I have developed a model of motor speed control using variable frequency drive and established the server by defining OPC connection. The motor that I am using is asynchronous motor with parameters 5.5kw power and 1500 rpm. When I run the model and log the data through PLC , the value changes from full load condition to the fed value. For example , If I feed the rpm speed as 1000 rpm , the motor speed will first go to the full load condition i.e 1500 rpm and then go to 1000 rpm. What I want to do is the value should move from 0 to 1000 rpm(fed value). I am attaching the code that I am using for it.
function [x] = Read_OPC_Func(y)
% variables
persistent init_Server;
persistent init_Nodes;
persistent uaClient;
persistent Var_Node_In;
persistent Var_Node_Out;
persistent testVal;
% initialize variables
if (isempty(init_Server))
testVal = 0;
init_Server = 0;
init_Nodes = 0;
end
% OPC UA server (PLC) address and connecting client (Simulink) to the
% server
if init_Server == 0
init_Server = 1;
uaClient = opcua('172.16.4.20',4840);
connect(uaClient);
end
% define variable nodes in the server
if uaClient.isConnected == 1 && init_Nodes == 0
init_Nodes = 1;
% find DB "OpcInterface" of the server
%DB_Node = findNodeByName(uaClient.Namespace, 'OpcInterface', '-once');
% find variables "ref_speed" and "Motor_speed" in the DB "OpcInterface
Var_Node_In = opcuanode(3, '"OpcInterface"."ref_speed"',uaClient);
Var_Node_Out = opcuanode(3, '"OpcInterface"."Motor_speed"',uaClient);
end
% read and write variables of the server
if uaClient.isConnected == 1 && init_Nodes == 1
% read "ref_speed" value from server and store in "val"
[val, ~, ~] = readValue(uaClient, Var_Node_In);
% assign input y of the function to "Motor_speed" variable
writeValue(uaClient, Var_Node_Out, y);
% assign "val" to variable "testVal"
testVal = val;
end
% assign "Motor_Speed" ("testVal") value to the output x of the function
x = double(testVal);
end
