Jump to content

Search the Community

Showing results for tags 'Modbus'.

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • Our Community
    • Come on in!
  • News and Announcements
    • UniLogic 2021-- UniCloud IIoT Cloud Platform, EtherCAT & more!
    • VisiLogic:9.8.64 - Link to mobile app, Ladder: 2x the Space!
    • New!!! ***** U90 Ladder*****
  • UniStream HMI + PLC Programmable Controllers & UniLogic Software
    • UniStream: Hardware
    • UniLogic Software
    • UniLogic UDFBs
    • Industry 4.0, IioT, MQTT, OPC UA
  • Vision, Samba, Jazz and M90 PLC + HMIs & Software
    • Vision & Samba PLC + HMI Controllers & VisiLogic Software
    • Jazz, M91 PLCs and U90Ladder
  • Motion! Servo Drives, Motors, Actuators, & VFDs by Unitronics
    • Motion: Unitronics Servo Drives, Motors, Actuators, VFDs--by Unitronics
  • Software Utilities
    • SD Card Suite
    • Remote Operator
    • Remote Access
    • DataXport and DataXls
    • UniDownloader
    • UniOPC
    • UniDDE
  • Utilities for .net and Visual Studio
    • Unitronics PCOM Protocol
    • COM Object ActiveX .dll
    • .NET driver
  • Project Design
    • ...I have a project...what hardware do I need?
  • User Application Stories
    • Just finished a great project?
  • Tips and Tricks
    • Best Programming Practices
    • Tips and Tricks
  • Job Board
    • Projects seeking Programmers
    • Programmers seeking Projects
  • General Discussion
    • We're Listening...
    • The Lounge
  • News and Announcements Copy


  • Unitronics' Blog: PLCs, HMIs and more
  • Saragani's Blog
  • Simon's Blog
  • Ash Neilson's Blog
  • Joe Tauser's Blog
  • Unitronics en Español
  • Powered by AMPS
  • Alldrives UK's Blog
  • Unitronics, Howman Style
  • PLCNewbie's Blog
  • Telestar Automation Blog
  • Webinars Collection
  • Tim's Corner
  • Blog
  • TELESTAR (Italian)
  • i4 Automation
  • i4 Automation (UK)
  • Unistream UDFB's


  • From Headquarters: Sample Applications
    • From Headquarters: VisiLogic
    • From Unitronics: U90 Ladder applications
  • User-submitted Applications
    • From Users: VisiLogic applications
    • From Users: U90 Applications


  • Articles
    • Forum Integration
    • Frontpage
  • Pages
  • Miscellaneous
    • Databases
    • Templates
    • Media

Find results in...

Find results that contain...

Date Created

  • Start


Last Updated

  • Start


Filter by number of...


