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hotwires

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Everything posted by hotwires

  1. Improvements required

    I've got my head halfway around this. Guess you'd have to draw me a picture (joke). barrier is still in terminology. i have a fair grasp of hardware and the architecture of data processing. programming launguages not so much, to many dialects/flavors out there. Pyrhon and PBASIC are only ones I ever actually wrote anything in (and it was nothing vast). I recall Dan Logee explaining the UDFB (local, Function In, and Function out) tags were processed in RAM and never occupied EEPROM (non volitile) memory until outside of the UDFB's process. Is this in anyway analoguos to "passing" by reference versus value? To me passing rapid change in velocity to overtake another automobile on the roadway. or please pass the carrots, or passing a kidney stone. The English langauge is riddled with abiguity
  2. Silly coincidences make me jump!

    Aus, Inevitably some piece of equipment will fail in the same area you were working about an hour after you leave. Then you phone rings, then you explain how you didn't touch it and that it is in no way connected to what you serviced or installed, and then you hear: "but it was working until you showed up". Then you decide if you should: go into hiding, go back and troubleshoot something you shouldn't be messing with, or wait for other folks to show up and confirm that it had nothing to do with you. Fun times. Happens at least once a year to me. I would not advise slashing your wrists. Usually finds resolve within 24 hours
  3. Newb questions-analog scaling/PID setpoint

    You can enter your own scaling ranges direct in the AI setup section. This is addressed in past forum posts and was also discussed at a training seminar I attended last year. Joe is correct, this forum is primarily composed of fellow programmers (from novices to experts) who have day jobs. Usually within 48 hours you will have a reply. If it is urgent and a weekday I highly recommend calling Unitronics technical support. They will do their best to give you an answer on the spot or within 24 hours if it's a complex or unprecedented issue.
  4. @Ausman i stacked HMI numeric displays od MODBUS RTU STRUCT INT: sessions, success, fail for each of the four RTU's. Incrementation was not sequential in regards to order of slave ID's
  5. Unistream's periodic mode internal sequencing logic (no idea what it is) may have something to do with erradic operations when adding a second slave. I have a program that polls four RTU (RS-232 over RF) slaves and polling order is RTU 1,3,2,4 not 1,2,3,4. Thought this was odd. I poll once every 45 seconds. The RF modems add up to 500mS latency. Offsite pump control doesn't demand high speed updates.
  6. Thoughts on Linux

    Win 7 and up you can create a system image on an external HDD. Drop computer in pool? System image restore. XP had no simple complete OS backup.
  7. Silly coincidences make me jump!

    @Cara Bereck Levy "fusible link" is the term used in the US automotive industry for a length of wire intended to act as a fuse. Happy New Year Ms. Cara 🎉
  8. @Joe Tauser I didn't forget the architchtural structure of MODBUS. I used terminology like: " request packet / response packet" and "exchanged". No data communication is instantaneous (maybe quantum computer would be closest thing I can imagine). I also remember JT qoute: "empirical data is the best data" and wholly agree. My time calculation figured in the send and reply packets (approximations) but NOT: UART, CPU, or ladder execution times. 17 mS is still a far cry from over 500mS. I don't have an intimate understanding of physical PLC processing architecture, however I assume (dangerous word, I know) that it's fairly parallel to PC's and embedded uC or uP (with external chips) control devices (like DMX lighting control consoles and BASIC stamps). Unitream has two CPU's? correct? Panel and CPU, then RS-232 module has UART with CPU that is on a com bus back to the main brain. If I ever get some spare time I'll try to setup a Unistream RTU master to Vision RTU slave and try to measure min time between successful RHR exchanges.
  9. Just a thought: you could try aperiodic ladder trigger on sensor #1, compare for increment of RTU#1 sessions STRUCT integer, that in turn triggers Aperiodic RTU#2, compare detect session STRUCT advancement, in turn triggers RTU#1 again, LOOP. In THEORY this should alternate MODBUS commands between sensors at the rate each MODBUS slave STRUCT count advances. Would be analogous to the MODBUS "function in progress" bit in vision. The system would tell you when it had completed a MODBUS operation, that being the cue for the next. Never tried this exact scenario. I have used session counters to detect a complete cycle of periodic MODBUS exchanged and toggle heartbeat bits. Assuming: The request packet for the Slave address (1 byte) + Function code (1 byte) + Offset (2 bytes) + Number of Regs (2 bytes) + CRC (2 bytes) = 8 bytes. The response packet length will be: Slave address (1 byte) + Function code (1 byte) + Byte Count (1 byte) + Data (2 bytes) + CRC (2 bytes) = 7 bytes. The number of bits will depend on the serial setup (e.g. parity, data bits etc.). Assuming 1 start bit, 8 data bits, 1 parity bit and 1 stop bit = 11 bits per byte. So total number of bits = 15 bytes * 11bits/byte = 165 bits. Now the bit time must be calculated = 1 / baud rate. Taking 9600 baud as an example, bit rate = 9600 / 1 = 104 micro seconds per bit transmitted Giving a total transaction time of 104 micro seconds * 165 bits= 17.16 milliseconds per MODBUS handshake Now there is some internal overhead in CPU to chew it up and spit it out. What part am I missing that makes less than 1 second polls feasible? One thing I'm not factoring in is the response turn around time in the slaves. That would have to be measured or found in spec sheet.
  10. Isn't the ethernet module just a (physical layer) signal interface board? I was told the other Vision/Samba controllers didn't have enough memory to accommodate more than four sockets. V700 must have a unique CPU.
  11. Silly coincidences make me jump!

