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Found 9 results

  1. 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 some screenshots of the COM and modbus configuration and the modbus registers that i'm trying to read and i'll appreciate any help if i'm doing something wrong. Also, if i modify the program i need to upload it all or there is an option to upload only the com configuration without stop the plc? Due to the critic status of the process i only have a few minutes to stop the plc so i'll appreciate any shortcut to work faster on the system. As i said we've never worked with this plc before so we don't know the kind of responses of the system.
  2. Dear all, I'm programming an application on a SM43-J-R20 PLC+HMI. I've added a V100-17-RS4X card, in order to use RS485. I've succesfully implemented Modbus RTU communication with a Frequency Drive. The thing is, I need to communicate with 11 of them. The ladder logic so far uses the Modbus function blocks, as can be seen on the Modbus webinars on Unitronics page. That is, I SET a variable (ex:MB0) , which is used for enabling the "function 06 Modbus" block (preset holding register). At the output of the block, I RESET that same variable, ensuring the block gets executed. At the same time I reset MB0, I SET a new variable (MB1), which in turn is used for enabling the second Modbus block. This creates a sort of "continuous broadcast" to the drivers (which, If they don't receive a command in a certain time, trigger a failure). When the last block gets executed, the sequence restarts, The question is, when I try to send a Stop command to one driver (for example), it takes an awful amount of time to execute the order (30 seconds or so). I believe I may have a conflict between some of this blocks being executed at the same time. Is there a tutorial or an example where I can see how to succesfully implement Modbus communication with several slaves at the same time? Thanks for the support. Kind regards, Martin
  3. Hello, For a project im working on I need to motitor serval energy sources and control multiple relays. I would like to use the Samba 4.3" PLC for giving a nice interface to the system. The problem is that I have over 30 outpust I need to control. I've found a modbus RTU (RS485) energy meter who measures the voltage and current. Also found a modbus RTU (RS485) digital output module with 16 outputs. Is it possible to use the Samba 4.3" PLC with V100-17-RS4 module to communicate over modbus with the IO modules and energy meters? Best Regards, Jelmer
  4. Hi, I'm running an Arduino-based home automation system. My custom-made Arduino clones are communicating over a RS485 network (configured as 8N1) using Modbus RTU protocol. Thing is that I want to have a reliable, industrial-grade PLC in the network, in order to monitor my Arduino-based sub modules. Basically I need a cost efficient Unitronics PLC capable of connecting to RS485 network, The ladder program is expected to be non memory hungry, also I'm fine with good old 2 line display. The PLC must be able to connect to the RS485 network without the use of any extension modules/communication modules /.etc (native COM port on a screw terminal). Any suggestions? Thank You.
  5. Hey guys, I'm often needing to use advanced modbus features because ill need to have dynamically adddressed slave ID's, or changing registers etc, etc and i cant use the built in configuration to do so. Also - the Advanced modbus still require a good bit of logic to be built in order to achieve a good Tx and Rx. I built this UDFB to be used as a single operation which accepts 4 Function In parameters, and one Function out. Example Ladder Note how the function is called, Param 'D' must be reset immediately after the function call: Ladder Image Input A is a struct with 4 members (Note that only one Arr at a time will be filled with the result data, based on your input to parameter 'B') resultBits[0-50] resultInts[0-50] resultUInts[0-50] resultRaw[0-99] The results of your query are stored here, depending on what value you use for input 'B' 1 = result store in resultsBits 2= result stored in resultInts 3= result stored in resultUints 4= result stored in raw buffer( for parsing floating point values etc, etc) Input 'C' is your input parameters for the MB request - Don't worry about the Modbus request, and request descriptor - these are handled inside the function Input 'C' is a struct with the following members slaveId functionCode = Standard codes...holding register = 3, etc startReg = starting register in slave length = how many registers(Keep in mind length of buffers etc, you can always change this) Retries = how many times to retry read request Timeout = how long to wait for response(5000 = 5 seconds -- 3 retries at 5sec each would be 15 secs for a failed attempt) Input 'D' is the Enable bit for the function to run - make sure to reset this immediately after the function call.(See image above) Output 'A' is a number with the following values 1 = read successful 5 = timeout (timeout * retries) 255 = ladder Error Let me know if i made a glaring mistake, or if you have any improvements! I'm sure i didnt do this as effeciently as possible - but, it does work for my purposes. I may add some more error checking and things later. Let me know what you think! Thanks, Matt MBR.ulle
  6. 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?
