EPICS client discovery variables
The exercises use explicit loopback searches so clients find an IOC on the same host. Activate the selected EPICS tree in every terminal.
| Variable | Role in these lessons |
|---|---|
EPICS_CA_ADDR_LIST | UDP destinations for Channel Access searches |
EPICS_CA_AUTO_ADDR_LIST | Adds automatic interface broadcast addresses when YES |
EPICS_PVA_ADDR_LIST | UDP destinations for pvAccess searches |
EPICS_PVA_AUTO_ADDR_LIST | Adds automatic interface broadcast addresses when YES |
EPICS_PVA_NAME_SERVERS | Optional TCP name servers for PVA discovery |
For an IOC on this host, use these client settings:
export EPICS_CA_AUTO_ADDR_LIST=NO EPICS_CA_ADDR_LIST=127.0.0.1
export EPICS_PVA_AUTO_ADDR_LIST=NO EPICS_PVA_ADDR_LIST=127.0.0.1
An explicit address list and automatic addresses are separate settings.
Setting a list does not by itself disable automatic broadcast searches.
Use addresses reachable from the client for remote IOCs; 127.0.0.1
always refers to the client’s own host.
To inspect this host’s IPv4 addresses, use:
ip -4 addr show
Discovery locates the server; subsequent data operations use a TCP connection. Successful discovery alone does not establish that a device is connected or a record has valid data. Read the value and its alarms.
The PVXS network configuration reference describes PVA client and server settings beyond these local exercises.