here the program created via shortcut to read AC current transformers.
I was trying to have measure but have for now just NAN value, and just see something that I think it could be the problem. Just look at the program (created with shortcut), it seem that "amperage" is filled with "CS11Array(4)" which, if I'm not wrong, contain 4 values, but one is recorded ; is there not a msitake here ?
Could it be the NAN ?
'CR800 Series 'Created by Short Cut (4.4) 'Declare Variables and Units Dim CS11Array(7) Public BattV Public PTemp_C Public Amperage Units BattV=Volts Units PTemp_C=Deg C Units Amperage=A 'Define Data Tables DataTable(Table1,True,-1) DataInterval(0,1,Min,10) Sample(1,Amperage,FP2) Average(1,Amperage,FP2,False) EndTable 'Define Data Tables DataTable(Table2,True,-1) DataInterval(0,10,Min,10) Minimum(1,BattV,FP2,False,False) EndTable 'Main Program BeginProg 'Main Scan Scan(5,Sec,1,0) 'Default CR800 Datalogger Battery Voltage measurement 'BattV' Battery(BattV) 'Default CR800 Datalogger Wiring Panel Temperature measurement 'PTemp_C' PanelTemp(PTemp_C,_50Hz) 'CS11 Current Transformer measurement '5' ACPower(CS11Array(),1,50,1,1,6.6,2,0.2,50,1) Amperage=CS11Array(4) 'Call Data Tables and Store Data CallTable Table2 NextScan EndProg
The ACPower instruction returns several values. The fourth value is the amperage. Program code looks correct to me.
Check your sensor wiring.
Of course, you're right, "CS11Array(4)" donesn't mean four values but the fourth value, my bad.
Sensor is not the CS11 (CR8459) sensor but a similar model CR8448, same model but different scale of measure (see manufacturer doc here).
It just have 2 wires (black / white) and a shield. Shortcut tells me to plug white on a SE channel and the black on the GND. I tried the reverse side in the case the manufacturer changed his color code during years, but same results NaN.
Reading sensor directly with a voltmeter give me, in DC, something about 40 mVdc and, in AC, something about 7 Vac.
Is the ACPower instruction reads AC or DC voltage ? Since you have to enter a frequencie in the instruction, maybe it's AC voltage ? But I'm not sure.
You need to put a burden resistor between the two wires to change the output from microamps to millivolts. The resistance R shown on the manufacturer document is not inside the transducer. You have to add it. Pick a resistor value that will create a peak voltage less than the 5 volt max of the CR800.
A CS11 has a burden resistor in the cable wiring.
Thanks for your instruction, I understand much better the situation. Here is my (new) installation :
Plugged the CR8448 with a resistor of 6,5 kohm in parallel between 1H and Mass, which with the DCR of 134 ohm of the transducer, make a voltage divider bridge of (134*(134+6800)) = 0,019.
So, in theory, for a reading voltage of 6,7 Vac ont the transducer, I should have something about 0,13 Vac on the CR800, that correspond to approx. 0,25 A of current on the electrique circuit I'm measuring.
I modified the program to read the first four value (power, frequency, voltage and amperage). And here we go !
When the electric circuit is off, here the measures :
Power : NAN
Freq : NAN
Volt : 0,9
Amp : 0,38
When the electric circuit is on (and consomes approx 0,25A), the measures is :
Power : NAN
Freq : 50,02
Volt : NAN
Amp : 0,34
In conclusion, only frequency seem to works correctly. I'm in france, so it's 50 Hz electrical network.
Ok I tried harder, and here my new instruction ACPower :
This time, I'm using 2 transducers, the first on SE1 (1H) dedicated to voltage measure and the second, on SE2 (1L) for current. In both case, second wire is connected to Mass.
I succeeded to read 240 volts on a first installation to measure, and it droped on 140 volt on a second installation... But both are connected to public electrical network.
Current is incorrect, even if value are near to zero when electricity is off.
Only frequency still clearly read correctly.
I'm beaten by this problematic ...
Hi again, problem seem to escape to me, I tried things, but things goes wrong.
