VREF Error

Luke Ricker 5 years ago in Expansion modules / XA2, XS2 updated 5 years ago 3
Hello all,

First of all, I'm very happy to see this online community, We have been needing an IQAN development/troubleshooting/idea-sharing place for a while, and I'm happy to be a part of it,

My question is:
What exactly does a "VREF Error" message mean when it is not associated with an input channel? We have a MD3 connected to 2 XA2 modules. Intermittently, a system message will display that reads: "XA2.0 VREF Error  2.2V"
The system runs on 24VDC.
What conditions could possibly cause the VREF on an XA2 module to dip so low? Again, the VREF error is not indicated as being associated with any particular input -- just an XA2 module. If the system/battery voltage drops low, does the reference voltage regulator have trouble maintaining 5 volts? Wouldn't the system just shut off before that happens?
Has anyone experienced this before?

Under review
Hi Luke, welcome to the IQAN forum,

Each XA2 montiors its ownVREF, and will report an error if it drops <4.75 V.
The error will generate a popup on the MD3 saying VREF error. Also, the chanel status on the VIN:s on this XA2 will be VREF error, but only if these VIN has the property Reference voltage set to use VREF-A. This does not give information on what sensor it is that is causing the VREF error, but it lets the application know which VIN:s that are affected by a VREF fault.

You are correct about the supply voltage, the XA2 will shut down (supply <6V) before the voltage is insufficient to drive the 5 V VREF.

The most probable explanation to why a VREF drops is if it is overloaded. The XA2 VREF can supply up to 150 mA.
My recommendation is to check what sensors it is that are supplied by this VREF, and see if any of these are overloading the VREF
Hi Gustav, thanks for the reply. That's good to know about the VREF only being able to supply 150mA. That might be my issue...