panic mode

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About panic mode

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  • Birthday 12/15/69

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  1. Emerson (Prophecy) vs. Rockwell (A-B) Lets be real...

    acquiring another skill is always a plus and you never know when it will be handy. more importantly, continuous learning helps one be flexible and open to change. i have worked with many PLC brands (AB, Siemens, Mitsubishi, Omron, Beckhoff, Schneider, etc.). knowing any one of them would be more than enough to keep me busy and employable but that never stopped me from trying to learn more while trying to retain as much as possible. as a result PLCs are important but only a part of what i am good at. i like learning and and would not change a thing. knowing more gives me the edge. also there is a freedom to choose even when things get hard and others may be struggling to just stay afloat. when there is a shakedown, first to go are the temp workers and those with limited skill set. and i have seen many people come and go, while i move when it suits me - salary, benefits, hours, travel, work climate, location, etc. so everyone has unique needs and should decide what works for them. if you think it is the best for you to move on, don't let others stand in your way. change can be good but even if there is a regret, it is better to be because of own choice, than someone else's influence. 
  2. so doing 4 or 5 passes can give you X axis range of 880-1100mm  so some measurements are needed to verify data transfer, PLC scan time, IO refresh time and valve response time. modern PLCs are quire fast, Ethernet messages are not big deal if you transfer data in reasonably sized chunks. transferring all at once requires a lot of memory and also it is going to take long time. Depending on used platform and implementation details streaming may or may not be perfect because you also need to take care of pretty tight timing on numerous outputs. the PLC logic should be fast. this means not dealing with valves individually (bit by bit). it would be better to use block move to write data to all outputs at once, wait a bit (make this adjustable), then clear all outputs the same way. and this could be done in an interrupt to get best possible accuracy. If the streaming of data does produce issues (scan time glitches and inaccuracies in the print) one options is to simply not transmit while print is in progress. In this case you would need to transfer and buffer all the data for that one full pass in Y-direction and this is done every time before the Y axis moves - transfer would take place while X axis is moving because no print is in progress at that time. that means you would need to transfer and buffer 11bytes * 400 samples = 4400 bytes or 2200 words. all of this is very doable.
  3. i am not quire sure i understand the details of what you are trying to do. for example what is the total work area (length of X/Z)? that could explain why would data file need to be so large. 20mb grouped in 16bit points means up tp 10485760 points or canvas of 3238x3238 pixels. so yeah.. to me it sounds like you are developing something that paints murals or billboards and the 88 valves are an array of spray nozzles for different colors. if so then why not use just few of them (CMYK or RGBWK) instead of 88. also 16bit value is sufficient to control 16 points but it is not sufficient for addressing 88 valves that you require. that would require 88bit (or 96 bit). conventional industrial PLCs are not very good for this. one of the limitations is scan speed as well as IO speed. also most PLCs would have hard time with that large data file but chances are things can be optimized. so getting to know real requirement is the key. next one need to focus on hardware. perhaps there is no need to dump entire file to PLC - how about sending enough of data for one line scan only? if commercially available products do not meet the needs, one can make custom hardware to do pretty much anything.    
  4. spring only gets to do something after there is no more current in the coil (magnetic field collapses). as long as coil is energized, spring is not in control. so after output is off, current still flows through solenoid (but now it is going through diode, not the output). this is due energy stored in solenoid and duration is affected by characteristics of suppression device. and as mentioned already, connecting MOV or Zener across solenoid will not produce any meaningful difference if output has own built in diode (and normally they do!). and if not but you choose MOV and Zener with too high breakdown voltage, the output device will get damaged.   
  5. a very good point, i would add that MOVs do not apply reverse voltage, they are passive component and do not store energy - they just conduct more at some higher voltage. depending on used product, this value is different. the higher the clamping voltage is, the shorter the pulse is (turns of faster). diode has Vf of only 0.7V so the clipping on 24V solenoid occurs at 24.7V. That is extremely low and takes longer to switch off. But with MOV it may be at 36V or so. using Zener diodes one can get the same effect which is why there are several options to choose from.
  6. MOV H400 K4M60? Hexadecimal

    exactly
  7. and just got call back from support. i was told that this is a known and not fixed issue in version 2019. one should consider upgrading SWE to 2022. how convenient...
  8. Hello everyone, have not done panel design in a long time, I am not used to SWE, was using other products in the past. and actually everything is going well expect when trying to insert 3-level terminal blocks. single and two level terminals work fine, issue i am facing only appears with 3 level blocks: while only one of three level is used, things are still ok. but for some reason as soon as another level is used, SWE interconnects all three levels (making them same equipotential) then adds further and non existing levels (4th, 5th...). at first i thought something was wrong with the parts i defined but the same happens with any 3-level block. any ideas?  
  9. None payment demand.

