V4 Use Cases - Revision history

KayKasemir: Added thoughts from EPICS meeting

2005-10-11T15:05:51Z

Added thoughts from EPICS meeting

← Older revision		Revision as of 15:05, 11 October 2005
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	=== Command-line tools for debugging and scripting ===		=== Command-line tools for debugging and scripting ===
	1. ~~Dump the current "value" property of the channel "fred"~~.		1. List all channels that match a given name pattern.

	2. Dump ~~all properties, their type, and~~ current value ~~for a given~~ channel.		2. Dump the current "value" property of the channel "fred".

	3. Dump ~~the timestamp~~, value~~, units, status, severity of "fred" once~~ a ~~second~~.		3. Dump all properties, their type, and current value for a given channel.

	4. ~~... whenever any of~~ the timestamp, ~~...~~ severity ~~change~~.		4. Dump the timestamp, value, units, status, severity of "fred" once a second.

	5. ~~List all events that a PV supports: On change, 1Hz, RF Pulse, Beam Pulse~~, ...		5. ... whenever any of the timestamp, ... severity change.

	6. Dump the value of the cavity waveform for every beam pulse.		6. List all events that a PV supports: On change, 1Hz, RF Pulse, Beam Pulse, ...

			7. Dump the value of the cavity waveform for every beam pulse.

	~~7. List all channels that match a given name pattern.~~

	=== Display Manager ===		=== Display Manager ===
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	BPM-related ideas		BPM-related ideas

	1. List all channels available that are BPMs		1. List all channels available that are BPMs.

	2. Select all of them in sector 6		2. Select all of them in sector 6

	3. Display them when the beam is going to the end station A (one of 8 destinations possible)		3. Get the values of all BPMs in a sector, once, as a snapshot. This means all the BPMs must be read at the same time, for the same beam pulse, or whatever a specific site considers "at once".
			A variant would be: Display them when the beam is going to the end station A (one of 8 destinations possible)

	4. Same, but display ~~all BPMs on~~ the .1 Hz event		4. Same, but display them periodically, for example on the .1 Hz event

			5. Find the corrector magnet PVs that belong to a list of BPMs. Read the BPMs and current maget settings "at once", compute new settings, write the new settings "at once".
			<p>
	Scan a probe in the beam line		Scan a probe in the beam line

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	3. Given that there is a new view defined in the stepper motor that includes all motor readback data:Subscribe to counterClockWiseLimit, clockWiseLimit, moving, doneRetries, homeLimit at 10 Hz.		3. Given that there is a new view defined in the stepper motor that includes all motor readback data:Subscribe to counterClockWiseLimit, clockWiseLimit, moving, doneRetries, homeLimit at 10 Hz.

			=== Infrastructure for various applications ===
			1. Serialize and de-serialize the data type description in human-readable form.<br>

			1.1 Used to get common syntax for user-input to command line tools or for the archiver config file, where users need to describe what to get/put/archive and how:<br>
			'value' as double, 'units' as string, ...

			1.2 Used to get common output from tools that 'dump' the data type for info or debug purposes.

			2. Serialize and de-... in rather compact form

			2.1 Used by data storage tools to store the type information in the header of data blocks.

			2.2 Maybe also used by the network layer to initially xfer the data types.

			Could those formats be the same, i.e. a short yet human readable format?

			"{d:value,s:units,{d:low,d:high}limits}"

			could describe this structure:
			{
			double value;
			string units;
			struct
			{
			double low;
			double high;
			} limits;
			}

			3. Need to provide standard serialization of the data type description _and_ the data? Or should the developers of the network layer and archiver each invent their own?

KayKasemir: Tried to format it better. Still ugly.

2005-07-18T19:30:30Z

Tried to format it better. Still ugly.

