Modbus communication with Modicon premium PLC

Is it possible to communicate modicon premium plc(P574634M) and Lab view through modbus.
If possible how?

First, do a search for Modbus. There are several options available for communicating with Modbus devices from LV.
Then, if you have a more specific question, you can post it to the LabVIEW board (you posted to the feedback board by accident).
Try to take over the world!

Similar Messages

Modbus Communication with Cube400

Hi
I have problem to communicate with Cube400. It is using modbus protocol and communication is going through rs485. I must connect it to cRIO 9022 serial port so I used converter IC-485SI (converter manual on page: http://www.esis.com.au/Converters/ic485si.pdf ) to change communication from rs485 to rs232.
I tried to used Modbus I/O Server. When I have one variable binded to modbus register I have proper reading. When I add second variable then I lose readings from first one. This solution is in VI called ModbusIO_rs485.
After this I tried to communicate with Cube400 by using VISA blocks. I tried to send specific modbus message. On the begging I get proper response several times but right now I am getting timeout error. This program is in VI called VISA_MBP_ForcePush.
I am attaching project with this VIs
What is wrong here ?
Best Regards
Pawel Dudzik
Attachments:
LABVIEW.zip ‏28 KB

In your program you read 16 bytes immediately after the write.
You should add some time after the write and you should see how many bytes there are available and read that number of bytes.
Look at the COM example shipped with LabVIEW.
And you use the WRONG CRC it should be 0x5679.
Try communication with the loopback command. Sending 0408 0000 8844 866D (Hex data) should return the same data
Kees

Modbus communication with a load cell

Hello..!
I'm a new user of LV and I try to communicate with a load cell by RS232 modbus.
After installed NI Modbus Library I created a master VI with labview 8.6 using these library, and I can obtain a communication with load cell , these value are added into 1 register U32Bit, and it's okay, if I press a load cell I can see the values go on.( from 0 to 65535) . Now I want to show on front panel the value in KG , as decimal point,, for a right interpretation of value for my customer, so I added a block array to unbundle than I convert a value with I32Bit ( -32768 to 32768 ) with an indicator, but I can't see any values..
I suppose I doing something of wrong ( conversion ), I read some KB, but I can't see a suitable solution..
Can someone give me a link or information to show me an example to convert this value..?
Thanks in advance for any helps..
Configuration of MAster VI:
Read holding register
Starting address 2012 ( query for obtain net value from the load cell)
quantity 1
Slave address: 1
RTU
9600
Com 3
parity none
Solved!
Go to Solution.

Hello Ravens,
I tried to use your good advices and finally I can communicate correctly with my trasducers showing on front panel the right value ( Kg). Has been a problem of conversion from output of register ( U16Bit as 0-65535 ) to I16bit ( -32765 to 32765).
Thanks very much for your help, and I hope to chat again for new challenge...
Have a nice WE
Julio
Attachments:
Comunicazione Modbus load cell.jpg ‏46 KB

Modbus communication with an automation direct GS2 AC Drive

Has anyone written any VI's to communicate with an automation direct GS2-41P0 AC Drive using modbus? I need to ask the unit a few questions while it is running and possibly start and stop it. I have started searching around and found the NIModbus VI's. I just have not figured out how to modify them to suit my needs yet (I just started playing with this today). So far it looks like Modbus might make my head explode, but I am hoping it is easier than it looks at first.
Bryan

Hi Bryan,
I've never tried using modbus to communicate with that particular device, but if you have any specific questions I'll do my best to answer them.
Also, you may be interested to know that the AutomationDirect GS2 Drive is supported by our NI-OPC Server, which may be a more attractive alternative to modbus. I highly recommend you take a look at the LabVIEW Datalogging and Supervisory Control (DSC) module (wihch includes NI-OPC Server) to see if it is something your application would benefit from.
Supported Device & Driver Plug-in List for NI-OPC Server
Connect to Any PLC
LabVIEW Datalogging and Supervisory Control
Eric V
National Instruments
Applications Engineer
Certified LabVIEW Associate Developer
"I'm a Ramblin' Wreck from Georgia Tech and a helluva (NI Applications) Engineer!"