1. Here a schematics with my installation, to understand much better and much faster.
2. And here my actual program :
'CR800 Series 'Created by Short Cut (4.4) 'Declare Variables and Units Dim CS11Array(7) Public BattV Public PTemp_C Public Power Public Freq Public Voltage Public Amperage Public ac5 Public ac6 Public ac7 Public bat Units BattV=Volts Units PTemp_C=Deg C Units Power=W Units Freq=Hz Units Voltage=V Units Amperage=A Units ac5=mV Units ac6=mV Units ac7=mV Units bat=mV 'Define Data Tables DataTable(elec,True,-1) DataInterval(0,1,Min,10) Sample(1,Power,IEEE4) Average(1,Power,IEEE4,False) Sample(1,Freq,IEEE4) Average(1,Freq,IEEE4,False) Sample(1,Voltage,IEEE4) Average(1,Voltage,IEEE4,False) Sample(1,Amperage,IEEE4) Average(1,Amperage,IEEE4,False) Average(1,bat,IEEE4,False) Sample(1,bat,IEEE4) EndTable 'Define Data Tables DataTable(soh,True,-1) DataInterval(0,10,Min,10) Minimum(1,BattV,FP2,False,False) EndTable 'Main Program BeginProg 'Main Scan Scan(10,Sec,2,0) 'Default CR800 Datalogger Battery Voltage measurement 'BattV' Battery(BattV) 'Default CR800 Datalogger Wiring Panel Temperature measurement 'PTemp_C' PanelTemp(PTemp_C,_50Hz) 'CS11 Current Transformer measurement '5' ACPower (CS11Array,1,50,1,0.345345,240,2,0.045045,15,1) Power=CS11Array(1) Freq=CS11Array(2) Voltage=CS11Array(3) Amperage=CS11Array(4) ac5=CS11Array(5) ac6=CS11Array(6) ac7=CS11Array(7) 'Generic Differential Voltage measurements 'bat' VoltDiff(bat,1,mV5000,2,True,0,_50Hz,1,0) 'Call Data Tables and Store Data CallTable elec CallTable soh NextScan SlowSequence 'synchronize on the GPRSrouter Scan (10,Min,3,0) NetworkTimeProtocol ("192.168.1.1",0,1000) EndSequence NextScan EndProg
3. Then a sample of my readings :
[...](when 230Vac is on)
4. Then finally some measures in a graph :
Frequency is no longer read (or rarely). Voltage & Current are incorrect, even if it drop to zero when I cut off the 230Vac (several time in a day). And I put a VoltDiff instruction to read battery tension (with a ratio of 3.5, so 3.4 Vdc read is 12Vdc "true") and even this measure is totally wrong, and random.
And so, I don't understand.
Please confirm if you are using the CR8448-1000 ot the CR8448-2000. Different sub models would be different multipliers.
A NAN analog measurement will happen if the signal is higher voltage than the input range. Maximum input range on the CR800 is +-5VDC. Smaller ranges as seen in the VoltDiff instruction are available. Voltage on an analog channel compared to Earth(on the datalogger) should not exceed 5V either.
The ACPower() instruction selects an input range based on the MultI and MaxIrms values used. Your latest program is using default values used for transducers with 0.333Vac output. The multiplier is in units of Amps/millivolt
For CR8448-2000 with 6.7 kOhm burden resistor:
V= (1 amp * 6700)/2046 = 3.275 Volts at 1 amp of current
2 amps would overvoltage the channel. I believe you are using too high a resistance value for the burden resistor. It limits the amount of current that can be sensed.
thanks for your answer,
My transducer is CR8448-2500-N.
In order to follow your indication, and want to measure until 10 amps, I change my burden R on the CR800 to use 620 ohm. With your calculation, I must have something about 2470 mV ; I would passthe CR800 on 2500 mV scale but I just realize that with ACPower instruction, you can't choose the input scale.
I just looked in dev config utility and measures still 'NaN' with new burden R.
And measuring manually the CR8448 in open circuit give me approx 30 mV, for 0,12 A measured with an ammeter on the 230 Vac.
I've used an oscilloscope to read transducer with certitude.
So with a measured current of 90 mA stable (with two different models of clamp ammeter), a transducer CR8448-2500-N produce a potential of 20 mV peak-to-peak at 50Hz.
But reading the CS11 manual, there are several resistances, including the burden resistance, that could be a part of my problem ; I think I have to reproduce a CS11 and adapt the resistance value, to obtain a good measure. Could you please indicate me what the resistance value on the diagram (page 6 of the manual) :
I'm still in need of information about the resistance of the CS11 if someone got them, because I'm stuck in this problem that I currently can't solve, in spite of my efforts.