Hello,
I'm hoping someone can help me out with this problem. I have a CR1000 with 16 Type E thermocouples connected (single ended type measurement). I am trying to program it using Shortcut but it will only allow me to add 8 thermocouples (it assumes they are connected for a differential type measurement).
Is it possible to specify TCSe in shortcut?
Thanks in advance,
Dan.
It doesn't appear that you can specify 16, Cut/Paste your program here and I'll modify it for you.
Hello,
since my question is also referred to thermocouples and the instruction TCSe I continue in this session.
I have a solid state multiplexer AM25T plugged to a CR5000, and 50 thermocouples type T that I would like to use in single-ended mode. Shortcut doesn't allow me to do it (max is 25), and I didn't manage to apply the instructions provided in the examples on the AM25T manual for single-ended thermocouples measurements cause they are referred to other dataloggers (CR10, 21X..), older than CR5000 I guess.
Then the first question is:
- Could you provide me an example of instructions to write for measuring thermocouples in single-ended mode, with an AM25T and a CR5000 or CR1000?
I also tried to use the instruction TCSe directly on the CR5000 and it works fine, but since I haven't so many free channels on the datalogger I would like to use a multiplexer AM16/32:
- Is it possible to use TCSe instruction in the multiplexer?I tried without success.
Thanks in advance,
Francesco
Generally as a rule we try to encourage users not so make singel ended thermocouple measurements especially with multiplexers. The reason is that it is very easy to introduce an offset on the common ground reference line used for SE measurements, especially with long cables. For thermocoules an offset of only 1 mV will cause an error of ~20 deg C (depends on TC type), which is unacceptable to most users.
If you are aware of the problem you can of course make the measurement but you have to drive the mulitplexer manually.
The program below is a quick conversion of the CR10X program - not tested though. Using an AM16/32 is similar but the program will need extra delays due to the mechanical relays, you need to work out how to reference the thermocouples and you can get worse errors due to temperature gradients.
'CR5000 Series Datalogger
'Date written: 20/07/2011
Public i1
Public RefTemp_C
Public TC(50)
BeginProg
Scan(10,Sec, 3, 0)
PortSet(2, 1)
BrFull(RefTemp_C, 1,mV50, 1, VX1, 1, 1200, True, True, 0, _50Hz, -0.001, 0.09707)
RefTemp_C = 10.025*(RefTemp_C/(1.0-RefTemp_C))
PRT(RefTemp_C,1,RefTemp_C,1,0)
i1=1
SubScan (0,uSec,25)
PulsePort(1,1000)
PulsePort(1,1000)
TCSe(TC(i1),2,mV20C,1,TypeT,RefTemp_C,False,0,_50Hz,1,0)
i1=i1+2
NextSubScan
PortSet(2, 0)
NextScan
EndProg