From what I can see pressure is the only analytical variable that isn’t included on the graph.
Having the pressure tracked will be able to show the impact of negative or positive pressure on a crop.
Makes sense. The data is being calculated, I wouldn’t see why it’s not/shouldn’t be on the graph. I’d like to see that too! Good tip!
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GUESS WHO VOTED!? I did!
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You know I use this device to minimize the swing of relative humidity (relative)? Seeing a vpd number is already there by watching (RH). But I will always take more for the money. 
I been dealing with my first spider mite infestation ever (growing for 2 years). (They liked my (RH).
Neighbor’s clone, I new better.
Just took down and cleaned 4x6 tent and 2.5x2.5 tent, sorry about the highjack of the link.
I’d like to have this ability as well, I’m running a 5’ x 9’ tent with 2 x 750W LEDs & have a 4’x4’ that shares it’s air & exhausts it’s hot air into the 5x9. I just purchased a Pulse One to put in the 4x4 & already have a Pulse Pro in the 5x9. I’d like to see when the pressure shifts on the graph so I know when the exhaust fan in the 4x4 is pulling cool air/ venting hot air into the 5x9 so I can attempt to get both tents dialed in with VDP.
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So I hate to be that guy but…
This is more of a measure of atmospheric pressure. So at sea level you have 1 atmosphere or 101,325 pascals or 101.3 kPA of pressure. This is measuring the same thing as a barometer, which is measured in bars,1 atmosphere = 1.01325 bars. However barometers are commonly displayed in inHg (inches of mercury) in the USA . (29.53 inHg = 100 kPA = 100,000 pascals)
Honestly this is a better measure of weather. I took the past couple hours worth of data and determined that it ranged from 100,395 - 100,459 pascals or 100.3 - 100.4 kPa. This is assuming the sensor is accurate to +/- 1 pascal (accurate to even 1% would be 1000 pascal +/-). The range is so low that the changes in numbers are certainly within the margin of error.
TL:DR - There is little to no effect on pressure from an exhaust fan in a tent. The negative or positive pressure is so incredibly minimal, that it either has no effect or its so little that the sensor isn’t accurate enough for it to be useful data. Additionally it would mostly be a flat line on a graph as “stormy” is around 94.0 kPa and “clear and very dry” is around 104 kPA. (at sea level), these numbers typically do not fluctuate super quickly.
Additionally the CDC lists their negative pressure requirements as 2.5 pascals. So a medical isolation wards is only approx 2.5 pascals of negative pressure. (source: Air | Background | Environmental Guidelines | Guidelines Library | Infection Control | CDC)
If we are gonna change anything, I’d prefer the dash display the VPD to go to more than 1 decimal place cause 1.19 and 1.10 VPD are displayed as 1.1 
Fun fact: Normal pressure @ sea level 101.3 kPa, in Denver it is 83.0 kPa. 
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You bring up good points, but what can be done is using two pulse devices to track a pressure differential. I did a test some time ago. Here’s the graph from it:
- Orange is the sensor inside of a grow tent
- Blue is a sensor outside of a grow tent
- Grey is the difference between the two
You can see the two time periods that i turned on/off the exhaust fan in the tent, the drops into the negatives, and the two series diverge significantly.