Test and Measurement Forum

Lost data on channel

Having problems ? let us know the details here

Lost data on channel

Postby doie » Fri Feb 10, 2012 3:55 pm

Hi guys, A newby at this data logging. We installed a tc-08 unit with 5 thermocouples. Seemed to be running fine up to this morning. The unit wasn't being recognised this morning so I re-installed everything, set-up the channels again (incl the thermocouple types). Problem 1 is that the logger keeps flashing Red/Green even after the set-up is complete and recording. Problem 2 is that channel 1 thermocouple reads crazy - anything from -267C to 175 and then usually ends up going to '*****'.
I checked the thermocouple but it seems OK as far as the connections etc go. I moved it to another channel and it behaves the same but I'm hoping it's something I did as they were only calibrated a couple of weeks ago. Is it something obvious I missed at the re-install maybe? Cold junction channel shows as not installed
doie
Newbie
 
Posts: 0
Joined: Fri Feb 10, 2012 3:44 pm

Re: Lost data on channel

Postby Hitesh » Fri Feb 10, 2012 4:52 pm

Hi Doie,

The red/green light flashing is normal for the TC-08 - the red/green flashing LED indicates the device is connected and reading data.

Are you connecting the device to a laptop? If so, is it plugged into a mains power supply?

If you are using a desktop, are any of the thermocouples touching something that might be able to inject some kind of voltage, or are the thermocouples close to any voltage sources?

Regards,
Hitesh

Technical Specialist
Pico Technology
Hitesh
Site Admin
Site Admin
 
Posts: 2058
Joined: Tue May 31, 2011 3:43 pm
Location: St. Neots, Cambridgeshire

Re: Lost data on channel

Postby doie » Mon Feb 13, 2012 9:22 am

Hello Hitesh,
The logger is connected to a laptop running on mains power. The thermocouples are set-up in an autoclave to meaasure the temperatures at different points so they are going from the logger, through an access port and into the body of the autoclave. All of the readings this morning were OK (reading the ambient temperature of 21C) but when I put all 5 into some warm water to check the responses the problem one went to '*****' again.

As far as I can tell there are no voltage sources close to the thermocouples and they are all going through the same access port.
doie
Newbie
 
Posts: 0
Joined: Fri Feb 10, 2012 3:44 pm

Re: Lost data on channel

Postby Hitesh » Mon Feb 13, 2012 3:03 pm

Hi Doie,

This is likely to be a common mode voltage problem.

Please try taking the thermocouple out from channel 1 and plugging it into otherfree ports and see if the issue occurs again.

Also, ensure that the thermocouple tips are not touching anything else.

Regards,
Hitesh

Technical Specialist
Pico Technology
Hitesh
Site Admin
Site Admin
 
Posts: 2058
Joined: Tue May 31, 2011 3:43 pm
Location: St. Neots, Cambridgeshire

Re: Lost data on channel

Postby doie » Mon Feb 13, 2012 5:12 pm

Hi Hitesh,
I removed the thermocouples from the autocolave and re-seated them back in. During this I removed them from the logger completely and re-inserted them again. I set-up the logger in a new position and re-started everything again. Now it seems to be working OK. I don't know if it was the logger connection or maybe in its original position it was picking up interference from something I couldn't see in the autoclave.
For now i don't care as long as I can record with it again. Thanks for the support.

Damien
doie
Newbie
 
Posts: 0
Joined: Fri Feb 10, 2012 3:44 pm

Re: Lost data on channel

Postby DenAtRubberatkins » Thu May 24, 2012 6:41 am

Hi , If you are using a USB logger and you get ***** in the display then unplug the logger and replug it in. Also if you are using a laptop you may need to ground it properly to get accurate readings, be sure to ask an electrician for advice on where to connect to the ground.

Den.
DenAtRubberatkins
Newbie
 
Posts: 0
Joined: Thu May 24, 2012 6:18 am


Return to Getting Started

Who is online

Users browsing this forum: No registered users and 0 guests