Alison Posted March 3 Report Share Posted March 3 Hi all. I am brand new to all this, so please don't savage me too badly. I have a Vision 350 here, and I want to get it talking to two different Modbus machines - a heat pump and a variable speed motor drive. Initially I just want to poll the units from my Vision to find out stuff like speed of drive, or heat pump temp. I have modbus "maps" for both units so that helps! Eventually I'd like to use the Vision to control our entire pool set-up - I work for a swimming pool equipment wholesaler. This is really just me trying to teach myself something new, but getting more control over the VSD would be great (eventually). I've started off following the videos on Modbus and on PLC basics but I'm struggling with some things, just because I'm no programmer and this is all new to me. Could anyone please suggest some good starting points - tutorials, videos, further reading - that might help? For example I don't know why, as the first step in the Modbus vids, a system bit is used in the first net. I must have missed what this is/does somewhere - I feel like I have missed a set of videos inbetween the "What is a PLC/HMI" and "How to work Modbus" ones!! Thus far my understanding is that you make a pretty interface screen, tie the things you're doing on that screen to "nets" (which are basically steps in a program) and the Vision will follow the structure of the ladder from top to bottom. I *think* that the Vision (as Master) polls the Slave units, gets data from them from whichever modbus address I point it at, loads that data into its own memory and uses the data as variables that I've defined, then keeps on repeating that process. Am I anywhere near right, here? Thanks Alison Quote Link to comment Share on other sites More sharing options...
MVP 2021 Joe Tauser Posted March 3 MVP 2021 Report Share Posted March 3 Your initial investigation is a good start. If you haven't already, download and install Visilogic. Then under the Help menu choose "Examples" and start digging through the folders to see what's available. Eventually you'll find Modbus examples under the Project-> Communications folder. Do your heat pump and VFD use serial or Ethernet communications? Joe T. Quote Link to comment Share on other sites More sharing options...
MVP 2021 Flex727 Posted March 3 MVP 2021 Report Share Posted March 3 Unitronics presents training webinars regularly which get posted to their YouTube channel. Browse those videos to get basic training on VisiLogic. Here's a link to one to get you started: I'll also suggest that you browse the Help file in VisiLogic in addition to the example projects, as Joe mentioned. Quote Link to comment Share on other sites More sharing options...
MVP 2021 Flex727 Posted March 3 MVP 2021 Report Share Posted March 3 It also should be mentioned that programming all models of the Unitronics Enhanced Vision series is nearly identical. This includes your V350 and the V570 in the video I linked to, as well as the models used in the example projects. Quote Link to comment Share on other sites More sharing options...
Fernando Castro Posted March 6 Report Share Posted March 6 On 3/3/2023 at 6:53 AM, Alison said: Hi all. I am brand new to all this, so please don't savage me too badly. I have a Vision 350 here, and I want to get it talking to two different Modbus machines - a heat pump and a variable speed motor drive. Initially I just want to poll the units from my Vision to find out stuff like speed of drive, or heat pump temp. I have modbus "maps" for both units so that helps! Eventually I'd like to use the Vision to control our entire pool set-up - I work for a swimming pool equipment wholesaler. This is really just me trying to teach myself something new, but getting more control over the VSD would be great (eventually). I've started off following the videos on Modbus and on PLC basics but I'm struggling with some things, just because I'm no programmer and this is all new to me. Could anyone please suggest some good starting points - tutorials, videos, further reading - that might help? For example I don't know why, as the first step in the Modbus vids, a system bit is used in the first net. I must have missed what this is/does somewhere - I feel like I have missed a set of videos inbetween the "What is a PLC/HMI" and "How to work Modbus" ones!! Thus far my understanding is that you make a pretty interface screen, tie the things you're doing on that screen to "nets" (which are basically steps in a program) and the Vision will follow the structure of the ladder from top to bottom. I *think* that the Vision (as Master) polls the Slave units, gets data from them from whichever modbus address I point it at, loads that data into its own memory and uses the data as variables that I've defined, then keeps on repeating that process. Am I anywhere near right, here? Thanks Alison it uses SB because yo just need to run it once at the beginning, there are some notes about that on the documentation.. I would start reading, reading the documentation regarding the Modbus protocol in general. Quote Link to comment Share on other sites More sharing options...
Alison Posted March 8 Author Report Share Posted March 8 Both units use Modbus RTU over serial which is a relief, I don't want to have to learn networking too!! Quote Link to comment Share on other sites More sharing options...
