Voltage to Force Measurements

I have built a center of pressure circuit connected to a deconstructed weight scale (pictured) I've been able to record voltage signals on the board by using an NI

cDAQ9178 and MatLab (code pictured below) I'm trying to turn voltage signals from the scale into an x y plot of force measurements to track the sway of a person. I've researched extensively but I can't seem to find the code for that or even a place to start.

>> devices = daq.getDevices
s = daq.createSession('ni');
s.Rate=8000;
s.DurationInSeconds = 10;

devices = 

Data acquisition devices:

index Vendor Device ID              Description              
----- ------ --------- --------------------------------------
1     ni     cDAQ1Mod1 National Instruments(TM) NI 9215 (BNC)
2     ni     cDAQ1Mod2 National Instruments(TM) NI 9215 (BNC)
3     ni     cDAQ1Mod3 National Instruments(TM) NI 9215 (BNC)
4     ni     cDAQ1Mod4 National Instruments(TM) NI 9215 (BNC)
5     ni     cDAQ1Mod5 National Instruments(TM) NI 9224


>> ch = addAnalogInputChannel(s,'cDAQ1Mod4',0,'Voltage');
ch = addAnalogInputChannel(s,'cDAQ1Mod4',1,'Voltage');
ch = addAnalogInputChannel(s,'cDAQ1Mod4',2,'Voltage');
ch = addAnalogInputChannel(s,'cDAQ1Mod4',3,'Voltage');

>> xlabel('Time (secs)');
ylabel('Voltage');
>> data=s.startForeground();
plot(data)