control temperature

[steveawe]

Hi ya

I have created an experiment that uses a AWG to measure strain on a
cantilever.  I therefore have created a labview programme that reads
voltages from a photodiodes on a BNC 2110, this then writes it to a
spreadsheet file. 
I am at present running a temperature control VI that controls the temp
controller and this heats or cools the AWG so I can manually set the
temp to move the wavelengths to make the power on the photodiodes read a
linier power.
I.e
Photodiode 1 - @ 20deg c is 1.2 V
Photodiode 1 - @ 20deg c is .2 v

If I heat the AWG to 36.8 deg C I can move the wavelengths so I can get
0.5v on Both photodiodes.

I however need to temperature stabilise the AWG so that the wavelengths
shift across as the temp increases.

How do I measure the voltages on the photodiodes and increase/decrease
the power on the temp controller to heat/cool the AWG so it reads the
voltages at real time and sets the current to shift the wavelength?

I.e

Photodiode 1 - @ 20deg c is 1.2 V
Photodiode 2 - @ 20deg c is 0.2 v
Provide current to temp controller -
Read back voltages
Photodiode 1 - @ 25deg c is 1.0 V
Photodiode 2 - @ 25deg c is 0.3 v
Provide current to temp controller -
Read back voltages
Photodiode 1 - @ 30deg c is 0.7 V
Photodiode 2 - @ 30deg c is 0.45 v
Read back voltages
Photodiode 1 - @ 36.8deg c is 0.5 V
Photodiode 2- @ 36.8deg c is 0.5 v

Photodiodes now both linear keep it at this level,
If
Photodiode 1 - @ 40deg c is 0.3 V
Photodiode 2 - @ 40deg c is 0.6 v
Cool
If
Photodiode 1 - @ 36deg c is 0.3 V
Photodiode 2 @ 36deg c is 0.6 v
Heat

[Tom O]

To keep this thread up to date, Steve has been in contact with us directly through technical support.

Steve was looking for some code to help him design the algorithm to control heating & cooling of the AWG, and I am working with him on the issue now.