Mitsubishi CC-Link Issue

Hi every one!!!!

Hopefully you all can help my problem..

OK, now i'm working with Mitsubishi CC-Link...In my system there have :

Master CC-Link spec : QJ61BT11
Total Station : 18 Station
Problem station : Station 16 ( I/O range always flicker)
Baud rate using : 5Mbps ( total cable layout within range for this setting)

In my system, CC-Link Master got flicker on it LED L.ERR...
But,remote I/O at station 16 never display ON LED ERR or L.ERR..
Sometime all I/O range in station 16 always flicker due to communication is not good..
When using diagnostic CC-Link function in GX Developer,station 16 sometime OK and sometime error...
Refer to manual, L.Err at master occur due to there have DIP switch setting during power ON..
already try to power off and turn on back, but problem still occur in this system..
i already try to replace remote I/O for station 16 (AJ65SBTB1-32T), condition only good within 1 day, then same problem occur..
What the problem actually? I just can thinking there have 4 step to troubleshoot this problem :
1) Replace I/O card - result NG
2) Replace MAster CC-LInk - still not try
3) Reduce baud rate from 5 to 2.5Mbps -still not try
4) Replace cable - If cable problem, how method to check the CC-Link cable is ok or not ...Help me....

can't you just re-terminate station16? if i recall this unit has removable terminal blocks. i had similar problem when short strand of wire was caught under the terminal. make sure that terminations are neat and clean.

panic mode said:

can't you just re-terminate station16? if i recall this unit has removable terminal blocks. i had similar problem when short strand of wire was caught under the terminal. make sure that terminations are neat and clean.

Click to expand...

Well..already check that condition, everything is good..yesterday, i try reduce the baud rate of speed communication from 5Mbps to 2.5Mbps..the result is good..no L.ERR flicker anymore...diagnostic, condition normal at st 16..but still worry if 2.5Mbps speed will effect with signal send received timing from remote to/from CPU PLC..what do you think? 2.5Mbps is still good for communication speed between remote i/o and CPU?

that depends on your application - what kind of response time would you like? what kind of modules and what are they capable of? manuals should have info on this but in most cases 5ms is more than fast enough which means that one probably wont notice any performance difference even if the speed is reduced another 5 or 10 times.

let's see, if each module uses 32bit and assuming 20 modules that comes to 640 bit. assuming 5ms update interval, bit rate becomes 640/0.005=128000bps or 128kbps. there will be some overhead of course and some of the modules will be capable of about 1ms update time but how fast you really need this to be?

panic mode said:

let's see, if each module uses 32bit and assuming 20 modules that comes to 640 bit. assuming 5ms update interval, bit rate becomes 640/0.005=128000bps or 128kbps. there will be some overhead of course and some of the modules will be capable of about 1ms update time but how fast you really need this to be?

Click to expand...

oic..my system is slat conveyor and integrated with table lifter and telescopic table lifter..ok mr. panic, what i understand with your quote is :

let say my input and output card in manual inform respon time is 2msec ( that mean OFF to On and ON to off).

so let say i have 24 station which is each station using 32 bit

then come to 768 bit, so bit rate become 768/0.002 = 384000 bps or 384kbps.. that mean, if I set 2.5Mbps for my speed communication..i will never face any problem with the response time in my system rite?

correct me i'm wrong...

that's the idea. another question is how fast you really need those signals to be. for example your table lifter is not going to move up/down in 2ms. even if you scan the network much slower (every 100ms for example) you will still see no difference in real life (and this is some 50x slower so your baud rate could be 50x lower or , like 384k/50=7.6k).

the things are different if one of the inputs is registration sensor for example (triggering camera or high speed motion such as robot etc). if you introduce too great delays because of slow network update, your camera may be taking shot after product already moved an inch or so and this may be unacceptable.

this is something you as a designer have to take into account based on your application.

thanx a lot Mr. panic..your info very help for..thank a lot...