← Older revision		Revision as of 19:30, 18 July 2005
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			== Overview ==

			These are example use cases where we need to assert that each layer of EPICS V4 handles them:

			1. Can the CA client user API articulate the request?

			2. Can the network protocol transfer the request?

			3. Do the database & drivers understand the request and provide the necessary data?

			4. Does the data get back up to the client in the appropriate form and at the requested time?

	== Use Cases ==		== Use Cases ==

	~~These are examples that need to get handled~~		=== Command-line tools for debugging and scripting ===
	by the ~~CA client user API,~~ the ~~network protocol~~,		1. Dump the current "value" property of the channel "fred".
	~~the database~~, ~~down to drivers~~ and ~~back up to~~
	~~the client~~.		2. Dump all properties, their type, and current value for a given channel.

	~~=== Command-line tools for debugging and scripting ===~~
	~~1. Dump the current "value" of the channel "fred".~~
	~~2. Dump all properties, their type, current value for a given channel.~~
	3. Dump the timestamp, value, units, status, severity of "fred" once a second.		3. Dump the timestamp, value, units, status, severity of "fred" once a second.

	4. ... whenever any of the timestamp, ... severity change.		4. ... whenever any of the timestamp, ... severity change.

	5. List all events that a PV supports: On change, 1Hz, RF Pulse, Beam Pulse, ...		5. List all events that a PV supports: On change, 1Hz, RF Pulse, Beam Pulse, ...

	6. Dump the value of the cavity waveform for every beam pulse.		6. Dump the value of the cavity waveform for every beam pulse.

			7. List all channels that match a given name pattern.

	=== Display Manager ===		=== Display Manager ===
	1. Display an analog input value on a bar		1. Display an analog input value on a bar:<br>
	Get limits, subscribe to values, receive value & display it, receive change-of-display-range notification,...		Get limits, subscribe to values, receive value & display it, receive change-of-display-range notification,...
	2. Display a menu output for a 2 state valve on a text update
	Get state strings, subscribe to (numeric?) value, display incoming data, receive state string updates, ...		2. Display a menu output for a 2 state valve on a text update:<br>
	3. Give a controller for a 2 state valve controller on a radio button		Get state strings, subscribe to (numeric?) value, display incoming data, receive state string updates, ...
	Handle same as 2?
	4. Display a waveform on an xy plot		3. Give a controller for a 2 state valve controller on a radio button.<br>Handle same as 2?
	Similar to 1, but array data?
			4. Display a waveform on an xy plot.<br>
			Similar to 1, but array data?

	5. Attempt to display a string on a bar		5. Attempt to display a string on a bar
	6. Universal PV Inspector:
	Get properties, allow user to select properties.		6. Universal PV Inspector:<br>
	If writeable string -> display text entry field		Get properties, allow user to select properties.<br>
	If read-only string -> display text update field		If writeable string -> display text entry field.<br>
	If writeable numeric with limits -> display slider with range of number		If read-only string -> display text update field.<br>
	....		If writeable numeric with limits -> display slider with range of number.<br>
			....

	7. Display as bars, a list of BPMs where I can set the offset in time to fetch (assuming that these BPMs are read as arrays that are all triggered at one time – but I want to see them at different points in time as it goes down the beamline).		7. Display as bars, a list of BPMs where I can set the offset in time to fetch (assuming that these BPMs are read as arrays that are all triggered at one time – but I want to see them at different points in time as it goes down the beamline).

	=== Physics Application ===		=== Physics Application ===
	1. BPM-related ideas
	1.1. List all channels available that are BPMs		BPM-related ideas
	1.2. Select all of them in sector 6
	1.3 Display them when the beam is going to the end station A (one of 8 destinations possible)		1. List all channels available that are BPMs
	1.4 Same, but display all BPMs on the .1 Hz event
			2. Select all of them in sector 6

