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Old April 11th, 2006, 01:24 PM   #1
DL06
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C-More - Timeout Setting

I have three Automation Direct C-more panels communicating with a DL06-DD1 with a 10/100 Ethernet module. I notice that on the top of the screen I am getting a PLC timeout error (or sometimes a NAK)

Everything is hooked up correctly and information is being transmitted to and from the panel perfectly. I do notice that the timers update every 1/2 second or so and seem a little laggy. Is there perhaps a setting that causes the error message to be displayed if the time between communications is greater than xxx milliseconds? Is this a PLC or a HMI setting that I should be looking for? Is there a way to make the displays a bit more responsive to inputting and outputting data (i.e. reduce the lag)

If anyone has come across this and can help me out, I'd appreciate hearing what you have to say.

Thanks in advance.
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Old April 11th, 2006, 03:19 PM   #2
glaverty
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Well I haven't used these things with a DL-06 but you can change the time out parameters under the Panel - Panel Manager Menu, you must have completely missed them when you setup the IP Address.

Also the fact that you have three panels talking to one PLC might slow things down a bit.
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Old April 11th, 2006, 04:36 PM   #3
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You can setup both the timeout value and the poll time value for each link. I've found a fairly quick poll time of about 5 with a timeout of about 25 and 2 retries works pretty well with multiple PLCs and a lot of network traffic. Keep in mind that there is only 100Mbps available on the network and while that may sound like a lot of bandwidth (and it is) that everything still must take turns and no two devices can talk at the same exact time.

Also what C-More panels are you using?
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Old April 14th, 2008, 01:40 PM   #4
plc noob
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mark

i have a very similar setup but 4 plc's . i have changeed the poll time and timeout to your settings . just to clarify when you increase the poll time does that slow down how often the panel checks the plc i/o status or does it speed it up . poll time is zero by default ?
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Old April 14th, 2008, 01:55 PM   #5
marksji
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Poll time is how long the panel waits between communications with the plc. A setting of 0 means that the C-More does all its reads/writes then immediatly does them all again. A setting of 5 means that the C-More does all its reads/writes, then waits 5ms, then does all its reads/writes, then waits 5ms ...

Timeout is how long the C-More waits to receive an ACK from the PLC before giving up on the last packet and either resending (retry) or displaying comm error.
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Old April 14th, 2008, 02:11 PM   #6
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Thank you for that explaining that mark. That was my mode of thinking but I wanted to be sure. Thank you for your help
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Old April 15th, 2008, 09:58 AM   #7
icky812
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It seems counter intuitive, but increasing the poll delay can actually speed up communications.

If the HMI (or other commmunications device) is constantly being hammered on, then some of the packets are getting rejected or having to wait for free processor time to deal with them. By adding a small amount of delay you give those packets time to be processed, speeding up the throughput.
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Old September 10th, 2008, 09:54 AM   #8
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Angry C-more comm errors

I've got a single SLC 5/04 connected to a C-more EA7-T8C. It is being used primarily for status display (output only). There are settings in the PLC that can be changed via a password-protected series of screens on the C-more. At this time, I am the only person with access to them. There is no handshaking being used, yet about every-other day, the screen is frozen with the following 4 messages cycling in a one-line gray banner at the top of the screen:

Nak received from PLC
ENQ received from PLC
PLC Communication Timeout
Transaction ID does not match

Neither re-booting the screen, nor toggling the PLC from RUN to PROG and back to RUN clear the symptoms. The only way I seem to be able to get the screen functioning again is to power down the PLC and re-start it.

I never had this problem during development. Both the panel and the PLC are the same ones used at that time. If I run the C-more's built-in PLC Enquiry test, it runs 4 times, passing each time.

Any help would be appreciated.

Jeff
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Old September 10th, 2008, 12:48 PM   #9
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Which protocol are you using? DF1 Full duplex, DF1 Half duplex, DH485?

What version of C-more firmware?

When this error occurs, can you unplug C-more, plug in your PC and communicate to the PLC with RS Linx?

What does 'frozen' mean? Screen doesn't react to touch? It doesn't seem frozen to me if errors are changing on the screen.

What kind of devices are in proximity to the C-more panel and PLC?
How are you powering the panel and PLC? What else is powered on the supply to the panel and PLC?

Lots more information is needed for us to be able to give any help.
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Old September 10th, 2008, 01:28 PM   #10
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There is always more information that can be given. Initially, I was just "fishing" to see if anyone else was having (or had seen) similar problems and/or messages.


To answer your questions:

I'm using DF1 Full Duplex at 9600 baud, no parity, 1 stop bit, no handshake, BCC error detection. ACK Timeout set to 200 (x20 ms = 4000 ms = 4 seconds), NAK Retries and ENQ Retries both set to 3.

