Oh no! Yet another wish list!
Cheap Ethernet is exactly that and you get what you pay for if you are lucky. Communications take processing power. Lots of it. So you can get cheap Ethernet without a processor or get an Ethernet card that has a processor dedicated to the Ethernet.
I would love to see a way to upload/download SQL database information over ethernet without using additional hardware/software.
Are you asking to download a SQL database into a PLC? If so this idea is nuts. I don't know of any current PLCs that have a SQL data base to upload. That would require a lot of bandwidth while transferring data let a lone the memory requirements on the PLC.
. 64 bit floating point math has been being done for years on 16 bit and 32 bit processors, the methods are well established. If its not there its either because the PLC maker believes it is not necessary or is just to lazy to be bothered, or probably more likely, justifies the latter by saying the former. Any PLC with a 32 bit processor really should support it. Granted it won't matter for 95% of the users, but it will make a big difference for the 5%.
Unless the PLC has a floating point FPU it will be expensive in processing time. Changing the firmware is easy. How many HMIs can upload 64 bit reals ( double ). It is the interface that gets tough.
Vista has been around for it seems like ever now and many manufacturers are just getting around to making the software Vista compatable. Why?? Others have been Vista compatable for 12-18 months or more.
The software developers get copies of new operating systems years before it is released to the public. Changing from XP to Vista took some effort because of the security road blocks. Hopefully it will not take as much effort to change to Windows 7. However, you should not blame the PLC manufacturers. They don't cause the turmoil. They would be happy to run on WinXP forever.
It isn't the PLC manufacturers software that is broken. It is the Vista you buy that isn't compatible.
I found that Vipa now has an Ethernet port on their Speed 7 processors that you can scan the network, (wireless or hardwired),with step 7. Step 7 finds the mac address and asks for an ip address with a subnet mask or you can allow your DHCP server to give it an address automatically.
Catching up. Automation Direct and Delta Computer Systems has been able to do that for many years now. Delta has a registered port that allows doing that over Ethernet. You plug in to the network and all the motion controllers show up. You just click on one and you are connected and IP address can be configured over Ethernet. Firmware can be downloaded over Ethernet too. That is a lot of code to have in the boot loader.
1. The ability to sync with NTP (network time protocol) servers. Seems like I'm forever fighting with clock drift and daylight savings time...
Getting accurate crystal cost money and even then they aren't perfect. Day light savings time is a self inflicted wound. Use zulu time or move to some state that doesn't have day light saving. Get your state to repeal day light savings time.
2. I wish that all Ethernet interfaces on PLCs would support plain old raw TCP for interfacing with standard networked applications.
What is a standard network application?
At some point most PLC's with an ethernet interface rely on TCP encapsulation, they should be able to transfer data this way, similar to the way data can be passed on a serial port.
Ah, so you want to transfer text and just use the Ethernet as a serial port. What does the serial port do with the data then? One can transfer binary data over serial ports too.
3. Enough memory to store comments and descriptors in the PLC.
Done, this is easy. We store comments for the steps and programs. The way we implemented this is to compress the whole project, which is in XML format, and download it into a special place in flash. It is kept separate from the binary image.
That, and I wish every PLC out there had a USB port -- wait... Not for programming, that should be Ethernet, but for having a simple place to plug in a standard thumbdrive, and upload/download a program without any need for software.
I'll second that USB port. USB has been around for twelve years now -
and legacy ports have been disappearing from laptops ever since - its about [expletive] time the PLC makers got on board.
Well which one do you guys want? I will let you to fight it out. Silly me, I should know better. You want both.
I'd like to see the day of the week represented as a number. While the processor may know the date and time, the A-B's (with which I'm familiar) do not know if it is Monday, Tuesday, etc. And yes, I do have logic running to solve this problem, it just seems it would be sooooo simple for the processor to produce this useful bit of info.
Why clutter of a perfectly good PLC with that stuff. There should be libraries similar to the Step7 libraries where you include what you need but don't force others to waste their precious CPU time do date time calculations if they aren't required.
Absolutely, and the IP parameters should be accessible and modifiable from a small LCD on the front of the unit.
No!!! That is extra money for a LCD that is used once. After that the controller is stuck in a cabinet and not seen again. What good is the LCD then. Ethernet should be configurable over Ethernet. How simple is that?
In the distant future ... I wish that there is a common object-oriented programming package that integrates al and everything seamlessly into each other. Logic code + data + alarms + hmi object + multilanguage user texts + multilanguage comments etc. A program change in an parent object shall make all derived objects update automatically throughout the project.
Would be nice if this was an open standard too. So that you could freely choose the PLC hardware vendor
Isn't that what PLC Open is all about? Can you herd cats?
You should read the threads on the embedded forums that complain about bloat code when using C++ over C. All this has a cost. It takes CPU time to dereference the reference to a reference to a reference to an object. I think JesperMP is setting the bar quite high for Bubba.
How about, when I open the controller tag browser in Logix5000, pressing the letter 'N" will go to the first tag that begins with an 'N'
It is called intellisence. It isn't that hard to implement it. I just told a programmer to do it. Seriously, it just takes time and money and a lot depends on the priority list. In our case the motion controller comes with a ton of predefined variables. It is hard to keep track of all the tag names and how the tags are spelled so something was needed to make it easier for the programmer to remember and spell the variables. On small PLCs I doubt there is the same need.
Now for my list. I think more in term of not what I would like but what would reduce the problem we see in the forum. My first reaction is usually "your PLC is stupid and you need to upgrade".
1. PLC should not cripple the instruction set of the underlying micro controller. I can easily do 64 bit signed or unsigned integer math on a 8 bit micro controller because they have these instructions
Add with carry
Subtract with carry
Shift left into carry
Shift right into carry
rotate left with carry
rotate right with carry
The carry bit makes it easy to do multi precision math. PLCs do have carry coils but no one seems to use them.
I doubt a 64 bit counter will over flow anytime soon.
Multiplies should be NxN to 2N bit in precision and divides should be 2N/N = N bit quotient and N bit remainder. There are some cool tricks that haven't been discussed on this forum that can be used your multiplies have provide a high and low register result.
Math instructions should work on signed and unsigned numbers. An unsigned add should cause an overflow error.
Rounding should be selectable. 5/3=2 is ridiculous in many cases. Encode, Decode instructions and bit count instructions should be available.
All PLCs should provide access to the hardware clock. Timer and coutners promote bad programming practice. Timers should be called delays since they really don't find the time between two events.
I think my suggestion would reduce the number of threads bit shifting, over flow, finding and counting bits etc.
And for Pete's sake, it should be against the law to sell a PLC without a toggle or exclusive or function.
