ioscanner loss of communication

[jagg 0]

have setup ioscanner between 2 plc's with noe cards for communication. have had problem with 1 of the bits not being updated it seems to me, this is a bit that should stay on all the time as a permissive for system to run. the others are on only when required by system when running ei: home position or extend position ..... now on thhe unity installed plc under the communications tab under noe i have setup the transfer of info to other plc. the one thing iam looking at is this has a "device control block" i have not set this up as i dont think this is needed ? maybe iam way off here any ideas? maybe i missed something quite basic and general to the setup of the ioscanner. the original setup using hardwire between the plc's works fine but when i switch to ioscanner and disable the hardwire setup is when i see the problem. thanks for any help

[Crossbow 295]

IO Scanner function is typically for remote I/O devices, like Momentum I/O blocks with Ethernet comm adapters, you should use the Modbus read/write commands in the PLC to communicate between two processors. At least that's how it was 8 years ago when i last touched a Modicon PLC.

[aggattapauer 2]

I/O scanning is a service exactly the same of read/write commands. There's no difference except for the function code 23 used to read and write at the same time. You could use I/O scanning service anytime you need to communicate with any modbus devices (not only with very OLD momentum). First, are you talking about Quantum or M340? Untiy or previous PLCs? Second, could you post exactly your configuration? the control block is not necessary, you're right.

[jagg 0]

hello thanks for the replys yea i have quantum setup the 651 50 has unity v4 and the other quantum setup is with proworx32 model ummm i forget it but is 1 of the older ones a 234 think. the setup isis using 2 noe cards 77101 these are setup in its own run of network cable now i have setup the discreets in proworx to a 4xxxx reg. this is to be read by the unity setup now the variables in unity have been declared and used with a "bit to word" then a "word to int" blocks which is to be read by the proworx setup. have setup the ioscan in both plcs and things seem to work for a while but then it seems i lose communication on the 1 bit that should be always on, it then causes the machine to lose auto we then reset and restart machine and things are fine again. when i run with the original hardwire setup ioscan disabled it runs good no problems. i do have the proworx "read count" set at 100 which i intend to set to 1 when iam able to do a start/stop of plc, the "read lenght" in unity is set to 1. the "health timeout" is 1500 in both plcs, the repititive rate iam unsure what i set those to right now but it will be around 20 is this a value which should be the same in both setups? the "last value" is set to fallback to zero in both setups. ok think i have most of it stated here anything else please let me know. wandering if scan time difference between the 2 plcs has something to do with it being that the unity setup should have a much lower scan time is the proworx setup with its higher scan time causing a error?

[aggattapauer 2]

do you need to exchange only 1 word?? ok, first you don't need to setup io scanning in both plc's. Choose the one you want to be the "master". I suppose the Quantum Unity. I suppose you want to read from Proworx the address 41000 and store it in %MW2000. I don't understand if also Proworx has to read a word from Unity... so I suppose yes and it's mean Unity has to write its %MW2100 to Proworx 41100. Now you have to setup in Unity noe two io scanning line: one for reading; one for writing. time out 1500 is enough the repetitive rate must set greater than the maximum scan cycle so 20 (milliseconds) could be critical. This setting is needed to configure how many milliseconds the io scanning has to wait before sending every new command. reading register start from 2000 (%mw2000) the address to be read is 1000 the length 1 the write section must be 0 the second line is to be set the same as above but for writing section writing register starting from 2100 (%mw2100) read address and length must be 0 the address to be write is 1100 the length 1 Now when write 1 in 41000 you'll have 1 in %mw2000 and by writing 1 in %mw2100 you'll find 1 in 41100. Tell me what are exactly all configuration you did with correct addresses. Good job!

[jagg 0]

hello yes only doing 1 word each way sup. wants only reads done so each plc does a read of the other. ok i verified few things today unity cpu=65150 noe=771-11 f.w=4.3 ipaddress=proworx noe ip address unit id=255 health timeout=1500ms repetitive rate=16ms rd master object=%mw150 rd slave index= 4499 (which is offset for the proworx plc reg.=404500) rd lenght=1 last value(input)=set to zero proworxnxt cpu=213-04 noe=771-00 f.w=4.3 ip address=unity noe card ip address unit id=255 health timeout=1500ms repetitive rate=20ms function =read fallback value=zero read ref. local=404505 read ref. remote=400155 (which is %mw155 address in unity ) read count=100 (when able will lower to 2) i did a check on scan times unity=29.9ms proworx=49.9ms think that it for now i have a ntron switch beteewn the plcs and will be changing that out when able

[aggattapauer 2]

ok up to you, in that case I would prefer to perform only one IOscanning (read and write) so I won't run into synchronization problems. As I understand you have to manage something like a sequence..