  7. Hi, I'm writing an application involving 1 master and 9 slave controllers - all Unitronics. The master PLC is a V1210. One of the slaves is also a V1210. The remaining 8 slaves are V130s. All i'm trying to do is sequentially read 1 coil from each of the slave PLCs. I know that this should be ridiculously easy... ...However, I'm finding that the "Function in Progress" bit gets stuck on after the master only attempting to read from 2 of the slaves. I've tried using timers of 100ms - probably excessive - after each Modbus Read Coils function block. Also, just to mention, I don't have all 9 slave controllers with me for testing - I've got 2. Is Modbus good at handling when it can't get thru to a particular node and just moving on to attempt the next one? Any help much appreciated, James
  8. Hi everybody, Greetings to all, another newbie here... Having some issues on getting Modbus RTU messages to work on JAZZ PLC. My setup: 1) JZ20-R16 PLC with MJ20-PRG adapter (?) plugged in it. I'm using MJ20-CB200 cable (RJ11 plugs on both ends) and MJ10--22-CS10 adaptor (DB9 female connector). Using this gear I can query the PLC with modbus RTU messages over RS232 serial line. Serial line settings I use: 9600bps, 8(data bits), none(parity), 1(stop bits) 2) Gemalto modem (BGS5T) as a modbus master. It has DB9 female connector on it as well. 3) Serial to USB converter cable for serial communication verification. A bit of context: while using serial-to-usb cable I can't query PLC all the time. That means, *sometimes* I can query it successfully, but after disconnecting and messing around a bit I cannot query PLC any more. Unplugging USB-to-serial and reconnecting helps, so I assume it's kinda converter drivers/whatever issues so not a big deal here, just a note. So using this cable I can verify, that PLC *can* (though not always I would expect) respond to Modbus RTU messages properly using defined settings above. I have couple of Modbus master simulation programs and strangely enough only one of them can query the PLC successfully. Real problem: I have written peace of software for BGS5T to act as a modbus tcp/ip to modbus rtu gateway. I can verify that this gateway works by three methods: 1) run modbus slave simulator on a PC, connect gateway over serial line to PC (same usb-to-serial cable used here) and query PC slave simulator over that modem acting as a gateway. Everything's just fine. 2) I can connect to the terminal program on a PC and verify that sent message to serial line is valid modbus RTU message: 0x01 0x03 0x00 0x02 0x00 0x01 0x25 0xCA : (from left to right hexadecimal values) 1) device ID (1 byte) 2) function code (1 byte) 3) start address (2 bytes) 4) register count to read (2 bytes) 5) CRC (MSB) 6) CRC (LSB) 3) I have made "sniffing" rs232 cable and I can listen on messages being set to PLC or being received from PLC (depends on wire I'm hooking to). I can verify that exactly the message defined above is sent to PLC using serial settings mentioned above. PLC does not respond with anything. Absolute silence.... I used 3 wire connections (Tx, Rx, GND), used null-modem configuration for both modem and PLC, nothing helps. JAZZ PLC is silent for those messages. What could be wrong here? Voltage levels does not match..? handshaking is mandatory on JAZZ PLCs..? I'm completelly out of ideas to try out, cannot sleep normally over a week now... I don't know much details about serial line physical implementation, so feel unsure in this topic. Please help. Regards from LTU
  9. Hello everyone, I have two devices on the same RS485 line: one is a standart MODBUS RTU device, the second uses its own protocol in ASCII code. COM2 is configured to 9600 n 8 1 and I use positive pulses with 1 sec timing to activate Protocol Configuration FB and MODBUS Configuraton FB. The cycle starts with the ASCII device, then after getting the reponse I switch to MODBUS and get the required data, but when I switch back to the first ASCII device, even though OPLC sends the data, I receive no response. If I try to send the same data again, I get the response and proceed to MODBUS request and so on and so on, but the fist ASCII request after MODBUS gets no response, while the second request straightaway gets the data. Both the device work perfectly well independently, and I have tested the above described cycle both automatically and manually, so I am pretty sure it is not a timing issue. Would anyone kindly advise me on the situation? Is it an OPLC issue (something to do with buffer clearing in Modbus mode) or maybe it is a Modbus slave issue (ie commnication ports dont close or else)? Unfortunately I am not that good with Modbus yet, and googling the problem didnt help.
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