    and that is why such measures exist, someone was burned before. which is why i consider any tampering with such measures equal to theft. hence do not want to be part of it.
  10. Analogue Output Failure - Why?

    normally the only reason any output fails is because its specs are exceeded. so either something is connected incorrectly or there is an intermittent problem in the cable or target device. to me this looks like an intermittent problem that causes some short (not necessarily GND, could be also the 24VDC etc.). if the root problem is not found, switching to another output will just lead to inevitable - again and again. the analog output card are not cheap.... adding an isolator should protect the PLC analog output but the isolator itself may still be damaged if problem is not fixed. but since you have already replaced both cable and the positioner, this is most likely fixed - hopefully permanently. i would still be inspecting the entire length of the removed cable and each and every termination as well as the old positioner. if this does not yield results, there is a good chance the same thing will happen again. and if that is he case i would probably consider adding in some extra protection...  About protection: the datasheet for Q68DAIN shows that load can be 0-600 Ohm. so zero Ohm load is ok. it also stated that short circuit protection is available. So short to DC common is not a reason that outputs were failing. It must be something else. And that something else could be another circuit... Normally analog IO are using shielded cables and they tend to be done with single cable from PLC to the target device, with shield connected to ground and DC common in one place (at the PLC cabinet). This is pretty much the practice we used on numerous projects, some with thousands of analog IO points and very long cable runs, never had an issue (used to do controls for chemical plants).  But when that is not the case, the best bet is to scrutinize the wiring methods. Any split (multiple cable sections, shared terminal strips, shared multiconductor cables, routing near power cables or sources of EMI etc) is potential problem and therefore a red flag that requires closer look.  good luck...   
  11. None payment demand.

    👍
  12. None payment demand.

    maybe so but i have been asked before (twice to be exact) to do same thing on equipment with another brand of PLC+HMI. when i saw the message i asked them for proof of ownership, which of course they did not have, so i walked away. if they did not want to pay someone else, why should i expect they would pay me? and why get involved into something that may turn ugly and violate some property rights? but you are welcome to do your own thing, i have plenty of work with nice people, don't need to wrestle with pigs or possibly engage in theft.  
  13. None payment demand.

    this is something used to rent equipment and ensure payments are in. clearly this is not something that author wanted others to touch, so why get involved? if something on equipment fails, then company that owns equipment will be the one to deal with repair/replacement. 
  14. SPI interface for FX3U-14mt?

    Mitsubishi makes expansion module for it (FX3U-4AD-TC-ADP) but not sure if this can work on the clones or how much convincing it would take. low level interfaces like SPI, I2C etc are used for chip-to-chip communication, this is meant to be interfaced directly to MCU and exchange data serially at high speed. PLCs are different animal and may not have suitable GPIO exposed... and i see no interface on that board, everything is already conditioned to appear as PLC IO. then there is an issue of a missing driver. One could still choose to use PLC IO but in general they are operating at different voltage levels so hardware interface adapter (level shifting) is needed. Plus PLC IO are way slower than MCU GPIO. I have still used this on occasion to interface some industrial controller to otherwise incompatible devices. it can work but it requires one to write own code and as mentioned, this is a crutch and tend to be painfully slow. For temperature this may not be an issue as temperature changes are among the slow processes. Good luck...   BTW, there is tons of online resources on SPI, this is one of simple interfaces that can be easily implemented even on platforms that do not include hardware port for it.  Finally, your version is MT (transistor output) so it is tempting to use them as PTO but the issue is that high speed inputs are simply counting received bits, not storing/shifting the value. In other words - slow it is.  You just need two outputs and one input. Input is used to read the data from chip. Outputs are used to select chip (also works as reset) and send clock. on every clock sent you need to read the bit. in this case there are only 16 bits to read. if your PLC scan time is 10ms, you can create clock with 20ms period or 50Hz. So theoretically you can read the temperature value in 18*20ms=360ms which is not too bad... 
  15. TCP connection from a client to a modbus server only needs IP address of the server. Port is always 504 502. Server is always supposed to run. Clients can connect, exchange messages and eventually close connection. Same is with this forum. it runs on a server. if the server is down you cannot use the forum (your web browser is a client). Inside PLC, modbus server instruction has fields for transmitted data (read/write).