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Realtime mode

GridLAB-D can be run as realtime system emulator by setting the global variable run_realtime to a non-zero value, e.g.,

 host% gridlabd -D run_realtime=1 modelname.glm

In realtime mode, GridLAB-D will attach the internal simulation clock to the system clock. GridLAB-D will update the model at most once per second.

While running in realtime mode, the stop time is used to stop the simulation. If the stop time is not set or it was set to a time before the start time (in real time), then the simulation will run indefinitely until it receives a signal to stop.

Server mode

Server mode is essential to the realtime mode and allows a web-based application to access the global variable and properties of named objects.

To start GridLAB-D in server mode, simply include the command line argument --server, e.g.,

 host% gridlabd modelname.glm --server

Prior to Keeler (Version 4.0):

To get the value of a global variable, use the following query

 host% wget http://hostname:6267/variable-name -q -O -

To get the value of an object property, use the following query

 host% wget http://hostname:6267/object-name/property-name -q -O -

To set the value of an object property, use the following query

 host% wget http://hostname:6267/object-name/property-name=value -q -O -

The value can include units (separate by a space) and they will be converted automatically. The value is read back after is set to confirm that it was accepted (including unit conversion).

As of Keeler (Version 4.0):

To get the value of a global variable, use the following query

 host% wget http://hostname:6267/method/variable-name -q -O -

where the method can be raw, json, or xml. To get the value of an object property, use the following query

 host% wget http://hostname:6267/format/object-name/property-name -q -O -

If you use the xml method, you can specify formatting by appending the specifications to the property name, e.g.,

 host% wget http://hostname:6267/format/object-name/property-name[spec] -q -O -

The format specification is structured as follows for double values

 [unit,precision format]

and for complex values

 [unit,precision format part]

The unit must be compatible with the unit of the value given. The precision must be a single digit from 0 to 9. The format must be one of a, f, e, g, A, F, E, G, as interpreted by printf(). The part may 'i' or 'j' for complex rectangular, 'd' for complex polar with angle in degrees, 'r' for complex polar with angle in radians, 'M' for magnitude, 'D' angle only in degree, 'R' for angle only in radians.

To set the value of an object property, use the following query

 host% wget http://hostname:6267/format/object-name/property-name=value -q -O -

The value can include units (separate by a space) and they will be converted automatically. The value is read back after is set to confirm that it was accepted (including unit conversion).

Control

 New in 3.0!  (as of Grizzly:2732)

To pause the simulation at a specified time, use the following query:

 host% wget 'http://hostname:6267/control/pauseat=YYYY-MM-DD HH:MM:SS ZZZ'

Note that if the simulation is already paused and the time given is later than the current time, it will resume the simulation and pause at the specified time.

To resume the simulation when it is paused, use the following query:

 host% wget http://hostname:6267/control/resume

In this case, the simulation will run until the stoptime or steady state is reached, whichever comes first.

To shutdown the simulation, use the following query:

host% wget http://hostname:6267/control/shutdown

XML

Prior to Keeler (Version 4.0)

To read data entities, use the following query:

 host% wget http://hostname:6267/xml/specification

where the specification may take the forms

To write data entities, use the following query:

 host% wget http://hostname:6267/xml/specification=value

The value may includes units if unit conversion is needed:

 host% wget 'http://hostname:6267/xml/specification=value unit'

Output

Output files may be requested using the query:

 host% wget http://hostname:6267/output/filename.ext

Only files in the working directory or subdirectories thereof may be accessed.

The response to global variable requests will be in the form

 <globalvar>
   <name>variable_name</name>
   <value>value[ unit]</value>
 </globalvar>

The response to object property requests will be in the form

 <property>
   <object>object_name</object>
   <name>property_name</name>
   <value>value[ unit]</value>
 </property>

Runtime Files

Some client support functions require runtime libraries that are provided by the server. To read a runtime library use the query

 host% wget http://hostname:6267/rt/library_name

The library content is returned. For example, to read the default javascript library, use the query

 host% wget http://hostname:6267/rt/gridlabd.js

As of Keeler (Version 4.0)

Any global variable name surrounded by '<<<' '>>>' will be substituted on the server-side.

Server-side applications

Some server-side applications may be installed for a server and called by clients by using the query

 host% wget http://hostname:6267/appname/scriptname

The following applications are currently supported if they are installed on the server:

Server applications
Application App Name Script Extension
Perl perl .pl
GnuPlot gnuplot .plt
Python python .r
Java java .jar
R r .r
Scilab scilab .cse
Octave octave .m

In all cases the output is copied to the client. Typically, it is the HTML code needed to properly embed the result of the script.

See also