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Posts posted by Thermo

  1. Another factor that might be affecting the speed of response are the settings in the AC VSD.  For example it may have rate-of-change (or slew rate) settings that prevent the output frequency changing as quickly as the speed setpoint from your PLC.

    But as Dick has said above, the ability of your proposed system to work properly will depend ultimately on the characteristics of your process.  Centrifugal pumps have a very non-linear speed/flow/pressure relationship.  Can you post a P&I Diagram or sketch to explain what you are trying to achieve?


  2. Thanks GT.    I seem to have everything working well now and I've created a small program to add some 'smarts' to 1980s vintage sun-tracking solar hot water heater I acquired years ago.

    Thanks again for your help and offer of future assistance.


  3. Hi Bob & Mr Mode (or may I call you Panic?),

    It's horses for courses, of course:-1.  DCS evolved for process control, PLC evolved for machine control.

    While I had a little to do with Honeywell TDC2000 (yes, 2000) and quite a bit with Bailey Network 90 in the late '80s.  But most of my experience had been with Yokogawa DCS since the early '90s.  A big thing about the Yoko systems is that they are absolutely deterministic.  The proprietary comms bus had a 1 sec scan time no matter how many operator stations and controller nests were installed, up to the specified maximum (and even in the 'little' uXL system that could be a massive I/O count (100,000 tags from memory?)).  The standard controller scan time was 1 sec - rock solid, no variation - which is more than enough for 99% of analog control and non-machine digital control (motor control etc.).  Fast scan for a limited amount of the program was 200ms (stop laughing, this is serious!).  But this is good enough for compressor surge control.  The newer successors (Centum CS, CS3000, VP) offer scan  times for limited  areas down to 50 ms - but again rock solid guaranteed. 

    I ran training on uXL for a while.  Sparkies/engineers with PLC backgrounds invariable scoff and laughed when the scan times came up but were generally impressed by the end of the training by the deterministic nature of the system and the simplicity of the total and tightl integration of the system.  Define a single DIO point or a PID control block and you automatically have a fully-featured faceplate for your HMI that is updated every second.

    But, as I said, 'horses for courses'.  Ian

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  4. Hi Bob,

    Yes, I'm a happy little Vegemite now.

    1 hour ago, BobB said:

    Also an issue with the latest PLCs if you want to insert FBs - have to stop the PLC - I use very few FBs because of that.

    Gees, that would be annoying.  I know this is no place to re-start the old PLC Vs DCS discussion (for one thing, I'd be outnumbered about 1,000,000 to 1!) but clunky as it was, the old Yokogawa uXL (read: micro-XL, the little brother to Centum XL, late '80s to late '90s vintage) and it's successors, were brilliant in that regard.  Very little you couldn't do on-line/hot.  

    Changing analog signal conditioner cards, AIO and DIO cards and even processor cards in dual-redundant systems could all be done hot and on-line (with due regard to the effects on the process during changeover, of course).  And analog control blocks and sequence tables could be added/edited on-line.  [Sequence Table: think of a block of up to 32 rungs of ladder with up to 32 contacts and 32 coils per rung.  Packs a lot of logic into a small space.]

    Ah, enough reminiscing for now...

  5. On 3/11/2016 at 0:31 AM, Crossbow said:

    Depending on what you are trying to do, you may not need a PLC at all.  The Omron Zen is a small programmable controller with relay outputs.  You could use it to do some of the things PLCs do, like timers and counters and logic.  Just not much use for things like math and analog control.

    I have used CPM1A before, and it's a good little PLC.  But I also used an official Omron cable, so I had no trouble getting online with it.  I recommended before that you get a CPM1-CIF01 and make a serial cable, or get the CQM1-CIF02.  If you need to use a USB to serial adapter, I always had great sucess with many vendor's PLCs using the Keyspan USA-19HS USB to serial adapter.  Some of the others out there (and the generic cables) are just crap.

    Thanks for the Zen suggestion, Mr Crossbow.  I've just read the brochure and I'm sure it would eat my simple application for breakfast.  Shame the turkey at Omron Aust didn't bother to mention it as an alternative to his $1000+ suggestion - I would have been interested.  I'm now happy I can play around with my CPM1A for the time being but I'll keep the Zen in mind should I need to do a simple 'real' project in future.  Ian

  6. Hi pfort,

    It's all good now - was my misunderstanding.  I wanted to clear the memory settings and old program so I knew exactly the state of the PLC before downloading my program.  I used the function shown below.