			3. Display them when the beam is going to the end station A (one of 8 destinations possible)

			4. Same, but display all BPMs on the .1 Hz event


	2. Scan a probe in the beam line		Scan a probe in the beam line
	2.1 Find PVs for some beam line device:
	Stepper motors for probe's X & Y position, intensity of beam transmitted by probe,		1. Find PVs for some beam line device:<br>
	beam shutter open/close, beam available		Stepper motors for probe's X & Y position, intensity of beam transmitted by probe,
	2.2 Scan sequence:		beam shutter open/close, beam available
	Assert shutter is closed;
	move X/Y to 0/0, wait for completion		2. Scan sequence:<br>
	until done:		Assert shutter is closed;
	open shutter, wait until open		move X/Y to 0/0, wait for completion
	measure intensity for 1 second while beam_available		until done:
	close shutter		open shutter, wait until open
	move to next position, wait until you get there		measure intensity for 1 second while beam_available
			close shutter
			move to next position, wait until you get there

	=== Archiver ===		=== Archiver ===
	1. Get value, timestamp, status/severity of a channel once per second		1. Get value, timestamp, status/severity of a channel once per second
	2. Archive default properties of a channel using the default deadband
	How are they defined? How does the archiver learn about them?		2. Archive default properties of a channel using the default deadband.<br>
	3. Given that there is a new view defined in the stepper motor that includes all motor readback data:		How are they defined? How does the archiver learn about them?
	Subscribe to counterClockWiseLimit, clockWiseLimit, moving, doneRetries, homeLimit
	at 10 Hz.		3. Given that there is a new view defined in the stepper motor that includes all motor readback data:Subscribe to counterClockWiseLimit, clockWiseLimit, moving, doneRetries, homeLimit at 10 Hz.

KayKasemir at 19:15, 18 July 2005

2005-07-18T19:15:20Z

New page

== Use Cases ==

These are examples that need to get handled
by the CA client user API, the network protocol,
the database, down to drivers and back up to
the client.

=== Command-line tools for debugging and scripting ===
1. Dump the current "value" of the channel "fred".
2. Dump all properties, their type, current value for a given channel.
3. Dump the timestamp, value, units, status, severity of "fred" once a second.
4. ... whenever any of the timestamp, ... severity change.
5. List all events that a PV supports: On change, 1Hz, RF Pulse, Beam Pulse, ...
6. Dump the value of the cavity waveform for every beam pulse.

=== Display Manager ===
1. Display an analog input value on a bar
Get limits, subscribe to values, receive value & display it, receive change-of-display-range notification,...
2. Display a menu output for a 2 state valve on a text update
Get state strings, subscribe to (numeric?) value, display incoming data, receive state string updates, ...
3. Give a controller for a 2 state valve controller on a radio button
Handle same as 2?
4. Display a waveform on an xy plot
Similar to 1, but array data?
5. Attempt to display a string on a bar
6. Universal PV Inspector:
Get properties, allow user to select properties.
If writeable string -> display text entry field
If read-only string -> display text update field
If writeable numeric with limits -> display slider with range of number
....
7. Display as bars, a list of BPMs where I can set the offset in time to fetch (assuming that these BPMs are read as arrays that are all triggered at one time – but I want to see them at different points in time as it goes down the beamline).

=== Physics Application ===
1. BPM-related ideas
1.1. List all channels available that are BPMs
1.2. Select all of them in sector 6
1.3 Display them when the beam is going to the end station A (one of 8 destinations possible)
1.4 Same, but display all BPMs on the .1 Hz event

2. Scan a probe in the beam line
2.1 Find PVs for some beam line device:
Stepper motors for probe's X & Y position, intensity of beam transmitted by probe,
beam shutter open/close, beam available
2.2 Scan sequence:
Assert shutter is closed;
move X/Y to 0/0, wait for completion
until done:
open shutter, wait until open
measure intensity for 1 second while beam_available
close shutter
move to next position, wait until you get there

=== Archiver ===
1. Get value, timestamp, status/severity of a channel once per second
2. Archive default properties of a channel using the default deadband
How are they defined? How does the archiver learn about them?
3. Given that there is a new view defined in the stepper motor that includes all motor readback data:
Subscribe to counterClockWiseLimit, clockWiseLimit, moving, doneRetries, homeLimit
at 10 Hz.