The C-more has the following version information:
Hardware: 1400
Boot Loader: 2000
Firmware
OS: November 15 2005 at 12:02:22
Runtime: 1.1.1.3A
System Screen: 1.1.1.3A

The C-more memory information is as follows:
Total Usage Free
SRAM 256KB 3KB 253KB
Flash 48MB 8MB 40MB

I haven't yet tried communication with RSLinx via the DB-9 port (Channel 0) when this problem occurs. RSLinx communications do NOT fail on Channel 1. The PLC program continues to run normally.

The screen doesn't update, and the solitary button that takes you to the program settings page does not respond. So, by "frozen" I mean that the C-more software (my program) is frozen, not the C-more firmware.

There is an ABB Kent-Taylor Commander 200 process controller mounted within 6 inches (the same controller used on the bench during development, at about the same distance).

Power is fed to the control panel via a dedicated 20A circuit. From there it feeds separate circuit breakers for: 1) control circuitry, 2) SLC, and 3) C-more.

Development was done on a non-dedicated (rather dirty) circuit with many other devices, computers, and lights being run at the same time.

Last edited by zgozvrm; September 10th, 2008 at 01:32 PM. Reason: Formatting/typos
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Old September 10th, 2008, 01:34 PM   #11
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Wow, that's pretty old firmware.
I went to AD's website and looked at the firmware history and that version appears to be right after the product was released.

I would seriously consider upgrading. There have been quite a few fixes since then.

It would be what I would do if I were in your shoes.
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Old September 10th, 2008, 03:46 PM   #12
Tharon
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Quote:
Originally Posted by zgozvrm
Nak received from PLC
ENQ received from PLC
PLC Communication Timeout
Transaction ID does not match
I had some very similar errors appear on my C-more that is connected via DF1 to a Micrologix 1200.

My problem was due to some nasty math errors I had in my program that the C-more did not like. I had to power down the machine to clear the errors, and once I fixed my math problems in the PLC, the errors never happened again.
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Old September 10th, 2008, 05:35 PM   #13
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Any chance you can recall what the "nasty math errors" were? And, did you have any PLC faults (major or minor)?
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Old September 10th, 2008, 05:46 PM   #14
Tharon
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Quote:
Originally Posted by zgozvrm
Any chance you can recall what the "nasty math errors" were? And, did you have any PLC faults (major or minor)?
It was quite a while ago.

I had a 0-10Vdc analog input, and was using the Scale w/ Parameters command. I had my input device fail, and my Cmore was used for calibrating it. (Min and Max input, and then to a set value somewhere in between).

It was like... division by 0, etc. I guess the SCP function doesn't like it when Min and Max are the same value.

I do believe it faulted out the processor. But the Cmore did not like one or more of the float values that where coming from that and had locked up. It was so long ago that I cannot remember which firmware I was running at the time.

Since that time, I've removed all Float values from the Cmore panels. Instead I just multiply them by 1000 and move them into an INT file for the Cmore to read, then I use the Cmore's program to put the decimal point back into the correct location. This way it also eliminated the very small near 0 values reading as 1E-15 and the like.
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Old September 10th, 2008, 06:10 PM   #15
zgozvrm
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Quote:
Originally Posted by Tharon
It was quite a while ago.

I had a 0-10Vdc analog input, and was using the Scale w/ Parameters command. I had my input device fail, and my Cmore was used for calibrating it. (Min and Max input, and then to a set value somewhere in between).

It was like... division by 0, etc. I guess the SCP function doesn't like it when Min and Max are the same value.

I do believe it faulted out the processor. But the Cmore did not like one or more of the float values that where coming from that and had locked up. It was so long ago that I cannot remember which firmware I was running at the time.

Since that time, I've removed all Float values from the Cmore panels. Instead I just multiply them by 1000 and move them into an INT file for the Cmore to read, then I use the Cmore's program to put the decimal point back into the correct location. This way it also eliminated the very small near 0 values reading as 1E-15 and the like.
Tharon,

Interesting! My program is using several SCP commands as well. And, I'm using the C-more to calibrate them. As stated before, the screens where system settings like these are located are password-protected so that curious fingers don't get themselves in trouble.

I do have an issue with a flow meter that's set up for 4-20mA in the 0-400 gpm range. Occasionally, I'll see values on the flow meter's display that don't make sense, like "-1219 gpm." But, the actual output of the meter is limited to the 4-20mA range so that anything less than, or equal to 0 gives me a 4mA signal. My values are already limited to integers (no floating point numbers are even used in the PLC).

I don't see how that could (or should) affect the C-more, but I'll look into it a bit more. We may be on to something!

BTW, I just upgraded my firmware from 1.1.1.3 to 2.20 (the newest available on AD's website).

Thanks,
Jeff
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