DAE Pre and Post commands

It is possible to get additional actions to be carried out by DAE IOC when commands such as begin/end/pause/resume/abort are executed. These actions are typically used to do things like open/close an intermediate (fast) shutter. A PRE action is executed before the command and a POST after it has run. Whether the IOC waits for a PRE/POST to complete before the next action is controlled by whether PP or CA is passed as part of configuration, CA will wait for a completion callback and PP will just inititate processing. The PV specified will have the number 0 written to it for a PRE action and 1 for a POST action, usually you will specify the .PROC of a PV so just processing is initiated, but you can specify e.g. the .VAL and it will get 0 or 1 written to it as appropriate

The PV links to access are set by macros, either in the configuration or in globals.txt. The have names like PRE_BEGIN_1 and POST_BEGIN_1, to specif in globals you would add something like

ISISDAE_01__PRE_BEGIN_1=TE:NDW2127:DAE:DUMMYPRE PP

Not the PP added at the end to request processing