    I am particularly jumpy when working in or around high voltage electron tube power amplifiers. Even little sounds startle me. I've had other people clap or make a loud bang while I had my head in an equipment cabinet, NOT FUNNY AT ALL! Amazing how the timing can go when you shoot the juice to equipment and something else goes bang, pop, bing, bang or boom. Heart arrhythmia's can certainly result from such events. Happy New Year Aus!
  12. General.VNC Number Of Connections INT32 on a Unistream 15.6" is linked to an HMI numerical display and the "connection counter" seems to be cumulative instead of real time. Right now it is showing "D#6" and there is absolutely NO WAY there are six active sessions at this instant in time. UniL version 1.19 rev 19. Have noticed this for about a year. This in no way inhibits crucial functionality of the process control, just a nuisance to me. In short the VNC connection counter seems to get STUCK. A reboot will zero it back out. Sometimes it works as expected; ie showing zero, then 1 when I connect VNC and back to zero when I disconnect.
  13. UPDATE: I found that SI104 (socket 1) was not set in my SAMBA program, guess I'm thinking of some of the V430's I had tried setting SI 10x values. I set power up value D#10000 for SI104 (10 sec). I'll see how that works out. bad thing is the socket freeze doesn't happen often (can be weeks or months). For some reason I had the impression that SI101 thru SI110 did that for you: SI 103 TCP/IP Connection Keep Alive (Socket 0) Units of 100 msec Note- When value is ‘0’, the function is disabled Enables the PLC to disconnect if there is no communication from the connected device. When TCP/IP connection is established (SI 145-148 = 6) check data transport (SDW 14 – 21). If no data transport occurred during the defined time – perform ‘Socket Init’. Data Transport counter is SDW 38
  14. Great, not sure if it will present in a LAN environment or not. All VNC clients are on WAN side. Router is DMZ to PLC (panel) IP. My only theory is when multiple clients connect at the same time (which can happen) and then disconnect in random sequence that (perhaps) PLC not detecting disconnect. Not really sure of the mechanics of a VNC session disconnect on host side. I know at 2am that six clients are not still connected. Mobile devices are mostly iphones, if that helps. Operators spot check panel when they get a text msg alarm. Doubtful anyone is staying on 24/7 via their cell phone. Thanks for looking into it😀
  15. Is there any chance of the future holding a feature that would compose reports to printers? something to the likes of the email message composer. put in text, variables, etc and have a ladder FB that when triggered would send out to a printer via USB or TCP? I know there is an example file for a TCP printer, I've looked it over, not live tested yet. It's complex to say the least. I would love to get my Unistream client daily reports printed out direct from PLC. The old Foxboro round paper charts with the red ink go in the garbage on most upgrades, the onscreen displays (trends) and emails are great, however some still like/require that data on paper. Paper: that nostalgic, almost extinct white stuff.
  16. Improvements required

