Overview of uEcho Controller

The controller is a special node of ECHONETLite to control other nodes, it can find the nodes in the local area network and send any messages into the found devices.

Creating Controller

1. Starting Controller

To start a controller, create a controller using uecho_controller_new and start the controller using uecho_controller_start as the following:

#include <uecho/uecho.h>

uEchoController *ctrl = uecho_controller_new();
uecho_controller_start(ctrl);

2. Searching Nodes

Next, use uecho_controller_search to search other nodes in the local area network as the following:

uEchoController *ctrl;
....
uecho_controller_search(ctrl);

3. Getting Nodes and Objects

After the searching, use uecho_controller_getnodes and uecho_node_next to get all found nodes. The ECHONETLite node might have multiple objects such as the device or profile objects, use uecho_node_getobjects and uecho_object_next to get the all objects in the node.

uEchoController *ctrl;
....
uEchoNode *node;
uEchoObject *obj;

for (node = uecho_controller_getnodes(ctrl); node; node = uecho_node_next(node)) {
  for (obj = uecho_node_getobjects(node); obj; obj = uecho_object_next(obj)) {
    printf("%s %06X\n", uecho_node_getaddress(node), uecho_object_getcode(obj));
  }
}

4. Creating Request Message

To control the found objects, create the request message using uecho_message_new() as the following.

uEchoMessage *msg;
msg = uecho_message_new();
uecho_message_setesv(msg, 0xXX);
uecho_message_setdestinationobjectcode(msg, 0xXXXXXX);
uecho_message_setproperty(msg, epc, ..., ...);
....

To create the message, developer should only set the following message objects using the message functions.

ESV : ECHONET Lite service
DEOJ : Destination ECHONET Lite object specification
EPC : ECHONET Lite Property
PDC : Property data counter
EDT : Property value data

The uEcho controller sets the following message objects automatically when the message is sent.

EHD1 : ECHONET Lite message header 1
EHD2 : ECHONET Lite message header 2
TID : Transaction ID
SEOJ : Source ECHONET Lite object specification
OPC : Number of processing properties

5. Sending Messages

To send the created request message, use uecho_controller_sendmessage as the following:

uEchoController *ctrl;
uEchoNode *dstNode;
uEchoMessage *msg;
....
uecho_controller_sendmessage(ctrl, dstNode, msg);

Basically, all messages of ECHONETLite is async. To handle the async response of the message request, use uecho_controller_postmessage as the following:

uEchoController *ctrl;
uEchoNode *dstNode;
uEchoMessage *msg, *resMsg;
....
resMsg = uecho_message_new();
if (uecho_controller_postmessage(ctrl, dstNode, msg, resMsg)) {
  ....  
}
uecho_message_delete(resMsg);

Next Steps

Let's check the following documentation to know the controller functions of uEcho in more detail.

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