    Now since I used this function, I've successfully downloaded my  program and uploaded it again to check it, and run monitoring mode etc. and all seems to be working perfectly.  However, since doing the memory clear, the comms LED and the USB adapter TX/RX  LED have been flickering constantly.  I mistook this for the 'memory clear' process taking forever, but it seems to be 'normal' for my set-up.  Does this sound right?

    In any case, thank you for your help.


    Screen image 1.jpg

  7. Hi GT, Bob and Jay,

    Many thanks for your contributions and help today and previously.  Hope you all enjoyed your stroll down memory lane.  In a parallel world I could mention the 'in-cabinet' monitoring module in the Toshiba Tosdic DCS in the early '80s and the wonderful 'fill-in-the-forms' configuration system of the Yokogawa uXL DCS.  Similarly clunky and crude by today;s standards to your old PLC programmers/software, I would think.  And showing my age too now...

    Jay, thanks for the old tech note.  However, even after finding an early '60s Toyota Owner's Manual to help interpret it, I still couldn't make much sense of it!

  8. Hi Crossbow & Bob,

    Thank you both for your suggestions and help.  However, it seems Gtsuport's suggestion to try the Trail version of CX-One has paid off.  If only this endless Clear All Memory process will end - or have I created another monster...


    PS: Please disregard comments about "endless Clear All Memory process".  It worked correctly and I've since downloaded and monitored my program.  It's just that the comms LED and the USB adapter LED's now flicker continuously.  But everything seems to be working, so I'm not complaining.  Ian

  9. 8 hours ago, BobB said:

    I am not sure if auto online works with the CPM1A or not - trying to find one to try it. He can post it too me and I will try it for him. We are in touch by PM. I do have some doubts about the Chinese cable but it may be OK.

    Hi Bob,

    As per my reply above to Gtsuport, it seems your idea of trying Auto Onlne worked - and after much effort to get CX-One Trail working, it did indeed reveal my PLC's comms setup.

    Thanks very much for your help to date and your generous offer to try to communicate with my obsolete plastic brick for me.


    PS: The Chinses USB cable/adapter seems to be working OK - but this Clear All Memory seems to be taking an awful long time.  Does it have to write a '0' individually to even bit in memory?

  10. 17 hours ago, gtsuport said:


    I know I am joining this thread late in the game, but had a thought.

    You should be able to download the trial version of CX-One.  This is a large file, and it would only work for 30 days.  However, there is an Auto Online function in that software that should be able to sort out the comm parameters for your CPM1A. 

    Once you have those parameters, you should be able to enter that information into Syswin and hopefully connect.

    If you are unable to locate a download link for the CX-One Trial, let us know and we can provide a link.

    Hope this will help.


    You are not only incredibly handsome and charming but you are also a genius!!  What a brilliant idea (although this does not at all diminish BobB's generous offer to try my 'brick' with his Auto Online function...).

    It's taken all of my Saturday and half my monthly data allowance but I finally managed to download CX-One Trial and install it.  (Being is such a remote outback location (i.e. less than 2 hours from the state capital, Brisbane), we have third world or lesser internet access here...)

    Once I finally got it all working, Auto Online did indeed 'find' my CPM1A's comms settings - 19200 baud, 1, 7, 2, even.  The suspect Chinese USB adapter/cable preformed faultlessly.  I was able to upload the old PLC program etc.

    Then switched over to Win xp mode and Syswin, plugged in the appropriate comms settings, and Hey Presto! - it worked!  Many thanks to all who contributed.

    The current state of play is that I selected Online/Clear memory/All Areas/OK - and it's still going.  How long should this take?

    Thanks again all,


  11. Hi all,

    Some of you may have read my earlier saga of, on impulse, buying an obsolete Omron CPM1A + expansion unit and the subsequent trials and tribulations of obtaining suitable software and cable to talk to it.

    It's looking increasingly like my Omron-branded oversize Lego block will remain an interesting paperweight. So, given that I have a small 'home' project that I'd like to implement and have written a plausible program in Syswin for the CPM1A, what are your suggestions for a way to go if the CPM1A remains 'incommunicardo'?

    Automation direct have their CLICK 8/6 I/O micro PLC and cable for a low cost with, supposedly, free software.  This should have all the smarts I need for my simple program.  Any other suggestions?  Please bear in mind, this is for a home-brew project and self-training, so obvioculy I won't be spending $mega on 'all singing, all dancing' software like CX-One.

