KNX Write Protocol

gistfile1.m

- (void)changeStatusOfObject:(PCHousemasterObject *)object toValue:(float)value
{
    NSArray *groupAddressArray = [object.groupAddress componentsSeparatedByString:@"/"];
    
    NSString *groupAddressBaseTwo = [NSString stringWithFormat:@"%@%@%@",[self convertToBinary:[groupAddressArray[0] integerValue] padding:5],[self convertToBinary:[groupAddressArray[1] integerValue] padding:3],[self convertToBinary:[groupAddressArray[2] integerValue] padding:8]];
    NSString *groupAddressDecimal = [NSString stringWithFormat:@"%ld",strtol([groupAddressBaseTwo UTF8String], NULL, 2)];

    NSString *message = [NSString stringWithFormat:@"1|%@|%i\0",groupAddressDecimal,(int)(value * 100)];
    
    NSLog(@"%@",message);
    
    NSData *data = [message dataUsingEncoding:NSASCIIStringEncoding];
    [_socket writeData:data withTimeout:10 tag:0];
}

- (NSString *)convertToBinary:(NSInteger)number padding:(int)padding
{
    NSMutableString *str = @"".mutableCopy;
    for(NSInteger numberCopy = number; numberCopy > 0; numberCopy >>= 1)
    {
        [str insertString:((numberCopy & 1) ? @"1" : @"0") atIndex:0];
    }
    NSString *variablePadding = [NSString stringWithFormat:@"%%0%id",padding];
    return [NSString stringWithFormat:variablePadding,str.integerValue];
}

@end

PHP

function convertToBinary($number, $padding) {
    $str = '';
    for ($numberCopy = $number; $numberCopy > 0; $numberCopy >>= 1) {
        $str = (($numberCopy & 1) ? '1' : '0') . $str;
    }
    $variablePadding = sprintf("%%0%dd", $padding);
    return sprintf($variablePadding, intval($str));
}

// Function to generate a KNX command from a group address and a value
function generateKnxCommand($groupAddress, $value) {
    $groupAddressArray = explode('/', $groupAddress);
    
    $groupAddressBaseTwo = convertToBinary($groupAddressArray[0], 5) .
    convertToBinary($groupAddressArray[1], 3) .
    convertToBinary($groupAddressArray[2], 8);
    
    $groupAddressDecimal = bindec($groupAddressBaseTwo);
    
    $message = sprintf("1|%d|%d\0", $groupAddressDecimal, intval($value * 100));
    
    return $message;
}