Test and Measurement Forum

PT-104 temperature jumps

Post any questions about our serial port products

PT-104 temperature jumps

Postby bickerstaffe » Wed Jul 15, 2009 10:00 am

I'm using a PT-104 with two PT100 sensors in a water bath. I also have some thermocouples in the bath. The water bath temperature is controlled so that it is at 30C, then 35C, 40C, 45C, waiting for around 1/2 hour at each temperature.

The problem is that when changing from one temperature to a higher temperature the PT104 readings seem to have got 'stuck' at the lower temperature. eg the water bath takes ~1 minute to heat up from 30C to 35C, but 10 minutes later the PT100s are both still reading 30C. Then suddenly, they both jump to reading 35C, and appear to be correct at that point.

Is it a software bug? I'm using Picolog 5.20.6.
bickerstaffe
Active User
Active User
 
Posts: 6
Joined: Mon Jun 29, 2009 12:15 pm

update

Postby bickerstaffe » Wed Jul 15, 2009 12:31 pm

Looking more closely at my logged data, it is apparent that the PT104 is failing to update the PT100 values for periods of up to 10 or 20 minutes. (This during a 6 hour run).

What is the cause of Picolog failing to update values?
bickerstaffe
Active User
Active User
 
Posts: 6
Joined: Mon Jun 29, 2009 12:15 pm

Postby ziko » Wed Jul 15, 2009 1:58 pm

Hi this is a bit of a strange one.

Is there any programmes running in the background that could cause conflict, also are you using a serial port or a USB to serial converter?

KInd regards
Ziko

Technical Specialist
ziko
Zen Master
Zen Master
 
Posts: 1705
Joined: Fri Dec 01, 2006 10:03 am
Location: St Neots

Postby bickerstaffe » Wed Jul 15, 2009 2:34 pm

I'm connecting the PT104 directly to a serial port on my laptop. The computer was running only a few programs - Outlook, Google Chrome, and normal background processes (antivirus etc).

Having analysed my data further, I've found other problems. The logging interval is 1 second, but the time in seconds in the datafile is discontinuous. There are jumps where no data is recorded, jumps where zeros are recorded, and large swathes of data with the same time repeated.

I've attached a zip of the csv file saved from the spreadsheet view. The raw data file is too large to attach, even when zipped.
Attachments
raw data.zip
(209.24 KiB) Downloaded 209 times
bickerstaffe
Active User
Active User
 
Posts: 6
Joined: Mon Jun 29, 2009 12:15 pm

Postby ziko » Fri Jul 17, 2009 10:52 am

HI,

I want to try and recreate your problem, could you tell me what version of the software you are using?

Also could you try slightly slower sampling and stopping any applications running in the background to see if it makes a difference.

Kind regards

Ziko
Ziko

Technical Specialist
ziko
Zen Master
Zen Master
 
Posts: 1705
Joined: Fri Dec 01, 2006 10:03 am
Location: St Neots


Return to Serial Port Products

Who is online

Users browsing this forum: No registered users and 0 guests