    Thanks all,

  12. Hi all,

    I'm fairly new here, as I've not had a lot to do with PLCs.  However, I have several decades experience with Yokogawa Distributed Control Systems (DCS), including uXL and Centum XL, CS, CS3000 and VP.

    So, should anyone be looking at replacing an aging Yokogawa DCS and need assistance decoding/reverse engineering the system configuration, please send me a PM and we can discuss.


  13. Hi All,

    Thanks to all who helped with my first post - how to get started with a second-hand CPM1A PLC.  Thought I should now start a more specific thread.

    I now have Syswin 3.4 running in Windows xp mode in Windows Virtual PC, I think I have a Chinese USB-CIF02 comms cable/adapter and drivers correctly installed in Win xp mode.  The PLC powers up with the PWR and RUN LEDs lit.  The USB adapter TX LED flickers when I use the Syswin comms test function, indicating that Syswin is talking to the adapter.  But having tried 128 combinations of comms protocol and unit address at 9600 baud without success, I believe there are now two possibilities.

    First, while Syswin is sending something to the USB adapter, it may not be 'talking' correctly to the PLC .OR. the PLC is set for some unusual communications settings for reasons unknown, that I may never be able to stumble upon.  Both possibilities could be eliminated if I could return the PLC to the factory default state, with a known comms setup.

    However, it seems the comms settings in DM words are stored in Flash memory and can only be changed if I can 'talk' to the PLC - Catch 22?  I can find no sign of any DIP switches or hardware reset button etc.  Surely there must be some way to clear the flash memory to return the device to the factory default state?  All suggestions gratefully received.


  14. Hi Bob,

    The device is all one piece.  USB plug one end, small black box in the middle with TX/TX LEDs and a 20-pin plug that connects to the PLC port on the other end.  Photo below.  Seems quite well made and the AMSAMOTION website, while very difficult to read, seems to list lots of different PLC comms cables etc.  Do those driver names above mean anything to those who speak fluent 'Omron'?

    PS:  Seems I've been promoted to the rank of 'Sparky'.  That development will be quite worrying to most of the real sparkies I know!

    USB -CIF02.jpg

  15. Sorry Bob.  Forgot to mention this morning - there's no sign of any DIP switches on my CPM1A PLC (unless you have to open the case to access them?).  Any other ideas on how to return this thing to the factory defaults settings?  Anyone?



  16. Hi again Bob and others,

    Thank you for your patience and ongoing support to me here at "Obsolete Automation Inc."  Regarding the unit number, yes I did misread the manual.  I read the 'CV" section on unit numbers rather than the 'C' series section (image attached).  I have however been reading manuals assiduously and learning lots along the way .

    Yesterday I spent about an hour trying the SYSWIN Project|Communication "Test PLC" function with the four 'standard' protocols (ASCII 7 bit even/odd parity & JIS 8 bit even/odd parity, all at 9600 baud) with every unit address form 00 to 31 - to no avail.

    I presume what I have on my CPM1A is a "Direct CPU Peripheral Port", as highlighted on the attached image?  So therefore my host comms settings and unit number are set in DM settings?  In particular, DM6650 to 6653 incl.?  

    My reading of the hardware manual shows that "The user program and memory area data in the CPU Unit are backed up by either one of the following methods.  Flash Memory:  User program, read-only DM area (DM 6144 to DM 6599), and PC Setup area (DM 6600 to DM 6655).  Internal Capacitor: DM areas other than the above, HR area, AR area, and
    Counter area."  

    So, my host comms settings are still held in Flash Memory, no matter how long the unit has been powered down?  And if my settings are some strange combination of uncommon settings I may never be able to communicate with it?

    If all this is correct, is there a way (like some secret Omron handshake etc?) to clear to flash memory to all zeros, so that the default settings are restored, i.e. "00: Standard (1 start bit, 7-bit data, even parity, 2 stop bits, 9,600 bps)", and Unit no. 00.  If I've got this all wrong, my apologies for wasting your time.

    Regarding my USB adapter cable, I'm sure it's on COM3 as that is the only port selection that results in the TX LED flickering when I do a comms test.  The adapter driver details are attached.  Do these driver names mean anything to anyone outside China?  Or am I flogging a dead horse with this cable?

