Experimental Physics and
Industrial Control System

Mark Rivers via Tech-talk <tech-talk at aps.anl.gov> · Wed, 30 Dec 2020 13:51:34 +0000

Hi Ji Li,

> The protocols without InTerminator work for me, at least I can set parameters and read them out from the pump.

> I think asyn returns as soon as the input message matches the expected pattern - for most of them, $ax_status, such as "::".

No, that is not possible.  asyn does not know anything about the expected pattern.  The way stream device and asyn work is that stream device does a "read" from the asyn driver.  If asyn is configured with noProcessEos=0 (the default) then the asyn read will return when any of the following occur:

- The specified terminator is found.  You have not specified a terminator in your protocol file, so this cannot be happening unless you specified a terminator in your startup script.

- The specified number of characters has been read.  It is possible that streamDevice is only asking for 1 character, so it may return because of this.

- The specified timeout has occurred.

- EndOfMessage has been received.  This is only for GPIB.

> There're alarms for those PVs, but I doubt they are related to InTerminator.

The UDF alarm means the record has not processed successfully, so the value is undefined.

You should enable asynTrace on the underlying asyn driver, and you should set streamDebug so you can see what stream is doing.

Mark

________________________________
From: Li, Ji <liji at bnl.gov>
Sent: Tuesday, December 29, 2020 9:14 PM
To: Mark Rivers
Cc: tech-talk at aps.anl.gov
Subject: 回复: Reading multiple parameters from an incoming message.

Happy New Year, Mark.

This problem is still on my table and to be solved.

============================

Your .db file passes 3 arguments to the protocol file, %(P), $(Q), $(CMD).  But in the protocol file I only see \$1 and \$2, not \$3.  Is this correct?

The first two parameters $(P) and $(Q) are common for all records, so I assigned values to them in global{} in the .substitutions file. The command sent out by this specific protocol is "status" which was hard coded it in the protocol (for others protocols the commands vary), so $(P) and $(Q) are sufficient for this record. I put $(CMD) in it as a dummy argument since I could not make empty substitution in the .substitutions file as loading

----------------------------

file "$(HARVARD)/db/pump33dds-ax-status-a.db"

{

pattern

}

----------------------------

throws errors.

But I think would be an good idea to make use of $(CMD) for disambiguation.

============================
You have commented out the line that defines the input terminator in the protocol file:

#InTerminator = 0x11;

How will asyn know when to return a string without a timeout if there is no terminator defined?

The returned messages from the pump don't have terminators. When InTerminator was defined, asyn would not return until timeout. The protocols without InTerminator work for me, at least I can set parameters and read them out from the pump. I think asyn returns as soon as the input message matches the expected pattern - for most of them, $ax_status, such as "::".

There're alarms for those PVs, but I doubt they are related to InTerminator.

 ============================

I think the protocol would be easier to read if you change this:

in "%d %*d %*d %*c%*c%*c%*c%*c%*c\n%*d %*d %*d %*c%*c%*c%*c%*c%*c\n" $ax_status;

to this:

in "%d %*d %*d %*6c\n%*d %*d %*d %*6c\n" $ax_status;

This looks much better. I updated the protocol.
============================

Best,

-Ji Li

________________________________
发件人: Mark Rivers <rivers at cars.uchicago.edu>
发送时间: 2020年12月29日 18:45
收件人: Li, Ji <liji at bnl.gov>
抄送: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
主题: RE: Reading multiple parameters from an incoming message.

Hi Ji Li,

Sorry for the delay in replying.  Maybe you have figured this out?

If not, I have some questions:

Your .db file passes 3 arguments to the protocol file, %(P), $(Q), $(CMD).  But in the protocol file I only see \$1 and \$2, not \$3.  Is this correct?

You have commented out the line that defines the input terminator in the protocol file:

#InTerminator = 0x11;

How will asyn know when to return a string without a timeout if there is no terminator defined?

I think the protocol would be easier to read if you change this:

in "%d %*d %*d %*c%*c%*c%*c%*c%*c\n%*d %*d %*d %*c%*c%*c%*c%*c%*c\n" $ax_status;

to this:

in "%d %*d %*d %*6c\n%*d %*d %*d %*6c\n" $ax_status;

Mark

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 Mark,

I was referring to the PV for RATEA - $(P){$(Q)-Ax:A}:RATE:RBV.

Please see the attached files for the protocol, the database, the substitutions file, and the st.cmd. I only worked on Independent Condition to operate the two syringes separately. For better clarity I removed other protocols/databases definitions.

The .proto file contains the definition of this protocol and the referenced macro.

I have several .db files for different categories of information (rate/volume/time/...). The attached .db file defines the status PV - currently only RATEA. I expect implementation of other PVs that get values from this status message would be similar once I'm done with RATEA.

Best,

-Ji Li

________________________________

发件人: Mark Rivers <rivers at cars.uchicago.edu<mailto:rivers at cars.uchicago.edu>>
发送时间: 2020年12月24日 14:53
收件人: Li, Ji <liji at bnl.gov<mailto:liji at bnl.gov>>
抄送: tech-talk at aps.anl.gov<mailto:tech-talk at aps.anl.gov> <tech-talk at aps.anl.gov<mailto:tech-talk at aps.anl.gov>>
主题: Re: 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<mailto:tech-talk-bounces at aps.anl.gov>> on behalf of Li, Ji via Tech-talk <tech-talk at aps.anl.gov<mailto:tech-talk at aps.anl.gov>>
Sent: Thursday, December 24, 2020 11:04 AM
To: tech-talk at aps.anl.gov<mailto: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

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System