RB850Gx2 Voltage Monitor wrong measurements

Hardware MikroTik hardware general
1

Has anyone noticed an issue with the Voltage monitor on RB850Gx2?

I use a central UPS for all my RBs providing ~27 Volts to all devices.

But RB850Gx2 measures 28V instead of 27V.
I double checked with my multimeter that indeed 27V reach the RB850Gx2 and not more.
Also if it goes over 28V (as in 100mV more) the Voltage Monitor field in System>Health completely disappears. If it goes back down to lower or equal to 28V it reappears.

I turned down the voltage by about 500mV and it now shows 27.6Volts steadily while the rest of the devices show the proper 26.5V.

So it appears there are two problems with Voltage Monitor on RB850Gx2.

  1. The voltage monitor is showing more than it actually gets.
  2. The voltage monitor stops working if it (thinks) it has more than 28Volts.

These results are on v6.39.2. I don’t see anything related to the changelogs of newer versions and at the moment I cannot upgrade this unit to the latest version.

2

Double check Fimrware is up to date. If it is, generate a supout and email support linking to this post.

3

I was asking the community if anyone else has noticed this discrepancy with the voltage monitor.

There hasn’t been any firmware update for my RB850Gx2 since I bought it (it’s the second revision with hw acceleration for IPsec).

> /system routerboard print 
       routerboard: yes
             model: 850Gx2
     serial-number: XXXXXXXX
     firmware-type: p1023
  factory-firmware: 3.24
  current-firmware: 3.24
  upgrade-firmware: 3.24
4

I suggested supout/support route because looks like a bug and Mikrotik would better know…

5

I understand what you mean but again, I am asking the community (not Mikrotik support) if they have observed the same issue on this RB model.
I am not asking for a solution, just confirmation by other users. If I had a second RB805Gx2 I would confirm it myself.

This is an insignificant bug for me to have to send a supout (ie: disclose sensitive information and configuration to Mikrotik) or upgrade to the latest version and retry (since this is the standard Mikrotik policy/reply when sending a bug report).