Experimental Physics and
Hi all,We are experienceing some channel name anomalies in our systems.
I have Wireshark sniffing our control network to monitor Channel Access packets.
It's showing CA requests for channels that don't exist such as this one:
Command: Search (0x0006)
Payload Size: 24
Reply: Only for Success (0x0005)
Client Channel ID: 94
Param 2: 0x0000005e
PV Name: sad:dc:d_gdr_winYo4
The channel that is being searched for, sad:dc:d_gdr_winYo4 does not exist in any of our systems, but the name is missing a prefix for a legitimate channel, and it should be gsaoi:sad:dc:d_gdr_winSizeS. This channel is referenced as an input link to a different channe (it's an ai record)l:
tcs-cp-ioc> dbpr tcs:drives:odgwextent 10
ACKS: INVALID ACKT: YES ADEL: 0 ALST: 16
AOFF: 0 ASG: ASLO: 1 ASP: 0x0
BKPT: 00 DESC: Extent of ODGW window DISA: 0
DISP: 0 DISS: NO_ALARM DISV: 1 DPVT: 0x28b458
DSET: 0x28b458 DTYP: Soft Channel EGU: pixels EGUF: 0
EGUL: 0 EOFF: 0 ESLO: 1 EVNT: 0
FLNK:DB_LINK tcs:drives:odgw1x.VAL HHSV: NO_ALARM HIGH: 0
HIHI: 0 HOPR: 0 HSV: NO_ALARM HYST: 0
INIT: 0 INP:CA_LINK gsaoi:sad:dc:d_gdr_winSizeS CA NMS
LALM: 16 LBRK: 0 LCNT: 0 LINR: LINEAR
LLSV: NO_ALARM LOLO: 0 LOPR: 0 LOW: 0
LSET: 0x1c9c7e0 LSV: NO_ALARM MDEL: 0
MLIS: 00 00 00 00 00 00 00 00 00 00 00 00 MLOK: 01 8b c9 18
MLST: 16 NAME: tcs:drives:odgwextent NSEV: NO_ALARM
NSTA: NO_ALARM ORAW: 0 PACT: 0 PBRK: 0x0
PHAS: 0 PINI: NO PPN: 0x0 PPNR: 0x0
PREC: 1 PRIO: LOW PROC: 0 PUTF: 0
RDES: 0xae1f78 ROFF: 0 RPRO: 0 RSET: 0x28ac30
RVAL: 0 SCAN: 2 second SDIS:CONSTANT 0.000000000000000e+00
SEVR: NO_ALARM SIML:CONSTANT 0.000000000000000e+00 SIMM: NO
SIMS: NO_ALARM SIOL:CONSTANT 0.000000000000000e+00 SMOO: 0
SPVT: 0x1d01758 STAT: NO_ALARM SVAL: 0
TIME: 2019-07-19 15:41:03.662545919 TPRO: 0 TSE: 0
TSEL:CONSTANT UDF: 0 VAL: 16
The channel requesting the value ( tcs:drives:odgwextent) does seem to be getting the correct input value from the other channel (gsaoi:sad:dc:d_gdr_winSizeS):
$ caget gsaoi:sad:dc:d_gdr_winSizeS
$ caget tcs:drives:odgwextent
but as can be seen from the Wireshark capture, CA is also requesting the channel with an incomplete version of its name.
The channel with the bogus name (and several others) is being asked for many times per second, and we are concerned about unnecessary network traffic.
For reference, we are using EPICS R126.96.36.199 with RTEMS 4.10.2 on a MVME2700 CPU.
Can someone help us understand what's going on here?
Control Systems Software Engineer
|ANJ, 19 Jul 2019||
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