modbus

Two 16 bit ints to One 32 bit float value

随声附和 提交于 2020-01-07 04:37:19
问题 I am able to extract values from modbus as 16-bit shorts (unsigned) or as ints (should be treated as 16-bit words). I am tasked to combine two values to create a single 32 bit float value using java. some example values I observed using a gui program: int + int = float 0 + 16256 = 1 0 + 17096 = 100 0 + 17097 = 100.5 0 + 17530 = 1000 8192 + 17530 = 1000.5 I attempted bit wise operators but that didn't seem to do the trick. leaves me scratching my head! 回答1: You can use Float.intBitsToFloat(int

NModbus4 read TXT from PLC

时光总嘲笑我的痴心妄想 提交于 2020-01-07 02:01:09
问题 I'm programming a Click PLC with a C# application with NModbus4. (RS232) Now i'm trying to read and write TXT data. This is the code and result: When I check the Click PLC software I can see that for each two chars one Modbus address is used. How can I get the text saved in the PLC? Someone got an idea? The text stored in the PLC is "Dit is tekst" 回答1: A Modbus register is 16-bit wide, so it can store two chars. This is why each two chars share the same address. That said, you need to infer

compiling a program that includes libmodbus in C

℡╲_俬逩灬. 提交于 2020-01-06 08:31:38
问题 I am a newbie in C... I wrote a very simple modbus1.c that includes libmodbus (whose source I downloaded, unzipped, untarred, ./configure'd, make'd and make install'd successfully). When I try to make modbus1.c I get this: cc -Wall -g modbus1.c -o modbus1 Undefined symbols for architecture x86_64: "_modbus_close", referenced from: _main in modbus1-6cd135.o "_modbus_connect", referenced from: _main in modbus1-6cd135.o "_modbus_free", referenced from: _main in modbus1-6cd135.o "_modbus_new_tcp

How do you communicate to a Modbus device within an iPhone application?

蹲街弑〆低调 提交于 2020-01-04 06:28:30
问题 I would like to be able to develop an iPhone application that can communicate with Modbus devices, but I'm not sure how to proceed. Has anyone had experience with this or are there existing libraries out there for this purpose? 回答1: You will need first to know how to make a simple TCP client on your iPhone, and a simple TCP server on your computer that your iPhone client will talk to via WiFi. Make sure PING command works and firewall does not block your server port before any client/server

Lua: Working with Bit32 Library to Change States of I/O's

有些话、适合烂在心里 提交于 2020-01-03 02:51:11
问题 I am trying to understand exactly how programming in Lua can change the state of I/O's with a Modbus I/O module. I have read the modbus protocol and understand the registers, coils, and how a read/write string should look. But right now, I am trying to grasp how I can manipulate the read/write bit(s) and how functions can perform these actions. I know I may be very vague right now, but hopefully the following functions, along with some questions throughout them, will help me better convey

ModbusTCP协议

青春壹個敷衍的年華 提交于 2019-12-30 18:06:59
【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 原文链接: https://blog.csdn.net/iknow_nothing/article/details/84292914 简介 Modbus由MODICON公司于1979年开发,是一种工业现场总线协议标准。1996年施耐德公司推出基于以太网TCP/IP的Modbus协议:ModbusTCP。 Modbus协议是一项应用层报文传输协议,包括ASCII、RTU、TCP三种报文类型。 标准的Modbus协议物理层接口有RS232、RS422、RS485和以太网接口,采用master/slave方式通信。 ModbusTCP数据帧 ModbusTCP的数据帧可分为两部分: MBAP + PDU 。 报文头MBAP MBAP为报文头,长度为7字节,组成如下: 事务处理标识 协议标识 长度 单元标识符 2字节 2字节 2字节 1字节 内容 解释 事务处理标识 可以理解为报文的序列号,一般每次通信之后就要加1以区别不同的通信数据报文。 协议标识符 00 00表示ModbusTCP协议。 长度 表示接下来的数据长度,单位为字节。 单元标识符 可以理解为设备地址。 帧结构PDU PDU由 功能码+数据 组成。功能码为1字节,数据长度不定,由具体功能决定。 功能码 Modbus的操作对象有四种:线圈、离散输入

pymodbus: request creation and response receiving

孤者浪人 提交于 2019-12-30 11:14:33
问题 Can anyone explain how to create the request and get the response in right way using pymodbus via Modbus TCP/IP? I have the PLC wich I want to use as slave and PC - as master. I trying to do it in such way: from pymodbus.client.sync import ModbusTcpClient host = '192.168.56.9' port = 502 client = ModbusTcpClient(host, port) client.connect() #Register address 0x102A (4138dec) with a word count of 1 #Value - MODBUS/TCP Connections #Access - Read #Description - Number of TCP connections request

How to resolve ModbusSlaveException: Error Code = 3?

╄→尐↘猪︶ㄣ 提交于 2019-12-25 16:39:18
问题 I am having a modbus project where i am getting error code 3 while reading from device. If anyone knows what is the problem and how to resolve please help out. net.wimpi.modbus.ModbusSlaveException: Error Code = 3 回答1: Exception code 3 is "Illegal value", and it means that one of the values you provided in the request is illegal. This won't be an invalid address as that is exception code 2 ("Illegal address"). Which means that most likely your count of registers to read is either less than or

modbus rtu over tcp (modbus tcp gateway)

狂风中的少年 提交于 2019-12-24 18:23:41
问题 Is it possible to build a modbus-RTU ethernet gateway using a linux box or arduino? I have plc slaves linked together using modbus RTU, and I want to connect one of them over TCP with my pc as master. I wonder if I can use a linux box (rasbery pi/raspbian) connected to a router, as a modbus-to-tcp converter by piping the usb port to my local ip on some port, as one plc will be connected in modbus rtu to the linux box`s usb port. Piping command will be something Like this: nc -l 5626 > /dev

Python script for RTU Modbus Slave

梦想与她 提交于 2019-12-24 16:05:21
问题 I am working on a automation test case for a system and need a automated modbus input device. My use case here is to implement a Raspberry pi based RTU modbus slave and connected to a modbus master. I want this raspberry pi based slave to populate and send a response to master when ever master requests for a register value. I am new to this protocol and environment, I am not able to find any python script or libraries where we have a modbus slave client. I came across this below Serial python