NI OPC server communication with B&R plc

hi,
I have a NI OPC server in my lab . I want to send the data from B&R plc to the OPC server. I have tried to search for a solution but could not find any.
Kindly help me in establisihng a communication between the B&R plc and the OPC server.
Regards

Did you try installing the B&R PLC OPC server on a computer and then see if the NI OPC server can connect to it? It might not be the most elegant soloution, but it might work.
We were having problems with some siemens wincc software that would not connect to the Think&Do OPC server. So I had to bring the Think&Do OPC tags into LabVIEW and then have LabVIEW broadcast the data so the Semens OPC software could see it. I did not like doing it, but it worked.
Other than that, maybe someone else will have more to offer.

485 modbus communication with Watlow PM trouble

I have a Watlow PM that I can see over MAX now and using the EZ zone code can get manufacture info from. I also am using (for the first time) the add-on Modbus over serial tool from Saphire to try to write or read anything from it and I always get a "time out" error from the slave. I tried to do a simple VISA read as I found on some posts and I get the same time out error. It seems if I try anything from Labview I get this error. I even tried writing Hex to the thing with the same results. Can someone throw me a bone?
Solved!
Go to Solution.

There are a couple of free libraries.
http://sine.ni.com/nips/cds/view/p/lang/en/nid/201711
https://decibel.ni.com/content/docs/DOC-30140

Communication with modbus devices

Hello All,
My name Peter, I am currently exploring what LabVIEW has for instrument communication. I have explored a little on NI-Visa and used it for instrument communication through USB and Ethernet. My next task just now is to see how I can communicate with Modbus devices. I have done some background reading on modbus communication protocol and now have some level of understanding of what it is about. I hope to understand more as I continue to read more materials.
I came across an NI-Tutorial titled Connect LabVIEW to any PLC with Modbus. It is about communicating with a networked PLC using modbus. I followed all the steps described for creating Modbus master I/O Server, Binding shared variables to Modbus Address through the I/O Server and writing to Modbus Addresses in LabVIEW. On running my VI to deploy the shared variable, the following error occured.
Can anyone please guide me on what to do because I do not know exactly what is going ON. I engaged in this excercise with the hope of getting to understand more about Modbus communication and then see how I can apply thesame idea to communicate with the Modbus device available in my Laboratory. Please note that I do not yet know much about modbus communication and I am just learning about it now. I do not have any PLC connected to the network. Could that be the reason for the error? If anyone has got any other relevant document to help me get started with modbus communication I will be happy to have them posted here.
Thanks very much for taking time to read through my post message. Hope to hear a quick response from you.
Regards
Peter

Hi SmithD,
I would like to say thank you very much for making out time to respond to my queries. I have done as directed but still not getting result. Following the wire mode port setting configuration, I stopped the process and then selected the RS485/wire4 as the wire mode. On running the VI, an error pops up with the information that the Visa resource is Valid but the port cannot be accessed. I noticed that If I undeploy the shared bound variable the error does not pop up anymore. I concluded that maybe I was not supposed to have added the VISA configure Serial port in the first place.
Kindly tell me what to do.
My task is to read the holding register from a Modbus device. I have the register map with me, and know the TCP and RTU settings for this device. After the attempts I have made so far I was forced to believe that perhaps the device was not responding. I then resolved to using the QModbusMaster which was previously used to read the holding register. For reasons I don’t not know, It worked well with the TCP communication and returned an error that read " slave threw exception > unknown error". With that, I am now sure that the device is functioning properly, at least with the TCP.
Having obtained result from the TCP using QModbusMaster application, I want to simply do the same using LabVIEW.
Some few questions for which I would want to ask for clarification are:
1.) When using the Modbus Library, do I need to create both master and slave instance to be able to read the holding register? My attempt was to create a Master instance with the RTU parameters. The starting address and number of registers were specified at the input terminals of the Read Holding Register VI. This VI immediately followed the Create Master Instance VI. I was expecting that that would read the information contained in the specified registers and output it at the register value terminal. One challenge with this attempt was that with RTU it didn't work. I tried selecting TCP as the VISA resource. But the device was not showing on the list. I went to MAX to create a new VISA TCP/IP resource under the network devices but MAX could not detect the presence of the device. I am now thinking maybe the device is not supported by NI-VISA and so it will not be possible to use the Modbus Library with it.
2.) If the device is actually not compatible with NI-VISA, can DSC I/O server be used to read the information on the holding register?
3.) Do I need an intermediate device between a Modbus device and the PC to be able to read its holding register?
Please if anybody has got a good suggestion as to what to do to get my task achieved, kindly leave me a post.
Thanks
PETER

Modbus Communications address offset

Is there an option available in the Modicon Object to enable an address shift during communication with Modicon Devices. When communicating with a Modicon Quantum PLC 400010 will return the value from the device in reg 400010 but when communication with a Modicon M340, Premium and others 400010 will return the value in 400009.

