Experimental Physics and
Industrial Control System

Eric Norum <[email protected]> · Tue, 30 Sep 2008 11:33:07 -0500

On Sep 30, 2008, at 11:14 AM, marco_hair wrote:
 hi, Eric:
I follow your tutorial, but seems there is sth. wrong in my test code.
this is dbtr message:
epics> dbtr AB300:FilterWheel:fbk

ACKS: NO_ALARM ACKT: YES ADEL: 0 ALST: 0

ASG: BKPT: 0x00 DESC: Filter Wheel Position

DISA: 0 DISP: 0 DISS: NO_ALARM DISV: 1

DTYP: AB300 EGU: EVNT: 0
FLNK:CONSTANT 0

HHSV: NO_ALARM HIGH: 0 HIHI: 0 HOPR: 0

HSV: NO_ALARM HYST: 0 INP:GPIB_IO #L0 A0 @2

LALM: 0 LCNT: 0 LLSV: NO_ALARM LOLO: 0

LOPR: 0 LOW: 0 LSV: NO_ALARM MDEL: 0

MLST: 0 NAME: AB300:FilterWheel:fbk NSEV:
NO_ALARM

NSTA: NO_ALARM PACT: 1 PHAS: 0 PINI: NO

PRIO: LOW PROC: 0 PUTF: 0 RPRO: 0

SCAN: Passive SDIS:CONSTANT SEVR: INVALID
SIML:CONSTANT

SIMM: NO SIMS: NO_ALARM SIOL:CONSTANT STAT: UDF

SVAL: 0 TPRO: 0 TSE: 0
TSEL:CONSTANT

UDF: 1 VAL: 0

epics> 2008/10/01 00:11:33.540 192.168.1.103:4001 write 2

ª\201

epics> 2008/10/01 00:11:35.468 192.168.1.103:4001 read 4

U\020\000\020

2008/10/01 00:11:37.465 AB300:FilterWheel:fbk convert failed Invalid
reply
I change the code in devAB300.c like this:
  {&DSET_LI, GPIBREAD, IB_Q_LOW, "\252\201\000\201", NULL, 0, 10,
   convertCurrentReply, 0, 0, NULL, NULL, NULL},
why can I only send 2 bytes to device through an Ethernet/serial box?

You've hit a shortcoming in the devGpib support. The problem is with
the string you're trying to send. The devGpib code expects the
command/format strings to be null-terminated and thus sees the '\000'
in your command as the end of the string.

If there's no way to avoid sending the NUL character to instrument
you'll have to specify GPIBCVTIO in the command table entry and
perform all the I/O operations yourself in the custom conversion
routine.
Here's a very simple example from device support for a MAX1619 digital
thermometer. As you can see, the 'read local temperature' command
code (Param 2) is a NUL.
/*

* Custom I/O routines

*/

static int

readRegisterValue(struct gpibDpvt *pdpvt, int P1, int P2, char **P3)

{

struct longinRecord *pli = ((struct longinRecord *)(pdpvt-
>precord));

gpibCmd *pgpibCmd = gpibCmdGet(pdpvt);

asynOctet *pasynOctet = pdpvt->pasynOctet;

void *asynOctetPvt = pdpvt->asynOctetPvt;

size_t ntrans;

int eomReason;

char reply;
 if ((pasynOctet->write(asynOctetPvt,pdpvt->pasynUser,pgpibCmd->cmd,

1,&ntrans) != asynSuccess)

|| (pasynOctet->read(asynOctetPvt,pdpvt->pasynUser,&reply,

1,&ntrans,&eomReason) !=
asynSuccess)

|| (ntrans != 1)) {

return -1;

}

if (P1)

pli->val = (signed char)reply;

else

pli->val = (unsigned char)reply;

pli->udf = 0;

return 0;

}

.

.

.

.

/* Param 0 -- Read manufacturer ID code */

{&DSET_LI, GPIBCVTIO, IB_Q_LOW, "\xFE", NULL, 0, 1,

readRegisterValue, 0, 0, NULL, NULL, NULL},
    /* Param 1 -- Read Device ID code */
    {&DSET_LI, GPIBCVTIO, IB_Q_LOW, "\xFF", NULL, 0, 1,
        readRegisterValue, 0, 0, NULL, NULL, NULL},
    /* Param 2 -- Read local temperature */
    {&DSET_LI, GPIBCVTIO, IB_Q_LOW, "\x00", NULL, 0, 1,
        readRegisterValue, 1, 0, NULL, NULL, NULL},
    /* Param 3 -- Read remote temperature */
    {&DSET_LI, GPIBCVTIO, IB_Q_LOW, "\x01", NULL, 0, 1,
        readRegisterValue, 1, 0, NULL, NULL, NULL},

--
Eric Norum <[email protected]>
Advanced Photon Source
Argonne National Laboratory
(630) 252-4793

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System