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| <== Date ==> | <== Thread ==> |
|---|
| Subject: | RE: Scan problem when the ioc behave as client |
| From: | <[email protected]> |
| To: | <[email protected]>, <[email protected]> |
| Date: | Wed, 16 Mar 2016 11:17:53 +0000 |
|
Hi Tasaddaq, By setting all your SCAN fields to .1 second and all your DTYP fields to stream this means your IOC is attempting to execute the entire protocol 50 times per
second. Since your PLC is only sending 2 packets a second over a serial line running at 9600 baud this is never going to work. The PLC is sending the data unsolicited so you should set SCAN field of the first Input Record to I/O Intr – this will then process every time a packet arrives. This protocol extracts/sends the data from all the other records – so do not set their DTYP fields.
I think you probably need to specify the width as 1 for the %r input converters. Pete From: [email protected] [mailto:[email protected]]
On Behalf Of Tasaddaq Khan Hi Mark The device is sending a stream in 500ms that requests to send the data. But it also send a stream to just update the data of my records in this case it does not require the acknowledge means in response no stream
and during this time it does not send the stream to send the data means interrupt stream to update my records also comes in 500ms. MAIN problem is that I can see the updating stream from my device in my terminal means my protocol file receives the data but it is not updating my records. Secondly, mostly it misses the interrupt stream.
and my database file is : The protocol file is: On Wed, Mar 16, 2016 at 3:02 AM, Mark Rivers <[email protected]> wrote: Hi
Tasaddaq, My suggestion is to obtain the asynTrace output of your drvAsynIPPort driver and the debug output from StreamDevice. var streamDebug 1 asynSetTraceIOMask myIPPort 0 4 asynSetTraceMask myIPPort 0 9 myIPPort is the name you gave to your drvAsynIPPort. 4 means ASYN_TRACEIO_HEX and 9 means ASYN_TRACE_ERROR | ASYN_TRACEIO_DRIVER. That will give you time-stamped messages telling you when you sent and receiving information from the device, and what StreamDevice did with that information. Your original message said you were using SCAN=I/O Intr, but your second message said SCAN=1 second. Please explain how the PLC works: does it ever send “unsolicited” data, i.e. it sends a message without sending it a message requesting data? Or does it only
send a message as a reply when you send it an inquiry message? Please send the complete database and protocol file you are actually using. Mark From: Tasaddaq
Khan [mailto:[email protected]]
Company has provided us the equipment that is not the standard modbus module. It is just calculating the crc of modbus. I have never used the modbus module, is
it possible to suggest me how to improve my above protocol to overcome delay in sending and updating the data of the records. On Wed, Mar 16, 2016 at 12:21 AM, Mark Rivers <[email protected]> wrote: I now see that you are sending a Modbus read request and then reading the response. My question is why are you trying to do this with StreamDevice? Why not use the EPICS Modbus driver that others are using? http://cars.uchicago.edu/software/epics/modbus.html
http://cars.uchicago.edu/software/epics/modbusDoc.html
https://github.com/epics-modules/modbus
It can poll very quickly. The input records can all be I/O Intr scanned and only get processed when the Modbus register changes, etc. Mark From: Tasaddaq
Khan [mailto:[email protected]]
My protocol file is neither updating my record nor receiving the data on time. I miss many packets.My PLC is sending the standard data. e.g. When I update my
record, the stream gets the value after 3 seconds almost. Similarly, I can see the data coming on my terminal means my protocol is receiving the data but my records are not updating so I miss the data. I am facing the same problem with my other stream that has the following protocol file. Secondly, the protocol file does not send the continuous stream sometimes the
DI packet is sent four consecutive times and sometimes DO is sent for three times etc. I feel there is some timing mismatch. All of my records have SCAN time .1 second for above case.
regards, Tasaddaq On Mon, Mar 14, 2016 at 8:06 PM, Mark Rivers <[email protected]> wrote: Is your PLC sending Modbus protocol data, but without a read request, i.e. it is sending unsolicited
Modbus data? If so, that is not valid Modbus protocol. Mark From:
[email protected] [mailto:[email protected]]
On Behalf Of Tasaddaq Khan Hi
My IOC (as client) is communicating with the PLC (as master). PLC is continuously requesting to send data after 500ms with cmd-to-read=0x05 but it can request
to update the data any time with cmd-to-read=0x01 or 0x02 or 0x03, in this case rod-status value is also updated. My Protocol file and records are following: # field(SCAN, "I/O Intr") field(INP, "@ccr-cri.proto data-to-plc(rod-addr,rod-status,) L0") # field(INP, "@ccr-cri.proto data-to-plc L0") } # field(SCAN, "I/O Intr") # field(INP, "@ccr-cri.proto data-to-plc L0") # field(SCAN, "I/O Intr") # field(INP, "@ccr-cri.proto data-to-plc L0") I use different combination to SCAN the records and face following problem: 1. When I use SCAN "I/O Intr" for all the records and all the records(as active), when plc sends one variable then I read 14 bytes at my terminal, but when my plc sends
two variables (like cmd-to-read and rod-addr) then my terminal shows 28 bytes, and when the stream contains all the three variables then I got stream of 42 bytes and ioc stops and message displays (core dump). In this case sometimes my records are updated
and sometimes not. 2. Since my plc is continuously sending data after 500ms, so I adjust the scan rate of all of my records as 500ms. But in this case I got the right stream of 14bytes
and any change in data from the plc I can see on my terminal but none of my record is updating.
3. When I use one of my record active and the other two as passive then sometimes my records are updating and sometimes they miss the data. My records are updated when
my terminal got the 28 bytes. But in this case when I got change in stream my terminal shows the data of multiple of 14. Please suggest me how to handle the situation of PLC (as master) and my IOC (as slave).
Tasaddaq |