Nothing a little data member export and import cant fix...
On the standard Koyo (automationdirect) PLCs we have to convert from Octal to decimal, then add 1.
For example:
PLC: V1200
Decimal: 640
MODBUS: 40641
Forshock - Consult.Develop.Solve.

Has anyone tried to use LabVIEW as a modbus slave with a PLC master?

Hello. I use modbus extensively with PLCs as slaves. I am finding that it might be benificial to make the PLCs be the master in my next application. I have tried this with the MB Ethernet Example Slave.vi without any luck. Can anyone help?
I am running LabVIEW 8.6 on Windows XP with AutomationDirect PLCs using ethernet communication.
Thank you in advance for your help.
Ron Deavers, CLD

Hi
There are two options to connect to a Modbus device. Either the Modbus IO Servers (found in the NI LabVIEW Datalogging and Supervisory Control Module) or the free Modbus Library.
FLAsh
National Instruments
Applications Engineer

Modbus TCP to Modicon PLC using Modus library

Hello. First, FWIW, I have zero experience using a network or Modbus. I need to communicate to a Modicon Quantum PLC using the modbus library. Looking at the provided examples of TCP in the library it seems straight forward but I am evidently missing something. It seems regardless of the address I send to the PLC I receive no response. I am using the "MB Ethernet example Master.vi". Since the PLC is currently in operation I deleted the "coils to write" and "registers to write" events from the example since I didn't want to accidently cause any operational problems. That leaves me with the simple 'time out' event executing every 100 ms reading coils and registers. I have the network address of the PLC and using a cross over cable directly from the computer, I can see the tcp receive and send lights flashing on the plc's communiction module as I attempt to read coils or registers. But, I get no visible response written to the slave discrete inputs or the slave input registers arrays on the example front panel. I added a loop to write addresses starting at 0 and let it run up to 12000 with no response. The only documentation that has been provided to me about the PLC is a list of the PLC variable memory addresses. All the addresses are either a 6 digit number starting with 4 (400063) or a 3 digit number such as 299. If I try to send a 6 digit address the example returns an error and sending any other number ,at least up to 12000, gets no visible indication of response in the example. I would appreciate someone cluing me in to what I'm not doing or what I'm doing wrong. Hope the question makes sense. Thanks.

I'm a bit confused as to what you are trying to do. From your post it appears as if you are using the MB Ethernet Example Master VI, but are you also using the MB Ethernet Example Slave VI as well? If you are running the Slave VI and update the Discrete Inputs or Input Registers, the Master VI should pick up on that if they are set up correctly. Also, you modified the Master VI, did you also modify the Slave VI?
Stephanie O.
DIAdem Product Manager
National Instruments

Communication Problem in Mitsubushi PLC A2SH with OPC 4.5.1

While communicating with Mitsubushi PLC A2SH thru OPC 4.5.1 , it displays time out error , the settings of the Com port of the system is Baud = 9600, Parity = odd
Data bits = 8 Stop bits = 2, Flow Control = None . The same setting is done in the OPC & Mistubushi PLC Comm protocol. Iam using Labview DSC to communicate with PLC with OPC 4.5.1. How do i solve this Comm Problem in what steps.

You might increase the 'Recieve timeout' from 250ms to some higher values on the object (driver) and you might increase in Options >> Serial Ports... >> Receive Gap from 20 to a bigger value like 50.
Hope it helps.
Roland
PS: I've not tried it with this particular PLC, though.

How can I configure labview for communication with Modbus I/O?

i read a article about configureing Labview for communication with modbus I/O in NI developer zone, but it was written for Labview 6, how can I configure it with labview 7. it seems there are some difference. Thanks!

In both LabVIEW 6 and 7, you connect to modbus using Lookout Protocol Drivers (LPD) and then communicate to LPD using the tag engine of LabVIEW DSC or through DataSocket.

Direct communication with SIEMENS PLC

I am trying to establish a direct connection with a SIEMENS S7 PLC. I donot want to use any card or profibus etc. I want to do it through the Serial Port.
I have used the IA server kit when communicating with SIEMENS S5 for which I used AS511 protocol. I would like to know if there is any such protocol for S7.
Please Help!!

