Does anyone know of a good (preferably open source) library for dealing with the Modbus protocol? I have seen a few libraries, but I am looking for some people's personal experiences, not just the top ten Google hits. I figure there has to be at least one other person who deals with PLCs and automation hardware like I do out there. Open...
Has anyone successfully talked profibus from a .NET application? If you did, what device/card did you use to accomplish this, what was the application, and did you use any kind of preexisting or available code? ...
Where is a good place to start with making an application in .NET that communicates through OPC? ...
We all know the various ways of testing OO systems. However, it looks like I'll be going to do a project where I'll be dealing with PLC ladder logic (don't ask :/), and I was wondering if there's a good way of testing the validity of the system. The only way I see so far is simply constructing a huge table with all known states of the s...
How do I learn PLC programming? Would it differ greatly for different brands of PLCs? Is ladder programming the same as PLC programming? ...
I have a requirement for porting some existing C code to a IEC 61131-3 compliant PLC. I have some options of splitting the code into discrete function blocks and weaving those blocks into a standard solution (Ladder, FB, Structured Text etc). But this would require carving up the C code in order to build each function block. When l...
Are pointers safe against online change of running PLC program in TwinCAT 2.10 and in CoDeSys 2.3 on which the first one is based? What happens if memory block gets reallocated as part of online program change and there are pointers pointing to that memory block? ...
Hello guys! The company I am doing my intership/appretinceship in, does mainly PLC programming with Siemens modules. Comes from the fact that most of the people were electric guys and switched over to engineering. My problem as newbie there is, that I can't be really efficient and fast when I code PLC software. Even though I am very e...
I am trying to use PLC's to monitor a race track. I will be using 3 Photo sensors to show which car crossed the finish line first. Each sensor will have be OTL (Latched) instruction. Each lane will have a light to indicate which car was in first place. The car not in first lights will not come. There will be 3 judges. At the completiono...
Hi Folks, I'm afraid I'm not making much progress on the 3S forums. So you lot are going to get pestered now! I'm using 3S Codesys v2.3 I'm trying to create a boot project and do sourcecode download on my build server and I'd like to avoid having any hardware plugged into it. I'm using the following command line to run Codesys: Bui...
On a single ladder rung how many outputs can you have. If you have more than one. Would it be AND Logic, or OR Logic. Series, or parallel. I'm trying to make six lights flash using timer on delay instructions with a closed input instruction. I will using an Allen Bradley SLC 500 series PLC. ...
How do you determine direction of inputs using ladder diagrams with a PLC? Meaning, how do you save the previous state? Previous state of inputs. I need to determine direction that photobeams were activated.. forward or reverse. If they are activated in reverse, perform one action. If they are activated forwards, perform a different act...
Hi, I need to develop a simple website to display some values that are inputted to a PLC connected to a hardware Gateway( HMS AnyBus AB7007) already installed that converts RS485 Modbus to Ethernet Modbus TCP/IP. I am developing my code using .Net (C Sharp) As I am quite a novice in PLC interfacing, is there a component, AcitiveX co...
I am looking to use 'Packet Loss Concealment' to conceal lost PCM frames in an audio stream. Unfortunately, I cannot find a library that is accessible without all the licensing restrictions and code bloat (...up for some suggestions though). I have located some GPL code written by Steve Underwood for the Asterisk project which implemen...
Can an input X1 change while instruction sequence is still being processed? e.g. LD X1 AND X2 OUT Y1 LD X1 // Can X1 loaded here differ from the previous one? AND X3 OUT Y1 Thanks ...
Hi All Can I Write Programs for PLC Controlling in C Sharp? How? ...
I'm running this code to connect to a plc. System.Guid guid=new Guid("75d00bbb-dda5-11d1-b944-9e614d000000"); System.Type t=Type.GetTypeFromCLSID(guid,node,true); object COMobject=System.Activator.CreateInstance(t); opcServer = (IOPCServer) COMobject; using the opc protocol as previously mentioned. I have little to no ex...
Hi all, I am doing a project with a PLC, im using sockets to interact with server listening on the PLC.I gave the instructions in the ASCII Format,untill 127 my instructions are working fine,when it exceeds 127 ,the code works but proper values are not sent to the PLC . how to overcome this. s= 130; Query = Convert.ToChar(00).ToString...