Created Date: May 01,2019

Created by: skyfox

I have two brand new BRX-06RTD cards. one card is configured to Fail High and the other card is configured to fail low.

Temp scaling for both cards are from from -200 Deg. C to 850 C.

High failure works fine on both cards.

Low failure does not and shows 325.deg C instead of -200 Deg. C. No error bits. What could be the issue and how do I fix this. I really need them to fail low at -200 Deg. C.

Thanks.

UPDATE:

Interestingly enough. I also have two new BRX-06RTD cards attached to my test bed BRX36 PLC. However, neither one of them have 24VDC applied to them. They are just sitting there attached to the CPU and without any RTD's attached to them. They are configured to fail High and low like the actual system's PLC/RTD's. In the test bed, both High and low failure card inputs show 325 Deg. C in this scenario. So, I went back and confirmed that 24vdc is present at each RTD card on the actual system. What is happening here? Failure low or high should follow the failure. i.e. RTD not plugged in, Fuse blown to the input card, etc, etc. My test bed shows the error bits (as it should) , where as the actual system has no error bit set and still shows an invalid low value than what it was configured for. Puzzled amd concerned.But more concerned than puzzled.

Created Date: May 01,2019

Created by: mls061

We see this with our modules here too. When configured for low side burnout, with no probe attached, the raw (WX) value we see is 0 but it should be the low range of the configured probe type. BTW, t he value of 325 you 're seeing is the midpoint of your scaled range (-200 to 850).

There's also a problem with the burnout bits being ON for channels that are disabled. I'm not sure if these issues are related, regardless, w e 've contacted the manufacturer about getting both of there issues resolved. Stay tuned.

Created Date: May 01,2019

Created by: franji1

Since the Error Bits are tied to X's, make sure you are looking at the right set of X's on your actual system. Maybe they "moved " because (for example), your test bed is a BX-18 and your actual is BX-36?

If you have Designer 2.5.2, the I/O System View should show the error(s) correctly (Designer 2.3 did not properly report the Error Bits).

Created Date: May 01,2019

Created by: BobO

Since the Error Bits are tied to X's, make sure you are looking at the right set of X's on your actual system. Maybe they "moved " because (for example), your test bed is a BX-18 and your actual is BX-36?

If you have Designer 2.5.2, the I/O System View should show the error(s) correctly (Designer 2.3 did not properly report the Error Bits).

This could be an issue too, but the RTD module doesn't appear to be outputting the correct channel value for a low side failure. This is completely independent of the CPU's and DmD's error reporting.

Created Date: May 02,2019

Created by: skyfox

Thank you all for your feedback. Both actual system and my test bed hardware are identical. BRX36 CPU's. Please see attached pic as it illustrates what is happening.

I have 8 RTD cards that are doing the same thing. Zero degrees is a balmy temperature when one is dealing with Liquid Nitrogen. I have this sick feeling in my stomach that these cards might not read negative temperatures because of this low end failure behavior. If that is the case, come Monday, I might be looking for new employment as it was me who recommended that we go with the BRX platform. Can someone confirm that these RTD cards are capable of reading temperatures as low as -190C? I can live with -180. If that is the case, I can temporarily live with failing the cards in high mode (broken/disconnected sensor) and interpreting the failure as -200. Hopefully I will get to test this with LN2 on Friday and see if these actually read subzero temperatures.

Edit: On attached pic, item 1, disregard the 1st two columns. Last two columns illustrate a Failed Low condition.

Created Date: May 02,2019

Created by: BobO

Thank you all for your feedback. Both actual system and my test bed hardware are identical. BRX36 CPU's. Please see attached pic as it illustrates what is happening.

I have 8 RTD cards that are doing the same thing. Zero degrees is a balmy temperature when one is dealing with Liquid Nitrogen. I have this sick feeling in my stomach that these cards might not read negative temperatures because of this low end failure behavior. If that is the case, come Monday, I might be looking for new employment as it was me who recommended that we go with the BRX platform. Can someone confirm that these RTD cards are capable of reading temperatures as low as -190C? I can live with -180. If that is the case, I can temporarily live with failing the cards in high mode (broken/disconnected sensor) and interpreting the failure as -200. Hopefully I will get to test this with LN2 on Friday and see if these actually read subzero temperatures.

Edit: On attached pic, item 1, disregard the 1st two columns. Last two columns illustrate a Failed Low condition.

I doubt negative temperature matters. My (admittedly uneducated) guess is that it is a simple firmware bug where rather than emitting -32768 for a low side failure, they are emitting 0. In addition to using a high side failure, you can also check the X bit associated with the channel failure.

Since it is likely a firmware bug, I’m sure the vendor will be able to get this worked out quickly.

Created Date: May 02,2019

Created by: Do-more PE

I doubt negative temperature matters. My (admittedly uneducated) guess is that it is a simple firmware bug where rather than emitting -32768 for a low side failure, they are emitting 0. In addition to using a high side failure, you can also check the X bit associated with the channel failure.

Since it is likely a firmware bug, I'm sure the vendor will be able to get this worked out quickly.

Edit: Just got an update. Stay tuned for more information.

Created Date: May 07,2019

Created by: TheGreatMarklar

We found an issue with the module firmware. Unfortunately this is not going to be able to be updated in the field. Please get with our Returns Department to return the modules that you have and we will get you new modules as soon as we get them back from the manufacturer.

Is there a general need to replace the RTD modules, or only if my application is affected?