RE: Proposed support for additional Modbus data types

[Mark Rivers <rivers@cars.uchicago.edu>]

Hi Eric,

> What does SCAN=I/O Intr mean for output records?  Is that even supported?

The output is record is not I/O Intr scanned, it is Passive.  The part of his message relating to I/O Intr scanning is for his input waveform record, shown in a previous message.

> A one millisecond polling interval seems rather short.  Perhaps things simply don't have time to finish processing at that rate.

No, this is not correct.  This is an output Modbus operation (function code=16, write multiple registers). A non-zero poll value just means that the driver should do one initial readback so that the output record matches the hardware at iocInit.  The actual value of the poll time is irrelevant.

Mark


-----Original Message-----
From: Eric Norum [mailto:wenorum@lbl.gov] 
Sent: Friday, April 06, 2012 10:34 AM
To: haquin
Cc: tech-talk Talk; Mark Rivers
Subject: Re: Proposed support for additional Modbus data types

On Apr 6, 2012, at 7:46 AM, haquin wrote:

> 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")
> }

What does SCAN=I/O Intr mean for output records?  Is that even supported?

> 
> 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 ?

The arguments to drvModbusAsynConfigure are
drvModbusAsynConfigure(portName,		"AR-GT7-PC3:Write_IConsFLE",
                       tcpPortName,					"AR-GT7-PC3"
                       slaveAddress, 				255
                       modbusFunction, 				16
                       modbusStartAddress, 			5
                       modbusLength,				2
                       dataType,					7
                       pollMsec, 					1
                       plcType);						"InterfaceIocaste"


A one millisecond polling interval seems rather short.  Perhaps things simply don't have time to finish processing at that rate.

Records using the new drvUser feature (e.g. the FLOAT32_LE in the OUT field shown above)  can specify the registers as dataType=0 -- this is handy since you can mix integer and floating values in a single I/O block.



-- 
Eric Norum
wenorum@lbl.gov