    I can relate to item #3. Things get a little wonky when you start deleting and inserting news alarms. I know, I know, you should have a list of every alarm in a logical order before programming... however sometimes things change/evolve or you have the inevitable programmer who just "free styles". Another far out wish would be to see direct alarm to email generation. I've built out ladder to pair emails to alarms ENTERING and EXITING active states. It's not that it's difficult, just time consuming. Drive behind the majority of my feature suggestions is purely based on time savings for the programmer. The Unistream sales literature uses "50%" less development time" phrase. I really couldn't begin to personally quantify the time savings into a percent. Is it better than everything else I've used, YES, hands down. Kudos to UniT for that. The world will always want: bigger, better, faster, more.
  17. This is over my head. can you paraphrase? I hope to do a major update to one of my UniL programs and a UDFB with comparators and S/R logic will come into play. A stack of less than and greater than compares linked to set/reset coils (pump state control PV vs setpoints), want to repeat logic for two water tanks. If you could clarify the context of the phrases; passing, reference, and value would help.
  18. At random times sockets 0 and 1, 20255 and 20256, server (slave) on V430 and SM43 are freezing up. Usually not both.... thinking it's more port 20255. I've played with the SI for timeouts. SB168 is set to power up at "1". it will still email, web server (V430) will still work, and usually port 20256 will work to let me connect and remote REBOOT the PLC, then the frozen port comes back to life. Any ideas!? I worked a long time on getting a reliable "EMAIL" logical construct; I believe I got that whipped and have had no issues lately. This STICKY PORT issue has plagued me for sometime. Any suggestions/solutions would be greatly appreciated.
  19. Improvements required

    wow, that's a comprehensive list. I'm still petitioning for: alarm suppression per alarm instead of per group, MODBUS mixed R/W function compatibility with Vision, and I miss the drum sequencer found in Vision. I agree the Unistream line is amazing, just find it odd that it wouldn't/ couldn't replicate all the features found in Visilogic plus all the "not possible in Vision series features". Yes I know the Unistream platform is Linux based and I'm sure this presents some significant differences from how Vision does all it's stuff. Linux platform has a lot of modules preconstructed like VNC and MODBUSlib which I'm sure equated to developmental time savings. And yes: I know there is potential to self construct all types of custom functionality with UDFB's etc... but as a ladder programmer (no C+ code knowledge) I am looking for time savings with FB's (which Vision is loaded with). Now we find ourselves with wishlists. All in due time hopefully :-) Just having our input reviewed directly by the R&D team is awesome. With most other brands these things aren't even open for disscussion.
  20. Odd that one shots wouldn't set/reset coil. Can't argue with a model that works though.
  21. Combining two trends

    Make a third trend with it's source an integer that is the mathematical sum of the two individual trends. I did this on a Unistream with 3 filter flow rate curves and a fourth curve the sum of the three.
  22. Good advice Flex. If the "float_start_command" bit has a reset coil somewhere else in the program it will interfere. One instance of a coil (RLO or S&R) per tag, per program! Is there any special reason you put float switch latching logic into a UDFB? Is it something you are reusing in the program for multiple tanks? I was not aware function in tags would not allow transitional contacts.
  23. Try making float_lower contact in rung one a positive transition contact and the NC (XIC) in rung 2 to a negative transition contact (NTC). See if that gives the logical behavior you were expecting. As it stands right now you're float_start coil will (unconditionally) go false as soon as "float_lower" NC contact goes false.
  24. agree with Flex, you need to "one shot" the toggle coil (per event). otherwise it will toggle every scan for the durtion of the event.
  25. I recall the old simplex school clocks synchonizing from a master clock that sent out a 19kHz signal over the AC building wiring. It controlled the bells also. Maybe some BASIC STAMPS and DTMF codes (master send, slaves selectivly or collectively receiving). would be easier if devices were DC powered, a bias tee to inject signalling AC. Just thinking cheap. Not off the shelf there are protocols out there for such: https://en.m.wikipedia.org/wiki/Power-line_communication however unknown on compact, low cost hardware. Sounds like something an audrino, raspberry pi, or parallax basic stamp could be programmed to do. I generally loath anything that is "trendy".
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