Flex727

In VisiLogic from the menu just above the ladder window, go to FB's / Loadcell / Help and it will take you directly to the Loadcell help page. There you can learn all about configuring, calibration, Tare, etc for your Loadcell module.

When you say "remote session", what are you referring to specifically?

Any critical value that the programmer knows will not need to be changed by the user should always be set in a power-up. That should be SOP.

I don't use UniLogic often enough to remember enough detail to answer your question definitively, but one universal solution is to incorporate a "heartbeat" function within your communications. If the heartbeat stops changing for the appropriate period of time, then reset your bits (or registers).

This is silly. You want flash memory to store data in the PLC? Unitronics has supplied the facility for adding flash memory to the PLC. An SD card is just additional flash memory for you to use as needed or as you see fit. Nothing artificial about it.

Yikes! Which PLC model?

Quit making me feel like an old man - my joints already do that!

Require a password to change the value of SI 50 or password protect a button for SB 36, or place the button on a screen not accessible remotely.

You can also save all the Operands to an SD card. You can do this from ladder and it only takes seconds for the operation to complete. You can also save a complete clone file to the SD card but that can take several minutes.

You can already do that: assign a power-up of zero to SI 50.

Multiple problems: 1) Get rid of ladder rung 2. The SCAN_EX FB is for when the PLC is the slave. 2) With MODBUS you need to CONNECT to the slave device. Check the example projects that came with your VisiLogic installation to see the proper procedure for performing the connect function. 3) It looks like your vector that receives the data, starting at MI 12, is of length 4 yet you do not have 3 additional unassigned MIs for the data to go without overwriting MI 15.

The Socket Initialization FB determines master or slave. Ignore the "Default:" statement in the MODBUS configuration FB. It is true that is the default, but the Socket Initialization overrides. You can use any of the 4 sockets for any purpose. Just initialize them the way you want them. It's best not to have two or more sockets set to the same port number. As I said, you appear to be using Socket 3 for your comms, but you are configuring your MODBUS to use socket 2. Change the MODBUS configuration to socket 3. And again, ignore the "Default:" statement that appears there, just choose the correct socket number.

Many years ago (many, many) when I was young and stupid (okay, slightly less stupid), I had some confusion about PLC Ethernet comms (didn't we all?). I had the need recently to have another look at a program I had written back then. This program, running on a V1210, exchanges data with several V570s simultaneously using MODBUS TCP. Each connection uses a separate socket, but all 4 sockets were initialized with the same port number, 20257. This program is still in the field and running flawlessly. My question is, why? How is it possible for the communication to work properly when all the sockets have the same port number? How does it all get sorted out properly so that the data ends up in the correct place?

Your VisiLogic installation includes a number of example projects. In the VisiLogic main menu, go to Help/Examples.../Version 900/Project Examples/Communications/MODBUS There you'll find examples you can review and adapt to your situation.

And by the way, this is a volunteer user forum, not official Unitronics Support. Unitronics does provide support elsewhere.

It looks like you set up Socket 3 for comms, but you set up your MODBUS configuration for Socket 2.

Also, don't get confused between your wired ethernet address and your wireless address on your PC. When you do IPConfig in a command window, confirm which address is which since they are usually on different subnets. You want to make sure you use your wired IP address subnet.

That is your Subnet MASK, not your subnet. Your subnet is 192.168.0. You need to make the subnet match between the PC and PLC (the first 3 octets must be the same and the 4th octet different). The subnet of the PLC, as you show above is 10.2.5. Also, are you certain that 10.2.5.83 is the IP address of the PLC? Even so, go into UniApps and change it to 192.168.0.xxx (anything other than 71). Or, you can go into your PC network settings and change your PC IP address to 10.2.5.xxx (anything other than 83). Once you do that you should be able to communicate if you are plugged into the correct port with a crossover cable or through an ethernet hub.

Is your PC on the same subnet as the PLC (10.2.5.xxx)? Also, are you plugged into the correct Ethernet port on the PLC? Are you using an Ethernet hub or a crossover cable?

Still broken.

Broken link.

TA timers need to be Reset manually. They do not reset automatically when power is applied as TD timers do. Put in a reset and your TA5 current will be correct.

It's actually the exact opposite. The router is set to forward port 20256 from their public IP address (WAN) to their to their private IP address (LAN). This is actually fairly common, and while it's not secure, it's generally okay because there is little incentive (profit motive) to hack in these situations. Tensions in the ME provided the incentive absent a profit motive. It's a good lesson learned here - avoid using default settings.

Saw a report on ABC News this morning about a drinking water pumping station in Pennsylvania being hacked. The photo was clearly a Unitronics V570 PLC. Unitronics, among others, is being targeted and we need to be acting immediately to prevent more occurrences. We need some guidance from Unitronics right away.

True, but I'm having difficulty imagining another point of attack. If there is, then Unitronics can circumvent with a firmware upgrade.