solve it. The code is below. Please take a look at it. error message java.lang.NullPointerException at com.wuf...
function validform() { return $("-sharpreset_passwd").validate({ rules: { password: { required: true, minlength: 6 }, confirm_password: { required: true, minlength: 6, ...
the kibana and elasticsearch-head corresponding to the higher version of elasticsearch are developed by nodejs, and the startup is also started through the command npm run start of nodejs but after startup, how to determine whether the service is star...
The business scenario is as follows: I provide a ws server A for client B to call. Each call, the client inserts a piece of data into the database tab and then submits it. My server An internally calls another server C, and passes this data to the serve...
this is my code const Koa=require( koa ); const http=require( http ); const https=require( https ); const app=new Koa(); const fs = require( fs ); const enforceHttps = require( koa-sslify ); const config = require( . config ); const option...