Remote IOCs

Purpose

Remote IOCs are used when:

There is a piece of equipment that is mobile (i.e. not a permanent part of any beamline)
Diagnostics from the equipment are useful even when it is not connected to any beamline
The kit is physically capable of running an IOC

The first piece of equipment to use this is likely to be the Triton dilution fridges.

Configure the remote PC like a mini-inst, but with an empty startup.txt so that it starts no IOCs.
Run start_ibex_server.bat so that appropriate services (e.g. PSCTRL, conserv) start
Run call C:\Instrument\Apps\EPICS\ISIS\inst_servers\master\start_remote_ioc_server.bat on the remote PC to start the remote IOC server.
Run caput -S %MYPVPREFIX%REMIOC:INSTRUMENT IN:<local instrument>: to configure the remote ioc server to point at the relevant instrument
On the instrument control NDX computer, go to the IBEX configuration menu and set the "Remote PV prefix" for the IOC to the prefix of the remote machine (e.g. ME:<name of equipment>:)
To see the needed field in the GUI set ALLOW_REMOTE_PV_PREFIX_CHANGE to true. (uk.ac.stfc.isis.ibex.ui.configserver/src/uk/ac/stfc/isis/ibex/ui/configserver/editing/iocs/dialog/EditPanel.java)

architecture of the remote IOC

Local PC (NDX instrument control computer):

User edits configuration in GUI. There is a new option to select the "remote pv prefix" - if non-empty, this signifies that the IOC will run remotely.
The local blockserver receives the configuration and saves it as normal. The "remote pv prefix" property is stored in the configuration XML.
The blockserver does not stop/start/restart any local IOC if it is marked as having a remote PV prefix.

Remote PC:

The remote PC is configured to monitor a given instrument. This configuration must be done locally (on the remote PC). Currently this is done by caput -S %MYPVPREFIX%REMIOC:INSTRUMENT TE:NDW1799: to monitor NDW1799's configuration.
The remote ioc server sets up an EPICS monitor on the blockserver of the configured instrument
When the remote ioc server gets a monitor, it writes the parts of the config which have the same remote pv prefix as itself to file (in XML format, same as what the blockserver uses).
After writing the config XML, it restarts all of the IOCs which it's looking after