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D0-DCM ASCII via Non-Sequence

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  • aphend
    replied
    Originally posted by ControlsGuy View Post
    So if the solution was RTS jumped to CTS on the PC end, why did the same port setup with the same cable work on the other PLC port? That seems odd.
    A valid question. The only thing I can come up with is that there may be enough difference in the input impedance between the onboard, and DCM UART's, so as to cause level changes on the floating RTS/CTS signals. Say that the PC's RTS is floating well above logic one while its CTS is floating barely high. If a difference in signaling power exists between the onboard UART, and the DCM's UART, due to different input impedances, the CTS could slip low and halt communication with one versus the other.

    I was using an ATEN USB to serial converter. It's possible that it was more to blame for radical differences between floating RTS/CTS signals. I should try another model and remove the loop back to see if it makes a difference. I would think that some weak biasing resistors should be employed on these converters to prevent such mishaps.
    Last edited by aphend; 10-30-2015, 07:53 PM.

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  • ControlsGuy
    replied
    So if the solution was RTS jumped to CTS on the PC end, why did the same port setup with the same cable work on the other PLC port? That seems odd.

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  • Do-more PE
    replied
    You are very welcome. I wish I had thought of it yesterday when you called.

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  • aphend
    replied
    Originally posted by Do-more PE View Post
    Try tying the RTX and CTS lines together on the cable. It should be the Dark Green and Dark blue wires.

    Well, I have to say - great idea! Putting a loopback between RTS/CTS on the PC side took care of the issue. I can now read and write ASCII in non-sequence mode. Thank You so much!

    Andrew
    Last edited by aphend; 10-30-2015, 01:18 PM.

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  • Do-more PE
    replied
    Try tying the RTX and CTS lines together on the cable. It should be the Dark Green and Dark blue wires.

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  • aphend
    replied
    I made up my own adapter so I could use an EA-2CBL-1 cable to connect to port 2. Is there anything odd about the pinout of port 2 on the DCM? I simply crossed pins 2 and 3 and grounded pin 7. Again, this cable arrangement works with the PLC's onboard port 2.

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  • aphend
    replied
    Originally posted by franji1 View Post
    Also, make sure you have the right slot number for an 06. If you are used to 205 or 405 slot numbering, the first slot is slot "0". But in an 06, slot 0 is the built-in I/O, hence the first slot in an 06 is slot "1". You might just have an OBOB (what we affectionately call an Off-By-One-Bug).
    Thanks for the reply. I do have the correct slot identified knowing "slot" 0 is the CPU.

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  • aphend
    replied
    Originally posted by Do-more PE View Post
    I am not sure what to tell you. I tried it here yesterday when the tech asked if I knew of anything out of the ordinary that would prevent it from working. It works fine for me using the example as-is from the website.

    The only thing I can think of is that on the Non-sequence setup for the port it asks for a memory address at the bottom of the screen. The default address needs to be changed to one that has 64 words of contiguous free memory available to it. (I just noticed that this is not stated in the manual. I will put in a request to get it changed.)
    Thanks for replying! You say you used the program as-is, but you did change the AIN parameters to use DCM correct? I got the program to work as is off the website too when I was plugged into port 2 of the PLC (CPU).

    I did also read about the large block of contiguous memory required, but not how much, or if any special preparations need to made for this memory. I used V10000 so the module had V10001 to V17777.

    There was also some info I came across about using the slot's special registers for busy and error. I did integrate the special register for COM busy at the AIN rung, without success.
    Last edited by aphend; 10-30-2015, 09:32 AM.

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  • franji1
    replied
    Also, make sure you have the right slot number for an 06. If you are used to 205 or 405 slot numbering, the first slot is slot "0". But in an 06, slot 0 is the built-in I/O, hence the first slot in an 06 is slot "1". You might just have an OBOB (what we affectionately call an Off-By-One-Bug).

    Leave a comment:


  • Do-more PE
    replied
    I am not sure what to tell you. I tried it here yesterday when the tech asked if I knew of anything out of the ordinary that would prevent it from working. It works fine for me using the example as-is from the website.

    The only thing I can think of is that on the Non-sequence setup for the port it asks for a memory address at the bottom of the screen. The default address needs to be changed to one that has 64 words of contiguous free memory available to it. (I just noticed that this is not stated in the manual. I will put in a request to get it changed.)

    Leave a comment:


  • aphend
    replied
    As a work around, I setup the D0-DCM for K-Sequence and used it for my HMI which worked fine, so I know the DCM is operational. Doing so allows me to use the PLC's onboard port 2 for Non-Sequence ASCII, which also works fine.

    FRUSTRATING!
    Last edited by aphend; 10-30-2015, 06:58 AM.

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  • aphend
    started a topic D0-DCM ASCII via Non-Sequence

    D0-DCM ASCII via Non-Sequence

    I have been unsuccessfully trying to communicate non-sequence ASCII strings via RS-232 from a D0-DCM communication module in a DL-06. My PLC firmware is at 2.6 and the D0-DCM firmware is at 1.2. I am running DirectSoft 5.3. I can see that the option card is found under PLC->Configure IO, and I can set it up properly in PLC-Setup->D0-DCM. When I power up the PLC, the Tx/Rx LED's for each port on the D0-DCM, all light up briefly.

    The small example program I am running simply issues an AIN command and shifts the data into a waiting V memory location when complete. This program WILL work fine with the CPU's onboard port 2 but will NOT work with the DCM port 2. When using the DCM's port 2, the AIN command remains in the busy state and never fires its complete signal. Another interesting observation is that the port 2 Rx LED on the DCM never flickers when sending the ASCII strings.

    The AIN command is configure to look for a carriage return (0D Hex) on a variable length string. I have also tried fixed length strings and they do not work. During setup, I've made sure the D0-DCM's slot ID is correct and that the V memory locations are accessible. The COM port setup is also identical to how I setup the working CPU's port 2. I have also tried shifting the DCM to all slot locations.

    I'm using HyperTerminal to send the test ASCII strings. Again, this works for the onboard port 2 using the same cable.

    Here is a link to the example program I am working with...
    Program EP-COM-008 from http://support.automationdirect.com/examples.html#com

    Any insight would be greatly appreciated
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