Hi.
I'll try explain it.
All Simatic S5 PLc's processors (CPU90 ,CPU100) have got serial (current loop converted to RS232) physical inteface as standard.
You can program PLC's or communicate with its by AS511 protocol.
S7 Simatics processors (CPU 3xx, CPU4xx) haven't got RS232 interface as standard. RS 232 interface occurs in forms of interface module connected to the rail (slot) and doesn't serve any protocol (simple chracters exchange).
You can program PLC, observe/modify I/O, variables, etc. only by standard RS485 interface using protocols MPI or PROFIBUS (PPI/MPI for Simatic S7-2xx CPU's).
You can try exchange data between Labview and S7 PLC by serial in characters form, but it is very difficult and inconvenient (you have to w
rite own driver for Labview and program for S7).
Another solutions:
1.PROFIBUS card for PC with drivers for Labview (I don't know if they exist)
2.connection thru OPC server (PLC->PC by PROFIBUS card->OPC server->Labview by Datasocket)
I think second solution is more comfortable.
See also:
Connecting LabVIEW to an OPC Server through a DataSocket Connection
Regards.
Romek.

How does labview opc communication with plc affect timing for the actual plc application

Hi Everyone,
I have a doubt and thus want to start a discussion regarding communication with PLC's from NI OPC server.
Let's imagine you have a production machine like a caping machine for a bottle production line, let's say the PLC on this machine is a Siemens S7300 which according to NI is compatible with NI OPC server.
The PLC would have already been programmed by the company who sells the machine to control it correctly.
The question is, if you'd like to add an interface, and all the capabilities that LabVIEW offers to this machine by controlling/monitoring its PLC, returning its alarms etc...
In that configuration is there a possibility that the LabVIEW application you would devellop affects the PLC's Behaviour and thus the machine functionality or yield and thus would have a negative impact?
Thanks a lot for your answers.
Best Regards,

Hi Olivioloyer Good Morning:
The issue here is that if you want to control, display and log data and funcionality from that PLC through LabVIEW you will have to change the program on the PLC to work correctly with your Interface and Alarming program that you will create in LabVIEW. If you develop a well designed architecture and an efficient code there will be no negative impact on yout PLC, on the contrary you will expand the funcionality and capability of your application.
Note: You will need to change your PLC program to achieve correct functionality with what your LabVIEW code will do.(Send and receive control commands). If you just want to monitor your PLCs behaviour, your code will be much more simple and maybe no change will be required on the PLCs program.
Juan Arguello
National Instruments México y Latinoamérica
Applications Engineer

Automationdirect P3000 Modbus Communication Lookout 6.5 for +/- 10V Output Module

Here is an iquiry I sent to Automationdirect tech support last week.
I have not had a response from them yet so I thought I would throw it up here.
Hello,
I am starting a new project with the P3K and I am using Lookout 6.5.
This is my fourth installation with this combination and I have learned a bit more about the Modbus communication each time.
I use the Modbus serial object in Lookout to communicate via RS-232.
With my first project, I learned to set the "Modbus Server Settings" in the P3000 software to map to a single 16 bit Modbus register to get the communications working with Lookout and making sense with the analog registers.
For a 10V input I would linear scale in the PAC 0 to 65535 = 0 to 10000 then in Lookout I simply divide by 1000 to get the decimal in the right place.
On the most recent project, I discovered I could map/scale my analog inputs to 32 bit foats, select the "map to two consecutive integers" in the P300 software properties and then in Lookout, I could read the register properly with an "F"
like "modbus1.F400001".
Now I have a P3-16DA-2, ±10V output module.
I can't get the float to work and it crashes the communication repetitively.
It will communicate properly if I stick to 16 bit Modbus register for the "Analog Output, Integer, 32 bit" on the Modbus server settings.
However, I have the register swap issue reminiscent of the DL205 bi-polar input. It outputs 0 to 10V from 0 to 32767 and -10 to 0 from 32768 to 65535.
I remember having to add logic in the DL260 PLC and then in Lookout I would use the numerical IF;
"(nif(DL3.C102,DL3.V2102*-1,DL3.V2102))*-1"
What a pain that was.
Is there an easy solution?
Thanks in advance.
John B

Bipolar setups are a pain, it seems your if() is similar to what we did as well. Added a rung and set a coil...
Only have a few and have not used the P3000 myself,
Forshock - Consult.Develop.Solve.

Modbus communication with Modicon premium PLC

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