Flex727

I assume by "bit" you mean an MI operand? Did you try using the built-in filtering available for the analog inputs? There is also a filter function block available to use.

I'm using V1210 (also only has 4 sockets) to connect to 12 different remote PLCs using MODBUS TCP using only a single socket. You simply re-initialize the IP Configuration FB with the new IP Address, Re-connect the Socket, perform the communications, Close the Socket, then index to the next PLC and repeat. I allow 2 seconds for the entire process for each PLC to complete. Perhaps it could be performed more quickly, but this has been extremely reliable.

A TD timer will stop when it is no longer being activated. The other timers will require a RESET. Just use a ® coil as you would with any bit you want reset, but select the timer.

Great information!

I inadvertently answered this question for VisiLogic rather than UniLogic, but the same functionality exists.

I normally detect and log power off and power on conditions in the software I write. I do this by storing the date and time in an MI vector on every PLC cycle. On power up, I use the SB2 bit to prevent storing the Date and time to the MI vector prior to logging the power off condition. This provides the last date and time stored, which was at power off. Then, I log the power on date and time, also using SB2. From that you can determine anything you need, such as the length of time the PLC was powered off. Regarding where the PLC was in the program loop at the time of power loss, operands retain their value through a power loss if the battery is installed and working. If there are critical intermediate steps, you can keep track of them with operands that will tell you where you are.

There is absolutely no reason to chain all that logic into a single ladder rung. This forum topic is "Best Programming Practices" and it should be noted that every bit of added complexity in a single ladder rung increases the chances that the compiled code will not be what you expected. In this case, it SHOULD all work, but why do it? Your example should be broken into 3 ladder rungs. Also note, you don't need SB1 (I find SB1 to be very useful to chain items in parallel, but you don't need it here when everything is in series), and MI20 is counting up to 6 seconds, not 60 seconds. Is that what you want?

This was simple enough that I just threw together some code rather than try to explain what to do. Feel free to ask if you have any questions. It may not be exactly what you're looking for, and I generally buffer inputs and other niceties that I didn't do here, but you should be able to figure out what to do from looking at this. stevennoppe_Samba.vlp

Frankly, I've never tried to place multiple subroutine calls in a single ladder rung - perhaps it works, but there is no reason to do that. Separate the calls to ALARMS, FUEL & TRANSFER SYSTEM, and POWER PLANT into separate ladder rungs. Further, when MI 0 is equal to 219, you have an ambiguous situation. When MI 0 equals 219, should MI 13 equal 0 or should it equal 1?

A couple of things to check: 1) Perform Menu Edit/Find Operand... and look for MI 13 to make sure it isn't being overwritten elsewhere in the program. 2) If this ladder rung is in a subroutine, make sure the routine is being called.

Is there any chance Unitronics is considering updating the Ethernet Communications Module (V200-19-ET1) for the Vision products to match that of the ethernet in the V700?

Unitronics offers a training/certification class to be a Certified Unitronics System Integrator. It's a good class and I can recommend it.

I have to agree with sgull. I have never had a field failure with Unitronics products and consider them on par with products that cost substantially more. Electrical noise can affect any electronic component and can be compensated for.

I don't know if you really need the PLC to be the Master, by try it the other way first. Initialize the PLC Socket to Port 20256 and Slave. Set up the PC communications in VisiLogic to TCP/IP (Call). Confirm the PLC Name and IP address are correct, then try to initiate communications from your PC.

Be sure your PC and PLC are set up on the same subnet (e.g. 192.168.1.xxx). Check in INFO Mode what the IP address of the PLC is and the PLC Name and be sure those are properly entered in the communications section of VisiLogic. Make sure you are connecting the PLC and PC either through a hub or with a crossover cable.

There are quite a number of example projects that come with VisiLogic. Have you looked at those? They can be accessed through the top line menu: Help / Examples...

There is an Enable Data Entry tag you can use. Leave the Read Only box unchecked then use the Enable Data Entry tag to enable or disable data entry to the Numeric Box as needed.

Please send your contact information to me at blanier@arc-controls.com. I'm interested in taking a look at what your requirements are for this, as I believe I can help you and this looks like an interesting project. I am certified by Unitronics and have substantial experience in writing software to automate chemical delivery systems. I look forward to hearing from you. Best regards, Barry Lanier

How are you trying to connect to the PLC?

Any of us who consider ourselves real programmers are always looking for the most efficient, economical, and clever solution to a programming problem. But in reality, it's probably more important to write the code in such a way that it is clear and understandable to another person trying to read it. I like using a State Machine, when applicable, because it's very clear what is happening and it's very clear where in the algorithm you are when online with the PLC. Another side benefit is that it forces you to do what Joe Tauser suggests - organize and document your logic. I do other things, such as group similar or related short pieces of code using SB1, as follows: SB1 --| |-- <one line of code> | <another, related line of code> | <yet another, related line of code> This minimizes the number of ladder rungs and helps readability. Another important thing to do that surprisingly many people don't is to name the Operands in such a way that it is VERY obvious what that operand does. A few extra keystrokes today can dramatically reduce the time spent trying to understand what you were doing two years ago when you wrote the code and now have forgotten. I learned early on NOT to use the "Links & Jumps" tab to link operands on pushbuttons to jump to different displays. You will inevitably forget to enter one in the provided field. What I do is have a Subroutine called "HMI PBs" where I enter every display jump condition (I use a single MB for each display I will be wanting to jump to) and then everytime I have a jump PB in any HMI display, it will already be in the code and there is nothing to remember to make it work. I have an HMI screen where I display the vlp filename and the Visilogic version number so that I know what file and version was used when the PLC program was last downloaded. It also includes important information like the PLC Name and the Ethernet address, when applicable, so that it is handy. I always use Input and Output buffering, this can be important when the hardware unexpectedly has to be changed (change I/O module, or the technician mis-wired something). It also makes it easy to troubleshoot using an extra bit that can be controlled while online, or on a special screen, without having to "Force" I/O. I turn OFF access to INFO mode (set SI50 to zero) to the customer, unless properly logged in (I use multiple login levels on every program I write). This helps prevent problems. When access to INFO mode is needed I use SB36 instead of changing SI50. I also provide a button for a soft reset (using SB300) so the customer doesn't have to power cycle in the event of a system change or problem that necessitates a restart. This is off the top of my head - I'll add more stuff as I think of it.

I don't think tonymony was complaining about the lack of C++, but was merely explaining that he is transitioning from C++ to Ladder Logic. Tonymony, the picture you posted is too small to tell if your logic will work, but the way I would do it is to simply Store Direct either the number 1. 2, or 3 into an MI depending on whether I1, I2, or I3 is on, respectively. You can then use List of Texts, or List of Images to display the information on the HMI screen. There will be more complexity if 2 or more of the inputs can be on simultaneously. I1 1 MI0 -| |---------Store Direct-- I2 2 MI0 -| |---------Store Direct-- I3 3 MI0 -| |---------Store Direct--

Yes you can do that. Socket 1 will default to Port 20256 for PLC-PC communications. If you initialize Socket 1 to a different port, then you will need to initialize one of the other sockets to port 20256. Be sure you also use the PLC Name function block to give the PLC a useful name for communications from your PC.

Are you starting at 7000 hex (28672 in decimal) for ML0?

Did you re-test the bad PLC immediately after you successfully connected with a new one?

Then you will need 24 volts. If a 24 volt battery is not available or practical, buy or build a DC voltage booster.