some_pv_namethis will refer to a default PV type which can be configured in the PV preferences.
To select a specific PV type, use the PV name format
type://some_pv_name
Name | Detail |
---|---|
sys://time | Local date and time |
sys://free_mb | Free Java VM memory in MB |
sys://used_mb | Used Java VM memory in MB |
sys://max_mb | Maximum available Java VM memory in MB |
sys://user | User Name |
sys://host_name | Host name |
sys://qualified_host_name | Full Host Name |
sys://system.* | Any system property, e.g. "sys://system.user.name" |
sys://pv_count | Number of "loc:", "sys:" and "sim:" values. |
ca://some:record:name ca://some_record_name ca://some_record_name.SCANThe "ca://" prefix can be avoided by configuring it as the default.
loc://demoWhen adjusting the value in Probe, the Data Browser will reflect the changes.
Note that if no initial value specified, local PVs have a default initial value of 0. Setting them to anything that parses as a number will create a numeric (double-typed) PV. Otherwise, they behave as String PVs.
You can also give an initial value to a local PV by following one of these formats:
loc://demo(1.23)will initialize it to a double value of 1.23.
loc://demo(1.23, 2.2, 3, 4.5, 6.7)will initialize it to a double array.
loc://demo(hello)will initialize it to a string value of "hello".
Note that if initial values differ between two declarations, the first one wins.
sim://noisegenerates simulated noise from -5 to 5, updating once every second.
sim://noise(-10, 10, 0.2)generates simulated noise from -10 to 10, updating every 0.2 seconds.
sim://sine(0, 10, 20, 0.5)generates a simulated sine wave signal valued 0 to 10, split into 20 updates, updating every 0.5 seconds. A full period takes 20 updates, i.e. 5 seconds in this example.
sim://ramp(0, 10, 0.1, 0.5)generates a ramp (saw-tooth) valued 0 to 10, stepping 0.1 every 0.5 seconds.
sim://ramp(0, 100, -1, 2)generates a negative ramp, i.e. count-down, from 100 to 0, stepping 1 every 2 seconds.
const://pi(3.14)a constant double value of 3.14.
const://name(Fred)a constant string value of "Fred". As a shortcut, just
3.14 "Fred"will have the same effect.
const://arrayDemo(1.23, 2.2, 3, 4.5, 6.7)a constant double array.
Constant PVs are read-only, and only send one initial value update.