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CR800 and CR1000 - adding a pressure switch?


DayFarms Aug 27, 2010 12:52 PM

I'm trying to add a pressure switch to CR800 and CR1000 loggers. I want them to take data when the pressure of the irrigation drip tape reaches 10 psi. How do I add this into the scenario/program? Also, how do I make sure that the logger will continue to take data even if the pressure goes above 10 psi? Any advice would be greatly appreciated.


IslandMan Aug 27, 2010 08:12 PM

This should give you an example of how to accomplish this. The Test table will only write data when the Variable RecData is True.

'CR1000 Series Datalogger
'Declare Public Variables
Public Pressure
Public PTemp
Public RecData As Boolean

'Define Data Tables
DataTable (Test,RecData,1000)
Sample (1,PTemp,FP2)
EndTable


'Main Program
BeginProg

RecData = False

Scan (1,Sec,0,0)

PanelTemp (PTemp,250)
'Measure the Pressure Sensor
VoltSe (Pressure,1,mV5000,1,1,0,250,1.0,0)
If Pressure >= 10 Then
RecData = True
Else
RecData = False
EndIf
CallTable Test
NextScan
EndProg


Sam Aug 29, 2010 07:52 PM

This would also be a good time to use the "DataInterval" table modifier.

Public PTemp
Public Pressure

DataTable (Test,1,1000)
DataInterval (0,5,Sec,10) 'can use to control write interval
DataEvent (5,Pressure>=10,Pressure<10,5) 'will record 5 records (in this case 25 seconds of data) prior to Pressure>=10 and 5 records after Pressure falls below 10. Makes "bookending" event easy.
Sample (1,PTemp,FP2)
EndTable

BeginProg
Scan (1,Sec,0,0)
PanelTemp (PTemp,250)
'Measure the Pressure Sensor
VoltSe (Pressure,1,mV5000,1,1,0,250,1.0,0)
CallTable Test
NextScan
EndProg


IslandMan Aug 30, 2010 09:29 AM

I learn something new every day reading this forum. Thanks Sam


DayFarms Aug 30, 2010 11:50 AM

Thanks so much for the help!Now here's my next question. How would I physically wire the pressure switch into the data logger? The pressure switch is an Irrometer that reads up to 15 psi and the data loggers I am using are CR800 and CR1000. I am very new at this so the more specific you can get the better. Thanks again.


IslandMan Aug 30, 2010 12:26 PM

Can you be a little more specific with a mfg and model number of the Irrometer so I can look up the manual?


DayFarms Aug 30, 2010 12:41 PM

The gauge is made by Irrometer, it is a 0-15 psi sealed gauge w/DC switch closed past setting #22. The item number is 1-7-15-ADS.


IslandMan Aug 30, 2010 05:21 PM

I couldn't find anything very specific about the switch but I'm assuming the DC means it switches a DC load vs AC.

I would connect one side of the switch to C1 on the logger and the other side to the 5V terminal. Use this program and see if it gives you a 0 (zero) when the switch is open and a 1 (one) when the switch is closed in the Irrometer variable.

Public PTemp
Public Pressure
Public Irrometer

DataTable (Test,1,1000)
DataInterval (0,5,Sec,10) 'can use to control write interval
DataEvent (5,Pressure>=10,Pressure<10,5) 'will record 5 records (in this case 25 seconds of data) prior to Pressure>=10 and 5 records after Pressure falls below 10. Makes "bookending" event easy.
Sample (1,PTemp,FP2)
EndTable

BeginProg
Scan (1,Sec,0,0)
PanelTemp (PTemp,250)

****************************************
'Measure the Pressure Sensor
PortGet (Irrometer,1 )
****************************************

CallTable Test
NextScan
EndProg


DayFarms Aug 30, 2010 07:02 PM

Thanks alot. I'll give that a try and let you know what I find. I was also wondering if I set the pressure switch to collect data at 10 psi, would it collect one point of data and then stop or would it continuously collect data until the pressure reaches below 10 psi? I want it to continuously collect, is there a specific way to make it do this or will it continuously collect already?


IslandMan Aug 30, 2010 07:22 PM

If you changed my program to this it would record as long as the Irrometer value = 1:
Scan (1,Sec,0,0)

PanelTemp (PTemp,250)

'Measure the Pressure Sensor
PortGet (Irrometer,1 )

If Irrometer = 1 Then
RecData = True
ElseIf Irrometer = 0
RecData = False
EndIf

CallTable Test
NextScan
EndProg

If you change this line in Sam's program it will work the same way:
DataEvent (5,Irrometer=1,Irrometer=0,5) 'will record 5 records (in this case 25 seconds of data) prior to Pressure>=10 and 5 records after Pressure falls below 10. Makes "bookending" event easy.


DayFarms Aug 31, 2010 08:28 PM

Thanks for all of your help. So far the pressure switch is working fine. I appreciate the program examples, they helped out a ton.

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