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PXIe-1082 I2C SMBUS protocol temperature monitoring

 Hi,

 

we are trying to access the temperature sensor on the PXIe-1082 backplane ( SMBCLK and SMBDAT lines) but we can not find any software protocol informations for this device.

The only information we have is from manual "373001a.pdf" page 14: "There is a temperature monitoring device at slave address 5CH".

The question is, how to get the temperature data from this address ?

 

Also we wonder what voltages needs to be applied to the backplane in order to make the SMBUS working.

 

Thanks.

 

Martin

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Hi Mike,

 

I found a community example that can remotely read from the onboard temperature sensor:

https://forums.ni.com/t5/Example-Code/PXIe-Health-Monitor/ta-p/3513409

 

I would look into how they reference the sensor and use it to verify the method used in your program. 

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Hi, thank you. Sadly I do not have Labview and I have no idea how it works.... I can not reverse engineer this application. There should be some informations somewhere else....

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I have connected a I2C Master Device to the SMBUS and read the data from address 0x5C with 8bit addressing.

 

The result is :

> SMBus Read,PEC = Off, Address = 0x5C, Register Index = 0, Read 32 bytes, Delay = 0
OK
< 14 4E 61 74 69 6F 6E 61 6C 20 49 6E 73 74 72 75 6D 65 6E 74 73 73 73 73 73 73 73 73 73 73 73 73

 

This seems to be an ASCI string that converts to

"National Instrumentssssssssssss"

 

Okay. This is not a temperature value....

 

The Bus Scan gives the following:

Slave found. 8 bit address = 0x5A; 7 bit address = 0x2D Write
Slave found. 8 bit address = 0x5B; 7 bit address = 0x2D Read
Slave found. 8 bit address = 0x5C; 7 bit address = 0x2E Write

 

Address 0x5A and 0x5B both read "0xF1, 0x71" as static value. Not sure what that is:

 

> SMBus Read,PEC = Off, Address = 0x5A, Register Index = 0, Read 2 bytes, Delay = 0
OK
< F1 71
> SMBus Read,PEC = Off, Address = 0x5B, Register Index = 0, Read 2 bytes, Delay = 0
OK
< F1 71

 

 

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