Experimental Physics and
Industrial Control System

Dirk Zimoch <[email protected]> · Tue, 28 May 2013 11:54:41 +0200

On 25.05.2013 14:24, Sebastian Matkovich wrote:

rod gave me the right solution, in the first string i send i tell the
device which channel i want to speak to and in the next string i send my
command :)

Just make sure that the channel selection and the command happen in the

same record processing. Using 2 protocols in two records, one for

selecting the channel and one for the command is not reliable because

someone may change the channel before you can send the command.

If you have many protocols that need to select the channel you may

define your own string like this:

ch = "CHANNEL %(\1:CH)%d:";

commandA { out $ch "commandA %f"; }
commandB { out $ch "commandB %s"; }
commandC { out $ch "commandC %d"; }

or you can define a sub-protocol and call it like this:

setch { out CHANNEL %(\1:CH)%d"; }

commandA { setch; out "commandA %f"; }
commandB { setch; out "commandB %s"; }
commandC { setch; out "commandC %d"; }

Dirk

2013/5/22 Rod Nussbaumer <[email protected] <mailto:[email protected]>>

    Or he may mean channels within a device or module, such as channels
    within an oscilloscope or multichannel digitizer. In such cases, the
    method should be documented by the vendor of the device. There is no
    generic method or streamDevice-specific method for performing such
    selections.
    A couple of things may be worth noting. In some cases, there is a
    specific SCPI command that effectively says 'for all subsequent
    commands, use channel n'. Where you are monitoring more than one
    channel on a periodic schedule, you can put that command into a
    single streamDevice protocol that may contain other commands that
    relate to that specific channel. You would probably do so for a
    number of protocols where you want to address specific channels.
    Moreover, a single protocol may be contrived that will work for all
    channels, where the channel number (or other identifier) is a macro
    variable (like \$1) that is passed to the protocol. The channel
    identifier might also be a PV such as an analog record or a multibit
    binary record, and this can be referenced an decoded in the protocol.

    If Sebastian has a different meaning for the question, he should
    rephrase and expand on his intention.

        ---   rod.

    On 05/22/2013 07:18 AM, Mark Rivers wrote:

        I think he probably means the asyn "addr" field, used to select
        a specific address or channel of a device.

        Mark

        __________________________________________
        From: [email protected]
        <mailto:[email protected]>
        [[email protected]
        <mailto:[email protected]>__] on behalf of Dirk
        Zimoch [[email protected] <mailto:[email protected]>]
        Sent: Wednesday, May 22, 2013 4:24 AM
        To: [email protected] <mailto:[email protected]>
        Subject: Re: streamdevice

        On 21.05.2013 18 <tel:21.05.2013%2018>:45, Sebastian Matkovich
        wrote:

            is it possible that you cannot access specific channels of a
            device
            through streamdevice? or does somebody know how to do that?

        What do you mean with "specific channels of a device"?

        Dirk

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System