Objective C newbie, one method can change UI elements, others can not - objective-c

Question

thanks in advance for any input. I have been trying to write a program that interprets a serial command into text change in a label. I can change the label text easily with an Action attached to a button, but for some reason all my attempts at changing the label text outside that button action result in nothing being changed.
// MasterViewController.m
//
// Created by Daniel Payne on 2/28/15.
// Copyright (c) 2015 Daniel Payne. All rights reserved.
//
#import "MasterViewController.h"
#interface MasterViewController ()
#property (strong) IBOutlet NSTextField *score;
#property (nonatomic, strong) ORSSerialPort *serialPort;
#property (nonatomic, strong) MasterViewController *masterView;
#end
static MasterViewController *serialPortHelper = nil;
void connectPort(void) {
ORSSerialPort *serialPort = [ORSSerialPort serialPortWithPath:#"/dev/tty.usbmodem1411"];
serialPortHelper = [[MasterViewController alloc] init];
serialPortHelper.serialPort = serialPort;
serialPort.delegate = serialPortHelper;
serialPort.baudRate = #9600;
NSLog(#"port open");
[serialPort open];
}
int main(int argc, const char * argv[]) {
connectPort();
return NSApplicationMain(argc, argv);
}
#implementation MasterViewController
- (IBAction)pushButton:(id)sender {
[self.score setStringValue:#"1"]; //works
}
- (void)viewDidLoad {
[super viewDidLoad];
}
-(void)awakeFromNib
{
NSLog(#"View controller instance with view: %#", self.view);
}
- (void)serialPort:(ORSSerialPort *)serialPort didReceiveData:(NSData *)data
{
NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
if ([string rangeOfString:#"g"].location == NSNotFound) {
NSLog(#"no goal");
} else {
[self.score setStringValue:#"1"]; //does not work
NSLog(#"GOOOOAL");
}
}
- (void)serialPortWasRemovedFromSystem:(ORSSerialPort *)serialPort
{
self.serialPort = nil;
}
- (void)serialPort:(ORSSerialPort *)serialPort didEncounterError:(NSError *)error
{
NSLog(#"%s %# %#", __PRETTY_FUNCTION__, serialPort, error);
}
- (void)serialPortWasOpened:(ORSSerialPort *)serialPort
{
NSLog(#"Serial port %s was opened", [serialPort.name UTF8String]);
}
#end

Answer 1

The instance of MasterViewController that is listening to your serial port is not the same one that you are seeing on screen.
You create a new one and assign it to a static variable - this is not the same one you have loaded from a nib with all its outlets connected.
Log self in both methods to confirm.