adccommunitymod (AutomationDirect) asked a question.
F0-04THM thermocouple module
Created Date: July 06,2004
Created By: Matt24
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I have a DL06 with a F0-04THm module in in and i cannot get it to work properly. I have tried the sample programs and i get real high tempture readings (200+ degrees) for a freezer. I have no idea what I am doing wrong.
Created Date: July 06,2004
Created by: Matt24
I have a DL06 with a F0-04THm module in in and i cannot get it to work properly. I have tried the sample programs and i get real high tempture readings (200+ degrees) for a freezer. I have no idea what I am doing wrong.
Created Date: July 06,2004
Created by: FACTSTech
Are you reading 200 degrees or 20.0 degrees? Note that value returned by the F0-04THM has one implied decimal place so a value of 200 represents 20.0.
Created Date: July 06,2004
Created by: Matt24
the number that i see in the v memory location is 2085. The freezer has a digital gauge reading -80 degrees C.
Created Date: July 06,2004
Created by: FACTSTech
Are you displaying the data value with a DirectSoft DataView window? If yes which display format are you using? If no how are you viewing the data?
What are the values in the seven configuration registers (note which display format is used if viewing these values in DataView)?
What THM type do you have connected?
Which color wires are connected to which terminals?
Is the data changing or does it always show 2085?
If you short CH+ to CH- with a piece of copper wire, what reading do you get (it should be ambient temperature of the F0-04THM module)?
Created Date: July 06,2004
Created by: Matt24
I am using the data view window in BCD/Hex format. I am using the sample program #2 from the manual
I am using The type K thermocouple.
The output number is changing slightly between 2083-2087. i have the red wire to
CH+ and the white wire to CH-.
Created Date: July 06,2004
Created by: Rday
You have the polarity reversed. Red almost always goes to -.
If you have a Red and a White wire your TC is a J type. A type K has a Red and Yellow. Take a look at this link. http://www.omega.com/techref/thermcolorcodes.html
Created Date: July 06,2004
Created by: WilTech
If you are reading subzero Temps - like a freezer - you might consider using a Type T thermocouple (Blue wire +, Red wire -). They work better for below-zero applications.
Created Date: July 07,2004
Created by: Matt24
I have wired the thermocouple myself. I bought a spool of thermocouple wire, and that is what I am using.
Created Date: July 07,2004
Created by: FACTSTech
Have you reversed the connection? The red wire should be on the minus (CH-) terminal. Did the readings change?
Can you verify that your THM wire is type K (should have a red wire and a yellow wire)?
Did you weld the two THM wires together to make the thermocouple junction or is the juntion made some other way?
Created Date: July 07,2004
Created by: C R Williams
Matt24: If you bought a spool of thermocouple wire complete and ready with plastic covered wires what you may well have is thermocouple extension wire. This is similar to, but not the same as, 'real ' thermocouple wire. It sure doesn't explain the current problem, but it might become an accuracy issue once this problem is solved.
I also assume that you know you can't use ordinary copper wire to hook up thermocouples - that's what the extension wire is for.
Sorry if you already know this.