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<== Date ==> <== Thread ==>

Subject: RE: Proposed support for additional Modbus data types
From: Mark Rivers <rivers@cars.uchicago.edu>
To: "'haquin'" <haquin@ganil.fr>, Eric Norum <wenorum@lbl.gov>
Cc: tech-talk <tech-talk@aps.anl.gov>
Date: Fri, 6 Apr 2012 20:14:10 +0000
Hi,

I was able to reproduce the problem with SCAN=I/O Intr on asynInt32 arrays crashing.  I have found and fixed the problem.

Here is the patch:

corvette:modbus/modbusApp/src>svn diff -r14638:14653 drvModbusAsyn.c 
Index: drvModbusAsyn.c
===================================================================
--- drvModbusAsyn.c     (revision 14638)
+++ drvModbusAsyn.c     (revision 14653)
@@ -1371,8 +1371,9 @@
                     break;
                 }
                 /* Need to copy data to epicsInt32 buffer for callback */
+                pasynManager->getAddr(pInt32Array->pasynUser, &offset);
                 for (i=0; i<pPlc->modbusLength; i++) {
-                    status = readPlcInt(pPlc, offset, &int32Data[i]);
+                    status = readPlcInt(pPlc, offset+i, &int32Data[i]);
                 }
                 asynPrint(pPlc->pasynUserTrace, ASYN_TRACE_FLOW,
                           "%s::readPoller, calling client %p"


I am unable to reproduce the problem with writing FLOAT32_LE values.  I can write them to the Modbus slave simulator and display the correct floating point value.

These are the lines from my test startup script:

# Word access at Modbus address 0
# Access 60 words as inputs.  
# Function code=3
# default data type unsigned integer.
# drvModbusAsynConfigure("portName", "tcpPortName", slaveAddress, modbusFunction, modbusStartAddress, modbusLength, dataType, pollMsec, "plcType")
drvModbusAsynConfigure("A0_In_Word", "sim1", 0, 4, 0, 60, 0, 2000, "Simulator")

# Access 60 words as outputs.  
# Either function code=6 (single register) or 16 (multiple registers) can be used, but 16
# is better because it is "atomic" when writing values longer than 16-bits.
# Default data type unsigned integer.
# drvModbusAsynConfigure("portName", "tcpPortName", slaveAddress, modbusFunction, modbusStartAddress, modbusLength, dataType, pollMsec, "plcType")
drvModbusAsynConfigure("A0_Out_Word", "sim1", 0, 16, 100, 10, 7, 1, "Simulator")


These are the lines from the substitutions file:

# These are the A0 inputs done with word access
file "../../db/intarray_in.template" { pattern
{P,           R,                PORT,     OFFSET,   DATA_TYPE,  NELM,    SCAN}
{SIM1:,    LI:UINT16,        A0_In_Word,     0,     UINT16,       46,   "I/O Intr"}
}

file "../../db/aoFloat64.template" { pattern
{P,           R,               PORT,      OFFSET,   DATA_TYPE,    LOPR, HOPR, PREC}
{SIM1:,    AO:FLOAT32_LE,    A0_Out_Word,    6,     FLOAT32_LE,   -1e6,  1e6,    3}
}


I have created a new beta release, R2-4beta2.  You can get it here via Subversion:

https://subversion.xor.aps.anl.gov/synApps/modbus/tags/R2-4beta2/


Or here via a tar file:

http://cars.uchicago.edu/software/pub/modbusR2-4beta2.tgz


Please let me know if it fixes your crashing problem.

Also, please tell me the actual error with your FLOAT32_LE ao record problem.  Are you sure that Modbus offset 5 is correct.  That is an odd number, and I would expect the 32-bit floating point registers might be located at even 16-bit word offsets, i.e. either 4 or 6, not 5.  Remember, when you specify the offset of the 32-bit floating point value you specify it in units of 16-bit Modbus registers, not in units of 32-bit registers.

Cheers,
Mark



-----Original Message-----
From: haquin [mailto:haquin@ganil.fr] 
Sent: Friday, April 06, 2012 9:47 AM
To: Eric Norum
Cc: tech-talk; Mark Rivers
Subject: Re: Proposed support for additional Modbus data types

Hi,

- I don't understand why the Linux IOC crash is not reproducible ...
so now the behaviour is the same on both Linux and VxWorks:
Data in the waveform are equal to zero if scan is I/O Intr
Data are correct in the waveform if scan is periodic

- I've successfully tested the read INT32_LE function.

I don't manage to write a FLOAT32_LE:

here is my record:
record(ao, "$(EQPT):TstICons") {
   field(SCAN, "Passive")
   field(DTYP, "asynFloat64")
   field(OUT, "@asyn($(EQPT):Write_IConsFLE 0)FLOAT32_LE")
}

here is my drvModbusAsynConfigure:
drvModbusAsynConfigure("AR-GT7-PC3:Write_IConsFLE", "AR-GT7-PC3", 255, 16 , 5 ,  2 , 7 ,   1 , "InterfaceIocaste")

do you see any incorrect setting ?

Regards

Le 05/04/2012 17:25, Eric Norum a écrit :
> On Apr 5, 2012, at 7:19 AM, haquin wrote:
>
>> Hi Mark,
>>
>> I started to test the new release R2-4 of your modbus driver,
>>
>> 1/ I have a regression problem:
>> in case of "intarray_in" when scan mode is I/O Intr:
>> Linux IOC crashes with segmentation error message
> Could you run this again under GDB and send a stack trace?
>
>> VxWorks IOC doesn't crash but data in the waveform are equal to zero
>>
>> On Linux if I start with the scan mode set to none there is no crash.
> What happens if you change the mode to I/O Intr after the IOC has started?
>
>> In both cases linux and VxWorks,
>> if I change the scanning mode to any periodic scan (with a caput in the SCAN field), I do retreive correct data.
>>
>> here is my drvModbusAsynConfigure
>> drvModbusAsynConfigure("AR-GT7-PC3:Read_All",    "AR-GT7-PC3", 255,  4 , 0 , 46 , 0 ,  2000 , "InterfaceIocaste")
>>
>> here is my waveform:
>> record(waveform, "$(EQPT):ReceiveModbusTable") {
>>   field(DTYP, "asynInt32ArrayIn")
>>   field(FLNK, "$(EQPT):TrigModbusTableProcessing")
>>   field(INP, "@asyn($(EQPT):Read_All 0)MODBUS_DATA")
>>   field(NELM, "46")
>>   field(FTVL, "LONG")
>>   field(SCAN, "I/O Intr")
>> }
>>
>> 2/ I have tested the retreival of float32_LE with ai record, this is ok
>>
>> tomorrow I'll test retreival of int32 and also he writting.
>>
>> best regards.
>>


Replies:
Re: Proposed support for additional Modbus data types haquin
References:
Proposed support for additional Modbus data types Mark Rivers
RE: Proposed support for additional Modbus data types Mark Rivers
Re: Proposed support for additional Modbus data types haquin
RE: Proposed support for additional Modbus data types Mark Rivers
Re: Proposed support for additional Modbus data types haquin
Re: Proposed support for additional Modbus data types Eric Norum
Re: Proposed support for additional Modbus data types haquin

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