panic mode

MrPLC Admin
  • Content count

  • Joined

  • Last visited

Everything posted by panic mode

  1. Analog Scaling Problem

    no... without changing hardware you can double resolution if you configure input to use voltage instead of current (if the sensor can output voltage).  if you need higher resolution, go for  FX2NC-4AD (means selling existing system and buying another)
  2. Controls system - what to choose  
  3. Convert F930GOT to F940GOT

    Same way you convert Toyota to Lexus...  Which means you don't... The best you can do is sell one and buy another...
  4. Not sure if this was mentioned before and if you may have run into this but I just found about it the hard way and I am not happy about it. Everything was going according to plan until I tried to make some room and temporarily undock and float Controller Organizer in RSLogix5000 so I can see more. But the Organizer immediately disappeared. Alt+0 and clicking on Organizer icon and menu entry made no difference. Restarting application made no difference - except that now even programs I had open are gone. Restarting computer also didn't help and there was no option to rearrange windows to default view. The trouble was I was away from office (in fact i was in another country) and without installation discs or even internet access. On the plus side, operators were called to attend some training so line was shut down for about 3h. It turned out that couple of weeks ago I was using dual monitor setup to write some code. RSLogix apparently remembered window positions and as soon the Organizer was undocked, it was moved to "old place" even if that was off screen. Since this time I did not have second monitor, I could not see or access this rogue window. A colleague complained of encountering same problem with error window. The code he was working on apparently had error and would not compile and there was no way to see what the error was. Now I know not to undock windows unless I have access to external monitor (or to move all floating windows to main display when using second monitor). And if it does happen again, I know that borrowing second monitor can help resolve the issue. I hope Rockwell will do something about this and fast.
  5. Scaling question

    please respect Sir Isaac Newton, unit is Nm (Newton-meter) not nm (nano-meter). in general units named after people are capitalized.    what input did you use? was it DINT as well? show code...
  6. i think the goal is to use generic TCP/IP message to communicate with a non-AB device (laptop, AtlasCopco etc.)
  7. need an advice..

    can you be more specific? what do you see as a carrier?  if you are interested in automation, PLC skill is a must but there is also robotics, motion control, networking, etc. technology is constantly changing and IoT is getting more wind. if you see yourself as a business owner some day, there would be other skills that matter.
  8. COP instruction copies one more elements from one location to another. Equivalent in this case would be using four MOV instructions. This is well documented.
  9. ASCII Question

    break problem into smaller ones and test each separately. for example, test STOR with own data first, not with string received from scanner. this will give you opportunity to see how instruction works (always get familiar with each and every instruction before using it in real program).  5 characters is ridiculously short to receive a string from scanner. there will always be misread scans etc. five characters is probably just enough for overhead and padding. you can trim it down later but i would say go for 30+ characters while developing. check your code... you only show one instruction but is this really a sample or changing data, index is clearly invalid. lookup GIGO principle        
  10. ASCII Question

    how is the UDT declared? why is the LEN so large value?
  11. ASCII Question

    are you sure that instruction is called? i see no green rung before it...
  12. can not open a program

    the file you are trying to open may be corrupt or different format (created in newer software for example)
  13. Mitsubishi GX Developer

    issue with totalizers is that results grows and normal data storage in PLC has limitations (32-bit register size for example,). real numbers have  larger dynamic range but set of own peculiarities (fewer significant bits etc). this means that exact implementation will depend on application and you did not provide any hard data or constraints so it is unlikely that any offered solution will be fit for your application. one simple totalizer is to use clock of sufficient rate (1sec for example). then on a rising edge of that clock add current measurement to a total. that's it. to interpret data, scale it accordingly taking into account sampling rate.  
  14. All in one: PC, PLC and HMI

    yes, it is called PC.... you can do anything on PC if you know some programming. otherwise there are softPLC and HMI packages that you can buy and install then it is no different than working with conventional PLC or HMI  
  15. Average motor speed

    you can use timer to sample speed periodically (using some regular interval, say every 0.5 sec). Goal is to count all samples (N) and also sum them all up (Total). your average is then just a ratio Total/N if you want running average that ignores stopped case, you can use current average instead of sample value when computing Total. another option is to ignore it but in this case you also must prevent incrementing of sample count N.   if process is long running, total can reach large values and this would have to be handled.   
  16. SInk plc input module

  17. SInk plc input module

    theoretically yes... if both products are made by companies using same terminology but "sinking/sourcing" is not used consistently and if i recall it is the AB that uses it backwards from others this is why it is better to use PNP/NPN terminology or double check datasheets.    
  18. SInk plc input module

    "sinking plc input card" and "NPN sensor"? what are the actual products you plan on using?
  19. Factory Talk Directory Blank

    Licensing issues, copy protection and similar are to be resolved with product vendor.
  20. Multiple PLCs to a single robot

    Which robot? Kuka KRC4 controllers using EThernetIP can act as a alave for up to five masters (and still be a master itself)
  21. Download program to Micrologix 1400

    RSLinx is not free, but RSLinx Lite is and it is commonly included with other products like RSLogix etc. Both full and lite versions will do in this case.
  22. PLC Interview Questions Help

    he may be chickenkiller but i am a chickenconsumer 
  23. PLC Interview Questions Help

    i don't see many Germans in this forum. what do "PLC programmers" actually do in Germany? only programming? i ask because i worked with several integrators from Europe (Germany, Italy, Czech republic etc.) and was a bit surprised. so far my impression is that everyone on their team is very narrowly specialized...  do they require teams or can they function individually? and if they are indeed mainly focused on PLC (and only one brand like Siemens), they better be dang good with it, i would want to some real magic and fast. also what kind of experience you need - low, medium, high? robot and plc programming has a lot in common: + both use I/Os, fieldbusses, networks and programs + both use same simple data types and arrays, data conversion/casting is a very common thing + ask about SCAN, in case of KUKA robots, background process (Submit interpreter) is "SPS" or PLC. but there are differences in regularity of scan + robots only rarely use analogs, but on PLCs this is quite common, Siemens has some quirky configuration for this etc.   for entry level positions maybe just go with basic questions like toggle (flip-flop) where button is used to change state of output, using timers, combinational logic etc.  for mid level i would expect to see some math, including custom data types (structures), custom functions, parameter transfer, using arrays (recipes for example), sequential logic etc. for high level i would expect to see some serious data manipulation skill in any programming language that target platform supports, sorting arrays, (at least one dimension), using ring buffers, stack, optimization, processing large blocks of data efficiently (for example processing data at word-level, not bit-level)   
  24. you need to look at IP and MASK values in a BINARY format and with just few basic rules you will see why: 1. IP address is actually two addresses - Subnet address and Node address, Subnet mask tells how the 32 bits representing IP address are divided into those two addresses.2. 2. part of IP address that corresponds to Subnet address is determined by field of "1"s in subnet mask 3. part of IP address that corresponds to Node address is determined by field of "0"s in subnet mask 4. On one subnet, all nodes must have same subnet mask,  same Subnet address but unique node address     for example: a) your example shows subnet masks that are not equal - that is wrong b) mask means that first three octets of IP address MUST be same among nodes. PLC 3 is not in there from PLC1 perspective. PLC2 may or may not be detected either,  since mask does not match. it depends how sloppy firmware in that device is c) if you change subnet mask for PLC1 to all three PLCs can talk because all above rules are met      
  25. DeviceNet

    connected how? what PLC? what software? etc