  • Start





Website URL







  1. Hello, I'm trying to poll some values from Laumas weight transmitter - and I'm kind of stuck. I've tried to read some addresses according to the Laumas manual, but the power-up value in the receiving variable is never overwritten. I get modbus status as -11, which I don't know what means. THe setup: It should be reading all the time if set up as periodic and the active bit is set ? The values when running: Anybody with any hints for me? Thanks, Bjarni
  2. Dear all, We communicate 10 nodes through rs485 communication in v700 port 1..the problem is if my one divice is failture means other 9 nodes getting delayed..kindly provide solution RegArds Mohamed
  3. Hello, I'm just starting my first project with UniStream/UniLogic and I have the PLC hooked to a PC via Modbus, PLC as Slave. I haven't found a way to sync the clock in PLC with the PC clock. Is there a way to set the PLC clock via the Modbus ? Thanks, Bjarni
  4. Hi I'm new to PLC operations, and I was hoping I could get some help getting started with MODBUS communications. I have a PLC/HMI running UniLogic and Festo CMMO which I am trying to run over MODBUS TCP. I have added the remote slave, and downloaded the program onto the PLC. However, I haven't been able to get any proof of the connection. I have added registers (3 and 17) based on reads to tags (INT16), but they all display as 0. I have also tried displaying the value of slave.sessions, but it also shows 0 which leads me to believe it has not even tried to start the connection yet.
  5. Dear colleagues. I hope you are doing fine. I have 5 power meters in a RS485 bus communicating through Modbus RTU with one Unistream which is acting as master. 3 of them are from the same brand and model. They are all ok, connecting and communicating. The registers are 32 bit length (treated as INT32 in the Unilogic). So far everything is good. For the other 2, from different manufacturer, It seems I am receiving the data in a strange way because the data is not coherent. It seems I am receiving the words or bytes inverted. if I use a external Modbus client in my laptot, I
  6. Hi Would like to get some assistance on the following, im using a US5/7-B5-TR22 with a UAC-CX-01RS4 for rs485 comms Im talking to a single UV lamp ballast, I carnt seem to get any comms working, the ballast has LED indicators for when comms in working/ fault and also transmit and receive LED,s, I have got these on once then haven't managed to get them to come back, Im thinking its a software issue as I used some software off the internet "simply Modbus master" and could send commands and receive reply's, I have had this working before with a similar ballast talking re485
  7. Hi, I'm using a Samba 3.5 with ethernet card to send data to scada system. With test purposes I'm trying to send a discrete input MB 0 in response to the read digital input command (0x02) with the following instruction: But in the test software (Simply Modbus TCP Client) I can't see the value of MB0. Trying to find the answer, I tested sending the MI10 value in response to read holding registers command, but It doesn't work neither. I'm using the modbus TCP initial setup from the examples and the webinars, and I can see the connection in the Samba, but I can't send th
  8. Hi all, I use USC-P-B10 with USP-070-B08 (modular HMI/PLC) as a master via Modbus Ethernet. Could anyone recommend me how to catch an exception in UniLogic 1.26.90 if slave is not responsive (powered down, loose cable...). Thanks
  9. Hi all, Would you mind to show me some example how to treat INT16 as a power in W and its scale factor INT16 received via Modbus, please? Should I firstly convert them into Real, then multiply them? Thanks
  10. Does anybody know if Vision controllers (ie V130) support Modbus TCP or do they support the Modbus RTU over TCP implementation. The difference is that the first follows the original Modbus TCP frames (ie no CRC) while the latter encapsulates the serial RTU framing sent over TCP media. Which one is supported by Vision and the other Unitronics controllers?
  11. Hi, today in our company we received an ultra filtration system that comes with a V1040 on it. We've never had worked with an unitronics system before and we are trying to communicate the plc via modbus rtu over rs485 to work with our network. We configured the com port of the plc to work with rs485 as it was factory configured to work with rs232 but we can't reach it on our system, it's just showing of offline status. In the ladders we had a special subroutine for modbus, including all the registers and status of the system, we are reaching these points but it doesn't work. I'll attach
  12. 1) When editing IO Inputs or Outputs Alias Names directly (from the table view, without going into window for editing single tag) - cold not put a space symbol between words while writing (later when the whole "Input5AbracadabraOpenSesame" is written, you can, of course go back and put spaces in between words finally getting to the "Input 5 Abracadabra Open Sesame"). Problem is not observed while editing in single tag editor window. This is new mis-behavior, which was not observed some versions earlier. 2) In Data Table view - String literals are center-aligned without any obvious reaso
  13. I need to read multiple Modbus registers from a non Unitronics controller. These registers are not consecutive registers. What is the best way to do this? Multiple Read Holding Registers (3) one after another? Rung examples of your ideas would be most helpful and appreciated. Thanks!!!
