PREFLASH:
light the preflash lamps
This page is part of the ING document
INS-DAS-24:
client-server interface for control of cameras
Purpose: light the preflash lamps, to provide a controlled illumination
for testing the detectors.
Actors: udas_run client, udas_camera_server, camera.
Outline: The client invokes the preflash action. The server orders the
camera to light the lamps for the appropriate time.
Normal course of events:
-
Client invokes the PREFLASH action on the server with these arguments:
-
Argument1 is the length of the illumination in seconds. values 0 to 8s
are valid.
-
Server validates the arguments.
-
Server orders camera to light the lamps for the required time.
-
Camera lights the lamps.
-
Camera sends back to server that the flash is complete.
-
Server returns good status to client.
Variations:
-
Client does not send arguments in the invocation of the action. Server
uses a default time for the preflash, the default being set in the server's
configuration file.
-
Server is using a default duration and that duration is less than 1ms.
Server skips steps 3..5 and goes to step 6.
-
At step 2, the flash duration is invalid. Server skips steps 3..5 and returns
status UDAS__BADEXPTIME to client.
-
Camera has no preflash lamps or the lamps do not work. Camera does know
this, so all steps except step 4 proceed normally.
-
Camera does not reply to server. Server sends status UDAS__CAMLINKDOWN
to client.