Experimental Physics and
Industrial Control System

From: Li, Ji <liji at bnl.gov>
Sent: Thursday, December 24, 2020 5:36 PM
To: Mark Rivers <rivers at cars.uchicago.edu>
Cc: tech-talk at aps.anl.gov
Subject: 回复: Reading multiple parameters from an incoming message.

Hi Ji Li,


Can you send the rest of the database and protocol files, or at least the Status record and the $ax_status definition.

> The PV was showing INVALID(UDF_ALARM). Since the IOC didn't throw errors, I suppose the message was parsed correctly. How could this alarm have been caused?

Which PV are you referring to?

Mark



________________________________
From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Li, Ji via Tech-talk <tech-talk at aps.anl.gov>
Sent: Thursday, December 24, 2020 11:04 AM
To: tech-talk at aps.anl.gov
Subject: Reading multiple parameters from an incoming message.

Hi,

I'm working on an EPICS package for a Harvard Pump 33 DDS syringe pump using streamdevice protocols. I need to read several parameters from an incoming message that combines the status of two axes/syringes, which has the following format:

RATEA TIMEA VOLA STATUSA
RATEB TIMEB VOLB STATUSB

RATEA/B, TIMEA/B and VOLA/B are integers, and STATUSA/B are 6-character strings with each character indicating a specific status.

I'm trying to parse the message using multiple protocols and records. For RATEA, only grab the first integer:

Protocol:
=======================
getStatusRateAxA {
    out "status";
    in "%d %*d %*d %*c%*c%*c%*c%*c%*c\n%*d %*d %*d %*c%*c%*c%*c%*c%*c\n" $ax_status;
}
=======================

Record:
=======================
record(ai, "$(P){$(Q)-Ax:A}:RATE:RBV") {
  field(DESC, "Axis A rate readback")
  field(DTYP, "stream")
  field(INP, "@pump33dds.proto getStatusRateAxA($(P), $(Q), $(CMD)) $(PORT)")
  field(PREC, "0")
}
=======================

The .substitutions file referring to this record was loaded without errors. When I tried to retrieve status information, the IOC shell printed the following information without errors:

=======================
epics> 2020/12/24 11:29:06.797 /dev/ttyUSB0 write 8
status\r\n
2020/12/24 11:29:06.833 /dev/ttyUSB0 read 71
50000000000 0 22307784 w...I.\n83333333330 24723 2055394602192 i...I.\n::
=======================

"::" in the incoming message should be parsed by "$ax_status" in the protocol and it worked for other messages.

The PV was showing INVALID(UDF_ALARM). Since the IOC didn't throw errors, I suppose the message was parsed correctly. How could this alarm have been caused?

Best,

-Ji Li