  14. In helping a customer integrate a UniStream into a SCADA system I have come across a curious gap in the available information. I can't see any declaration of the function codes that the external Modbus master must use to communicate with the UniStream as a slave. The Unitronics example and tutorials use a UniStream as the master as well as the slave, which doesn't highlight this issue. I have looked within UniLogic, tried exporting the Modbus registers as excel, looked at the UniLogic help file, watched the Unitronics YouTube video and searched the forum. None of these sources gave t
  15. Hello: I am having trouble to communicate my V1040 with an existing Schneider Electric M221 with the serial port. It was supposed to be easy, but I don't receive any answer from the M221. V1040 has 2 ports, and I am using port 2. The port has been set up for RS485 with termination with the DIP switches. MODBUS protocol is: Baud rate: 19200 Parity: NONE Stop Bit: 1 wires has been checked and also pinout. My first concern is about the pinout. Schneider requires 3 wires on RS485. It uses D1, D0 and ground, while V1040 only uses A+ (D1) and B- (D0), but no ground as r
  16. Hi! So, I am writing ASP Core 2 project and one of the components is communicating with Unitronics V130 unit (as a Modbus Slave). Since provided .NET Driver library is not portable to ASP Core I need to implement this communication with Modbus. I have limited experience with Modbus protocols but I have used some basic functions in the past – mostly reading Registers and Coils. Just to sample some data. I used python library modbus_tk for this purpose. Using Modbus gives me options for adding more optional hardware down the line. After reviewing some libraries supporting Core I selected
  17. Hi All, I'm using the UniStream as a slave connected by Modbus TCP. Is there a way to know/check the forwarded data, by the Master, byte to byte? thanks
  18. Good morning everyone! We are about to begin work on a Modbus deployment that will need far more than just the 255 addresses available on the built in CPU master. I know we can add up to three of the UAC-02RSC UniComm modules for three more masters. Unfortunately, the masters on the 02RSC have a limit of 512 operations each, so we’re going to need all three modules and then some. I’m interested in using the serial port on the top of those modules as well. Unilogic and the built-in help file shows that we can turn them into Modbus masters, but we’re not having any success getting i
  19. I want to buy and use an Unistream PLC. I am trying to read the specs for an {Unistream 7" HMI PANEL (USP-070-B10) + Unistream CPU FOR PANEL (USC-P-B10)}, but I can not find that this this system supports Modbus TCP/IP and Modbus RTU.? Can anyone answer this question and tell me which datasheet shows this information. Thanks!
  20. Hello. I am forced to ask you for help, as I spent a lot of time trying to solve this problem on my own. I just can’t connect PLC V350 Vision with OPS server UNIOPS + SCADA. By TSP IP I managed with great difficulty to establish a connection with this controller (nowhere did I find an intelligible, complete description of the connection), but now this is not about it. I tried various options, but nothing works. I enclose screenshots for clarity, can someone tell me what else I need to do in order for the VISION PLC 350 to see the OPS server. I would be grateful for any help. Thanks. . Th
  21. I have a problem, when a slave is disconnected (without opening the trunk network) all other slaves lose the communication of the master. Does anyone have the method or solution of how to do it?
  22. HI, I'm trying to communicate with another device via my V350. I'm using Modbus IP and I can successfully connect and read the 16-bit registers. However when I try to read the 32-bit registers I get either some very small numbers, below was my best guess, but as you can see I get a very small number. (should be 32856.876) I would also like to be able to read the 64-bit registers if possible Thanks All the best, Palsson
  23. Hi everyone I'm fairly new at unitronics and I'm doing a project that calls for the use of two EX-RC1 connected by modbus. I've been going through the webinars ( and ) and I'm still in the dark as to how I set upthe EX-RC's for my I/O expansions. In my first RC I have the following I/O's : #0: D16A3-RO16 #1:AO6X 2#: AO6X #3: AO6X #4:AI8 #5AI8 In the second RC I have four IO-PT400 modules I've tried following the second youtube clip, using the EX-RC1 example file where I've added my I/O's, but I get an error when I try to export the Hardware config: 'Export failed
  24. Hello, I am developping an application that uses Bronkhorst mass flow controllers with modbus communication. Some years later, I used a vision V570 with success. This time, I am using an Unistream and reading floats with modbus doesn't work properly : the 2 registers are inverted so the value is wrong. I tried to revert the register by using buffers and it works perfectly for read values but values to be written are rounded so I can't send setpoint to my controllers. Does anyone have an explanation ? Below is a snapshot of the conversion code :
  25. Hello, I'm currently trying to read an encoder value from a drive via ModBus. The encoder value is split into higher 16 bit and lower 16 bit, hence I have to read two registers. Is there an easy way to combine the two values to get the single 32 bit value I'm after? TIA Jamie
  • Create New...