    C & CV Units Numbers.pdf



    C & CV Units Numbers.pdf

  17. Hi again Bob & others,

    OK, I now realize I have purchased a long obsolete PLC that was basically worthless and I'm pushing 'possibility' up hill trying to get it to work.  (But hey, you see these things on eBay and think, "I've always wanted to have a play with one of these" and the rest, as they say...

    But I've had a bit of a win (but only a bit, mind you).  It seems the AMSAMOTION UBS adapter installed itself as a generic USB 2.0 device.  So I tried to attach to it in Win XP mode under Virtual PC, only to have it fail repeatedly, along with all other USB devices on the host Win 7 machine.  Much Googling later and I found a thread suggesting going into the BIOS and disabling USB 3.0 functionality.  After doing this and restarting both the host machine and Win XP mode, the generic USB 2.0 deviuce not only let me 'attach' to it but prompted me to insert the CD disc and proceeded to (presumably) install itself correctly.  Yoo-Hoo!

    So I can now attempt to connect to the CPM1A via this cable/software.  The adapter TX LEDs flickers promisingly when I try the SYSWIN Project|Communication "Test PLC" function.  But it responds with "Connect failed" or "No response from the PLC".  I believe the 'shoe-box' PLCs are always Unit 00?  And I'm pretty sure the adapter is on COM3 of the Virtual PC.  So can anyone help with some protocol settings I could try to get my PLC to talk, please?  Or any other things to try?  Is there a way to get the PLC to revert to some default protocol settings that I could then try in SYSWIN?

  18. OK, I was warned!  Received my AMSAMOTION USB-CIF02 "USB to RS232 adapter for Omron PLC CPM1A..." yesterday.  And it doesn't seem to want to install on my Win 7 laptop - surprise, surprise!

    I realize this is not the sort of device professionals would even waste their time on but , as mentioned, I'm just a tinkerer wanting to play around with a second-hand PLC without spending loads of money.  The cable came with a mini-CD that seems to have lots of drivers on it but there is a lot of Chinese language in the file and folder names that may be upsetting my laptop that doesn't speak Chinese (as far as I know).  May I ask if anyone reading this has managed to get this device working satisfactorily?

    Bob, I'm loath to purchase anything from Omron Australia/Asia Pacific.  After numerous attempts to contact them, trying to purchase legal software and cables for my CPM1A, I finally received a phone call (I believe triggered by me requesting CX-Programmer from the Omron Europe website!).  This guy didn't want to know about someone with an obsolete PLC.  He insisted CX-Programmer can't be purchased separately from CX-One (Although Omron Europe still list it separately).  All he could offer me was a 'deal' to buy a new CP1E plus CX-One Lite for over A$1000.  Tinkerers need not apply...

    I have now written my first program - a whole 5 networks but with three timers, a MUL function and using the two Analog Value 'pots' on the front panel.  I'm quite proud of it but until I can sort out my cable issue, we may never know if it works.

  19. On 2/16/2016 at 11:35 AM, pfort said:


    Syswin can work on Windows 7 64 bits.  (Windows virtual PC in Accessories menu)

    Hi pfort and Crossbow,

    Thanks for your help gentlemen.  I now have my PLC, and a Chinese USB-to-CPM1A cable and driver disk is winging its way from Hong Kong (fingers crossed).  The PLC and expansion unit arrived with most of the wiring loom from the cabinet it came out of,  most with 4 digit Graphoplast wire numbers attached.  So, I have lots of hook-up wire and wire numbers to use in my home-brewed project!

    I also have a Windows XP virtual machine up and running under Windows Virtual PC (thanks pfort) and Syswin 3.4 installed and apparently fully functional.  It seems to have all the help files and allows me to define and save a Project anyway - that's all I've tried yet.  So far, so good.

    Now to start my first PLC program...

    Thanks again.


  20. Hi Crossbow,

    Thank again.  I certainly would like to buy legit software and cables if possible and not prohibitively expensive, but I have sent two website enquiries and two emails to Omron Asia Pacific now and have yet to receive any reply at all.  (If anyone reading this has contacts with Omron AP, please put a rocket under them!  This is not a good way to encourage someone trying to learn to use their products...)

    I managed to purchase a used CPM1A-30CDT-D and 20 EDT (CP1A) Expansion I/O Unit for AUD89.00 delivered.  Unfortunately, until I can find some suitable software and cable, it will remain an interesting paper weight.