How to set multiple MCC DAQ HAT boards together?

[zaippy]

Moin,

I’m trying to follow the Documentation 2.2 to stack my MCC 118 and MCC 134 together.

Now I had such a problem. When I separately use them, they both worked well.  So the hardware is ok. 
 

When I try to stack them together, MCC 134 with address 0 still worked, but MCC 118 with address 1 would be “Addr 1: incorrect response”. I’ve check the EEPROMS every time. 
 

i don’t know how to let MCC 118 work together with 134. 

[Fausto]

Hello @zaippy.

Let me first direct you to some online reference pages.

https://mccdaq.github.io/daqhats/hardware.html#installing-multiple-boards

https://github.com/mccdaq/daqhats

Next, which Raspberry Pi module and Raspbian OS are you using?

In your Raspbian OS, open the Applications menu and select Preferences-->Raspberry PI Configuration.  Select 'Interfaces' and make sure both SPI and I2C are enabled.  If they are enabled, then please use the DAQ Hat Manager to read the EEPROMS or use the following command in a terminal: sudo daqhats_read_eeproms. Afterwards, use the DAQ Hat Manager to read the MCC 118 - make sure to choose the correct address.  If you have a hat board from another company, please remove it before testing.

Remove the address jumpers so that the MCC 118 is at address 0 and make sure our board is the only thing attached. From a terminal, run the command sudo daqhats_read_eeproms. It should find an EEPROM at address 0.  Afterwards, add a jumper to the MCC 134 board to set it to address 1, per the online reference.

Report back with your results and screen captures.

Regards,

Fausto

 

[zaippy]

Moin Fausto,

thanks for your reply.
 

I’m using Pi4 Model B, and OS is Raspberry Pi aarch64 Debian GNU/ Linux 11 (bullseye).

 
Here are my settings:

118 no jumper and 134 one jumper on A0

bottom to top: Pi  118  134

Now the 118 works great, have readings on all channels with 1.748V, and 5V on Channel 0 where I test it with a 5V power bank supplier. 
 

But for 134 things not ok. It has readings on all channels with -243~-244 C. I only connect channel 0-2 with sensors and channel 3 suppose be “Open”. 
 

[Fausto]

Hello @zaippy.

Thank you for the reply and images.  Channel 0 appears to have a thermocouple connection, but channels 1 & 2 are unknown wires.  Those unknown wires appear to be from an additional cold junction connection.  Please connect only supported thermocouple types (J, K, R, S, T, N, E, B) to the input channels.  Test your MCC 134 with only one thermocouple.  If the readings are acceptable, then add a second thermocouple, and so on.  If the readings are bad, then try a different thermocouple before ruling out a damaged MCC 134 board.

Here's a link for you to review, to a TechTip article regarding thermocouples for temperature measurements.

https://www.mccdaq.com/TechTips/Measuring-Thermocouples-with-Raspberry-Pi.aspx

Regards,

Fausto

[zaippy]

39 minutes ago, Fausto said:

Hello @zaippy.

Thank you for the reply and images.  Channel 0 appears to have a thermocouple connection, but channels 1 & 2 are unknown wires.  Those unknown wires appear to be from an additional cold junction connection.  Please connect only supported thermocouple types (J, K, R, S, T, N, E, B) to the input channels.  Test your MCC 134 with only one thermocouple.  If the readings are acceptable, then add a second thermocouple, and so on.  If the readings are bad, then try a different thermocouple before ruling out a damaged MCC 134 board.

Here's a link for you to review, to a TechTip article regarding thermocouples for temperature measurements.

https://www.mccdaq.com/TechTips/Measuring-Thermocouples-with-Raspberry-Pi.aspx

Regards,

Fausto

Thanks for reply.  Well, the wires are fine. They’re just extension of thermocouples. But I still unplug them all as you suggest. 
 

I actually have two 134 boards(I shall name them 134a and 134b). I set them both as jumper A0, which means Address 1. Board 118 on Address 0 as always.  When I use 134a or 134b alone, they both worked fine.

Once I combined 118 and 134a, 134a would come up with around -240 C on all channels even I unplugged all the wires and thermocouples.
 

For 118 and 134b, 134b would show “Open” on all the channels though I connect one thermocouple on Channel 0 (and it works when 134b works alone). 

P.s. I reboot my Pi and check EEPROMS every time.

That’s really weird. If the problem is with my Pi, two 134 boards should have the same “Symptom”. 
 

 

[zaippy]

I have something to add up with. 
 

I did another test by combining 134a and 134b together, where I set 134a Address 0 channel 3 connected and 134b Address 1 channel 0 connected. Reboot and check EEMPROMS. 
 

Then I run the example code “single value read”. I’m asked to select the Address. No matter which Address I choose, I only get reads from Channel 3 (correct temp reads around 20), others left “Open”.
 

Then I switch only their Address, I still only get reads from Channel 3. But this time is Channel 3 “Common Mode”. 

[Fausto]

Hello @zaippy.

Remove all MCC DAQ HAT boards from your Raspberry Pi.  Afterwards, remove all address jumpers from one MCC 134 board and then mount it on your RPi.  Next, please use the DAQ Hat Manager to read the EEPROMS or use the following command in a terminal: sudo daqhats_read_eeproms.  Connect a known good thermocouple, not an extension, to channel 0 and then take some measurement readings.  Afterwards, connect another known good thermocouple, not an extension, to input channel 1 and take some readings.  Repeat these steps again for channels 2&3. 

Regards,

Fausto