Fernando Castro Posted March 8 Report Share Posted March 8 2 hours ago, Alison said: Both units use Modbus RTU over serial which is a relief, I don't want to have to learn networking too!! the protocol works pretty much the same over TCP/IP or serial the main point to understand in the protocol is that Modbus works with memory registers and that there is a table and "register codes" depending on the type of each variable. also, some devices start counting from 0 others from 1 so it depends really on the implementation of the protocol on each device, for example in the Unitronics documentation there is a "formula" on how to calculate the Modbus addressess based on the type of operand. Wich, I think is different based if its "Enhanced" version or "standard" version. having said that, that doesn't mean anything without understanding how the Modbus addresses works. Quote Link to comment Share on other sites More sharing options...
EPSAuto Posted March 9 Report Share Posted March 9 Hi all, I'm also brand new to PLCs and am trying to connect to the PLC. I have followed the videos and help page but I have no luck on connecting it. The PLC I'm trying to connect has a programme in it already but I'm getting this following error. Any ideas? Quote Link to comment Share on other sites More sharing options...
MVP 2021 Joe Tauser Posted March 9 MVP 2021 Report Share Posted March 9 PLC model number? USB, RS232, or Ethernet? Joe T. Quote Link to comment Share on other sites More sharing options...
EPSAuto Posted March 9 Report Share Posted March 9 V1040-T20B and I'm trying to connect via USB, Have checked the driver and is working good. Have selected the correct COM port. Still no luck Quote Link to comment Share on other sites More sharing options...
MVP 2021 Flex727 Posted March 9 MVP 2021 Report Share Posted March 9 Is your V1040 new, or does it already have a program in it? If there's already a program, it may have initialized COM1 as something incompatible with VisiLogic. Go into INFO Mode and check it. Also, screenshot your Connection window so we can see if that is set up properly. Quote Link to comment Share on other sites More sharing options...
Alison Posted Wednesday at 03:53 PM Author Report Share Posted Wednesday at 03:53 PM My 350 gave the same error (it had a program on already; I have *cough* liberated it from a piece of redundant equipment) and I followed the sticky topic here on bricked Vision units which did the trick. Quote Link to comment Share on other sites More sharing options...
Alison Posted Friday at 10:58 AM Author Report Share Posted Friday at 10:58 AM Okay, bear with me here. I have a Vision 350 J T38. This has a USB micro port for programming (great, that works, yay, and I am happily plugging away through the basics of ladder logic, thank you for that!) It also has an RJ11 port, and RJ45 which is labelled EXP PORT. The VFD I want to talk to has a USB port(s). I have also got a USB/RS485 adaptor cable, which has 6 wires on - red, green, brown and black, plus orange and yellow. How do I get from the USB port on the VFD, to the RJ11 port on the PLC? I have some RJ11 phone cable but that only has four wires in. I am assuming the RJ45 port on the PLC is for extra I/O units only, or am I making an error here? Quote Link to comment Share on other sites More sharing options...
MVP 2021 Flex727 Posted Friday at 01:17 PM MVP 2021 Report Share Posted Friday at 01:17 PM 2 hours ago, Alison said: How do I get from the USB port on the VFD, to the RJ11 port on the PLC? I have some RJ11 phone cable but that only has four wires in. I am assuming the RJ45 port on the PLC is for extra I/O units only, or am I making an error here? The RJ11 port on the PLC is a standard serial port. Converting from USB to serial is fairly straightforward (I think), but I'm not a wiring guy. I have seen USB-to-RJ11 cables on the market. Yes, the RJ45 port is for connecting external I/O modules. Unitronics has a lot of documentation available online. I recommend reviewing it. Here is the User Guide for the V350-JT38: https://unitronicsplc.com/Documents/Vision/PLC/UG_V130_350_430-T38.pdf Quote Link to comment Share on other sites More sharing options...
Fernando Castro Posted Friday at 04:40 PM Report Share Posted Friday at 04:40 PM 5 hours ago, Alison said: Okay, bear with me here. I have a Vision 350 J T38. This has a USB micro port for programming (great, that works, yay, and I am happily plugging away through the basics of ladder logic, thank you for that!) It also has an RJ11 port, and RJ45 which is labelled EXP PORT. The VFD I want to talk to has a USB port(s). I have also got a USB/RS485 adaptor cable, which has 6 wires on - red, green, brown and black, plus orange and yellow. How do I get from the USB port on the VFD, to the RJ11 port on the PLC? I have some RJ11 phone cable but that only has four wires in. I am assuming the RJ45 port on the PLC is for extra I/O units only, or am I making an error here? Do you have the VFD model? its odd to me that it has an USB port, I haven't seen any RS4-85 port using USB (I may be wrong), but I have seen RS485-To USB converters embedded (Like Unitronics do with the serial port and mini USB, which is the same com port). If its RS485 you just need 2 wires (and Ground). check that the hardware configuration on the PLC is set to RS-485. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.