Technical Tip: PSU sensing does not work for FortiGateRugged-60F/70F in non-isolated positive earth environments
Description
This article describes that the FortiGateRugged-60F/70F DC presence LED may not correctly reflect/detect that one of the DC feeds is down in certain -48VDC environments where users have 2x -48VDC feeds and both feeds are non-isolated positive ground power source.
Scope
FortiGateRugged-60F/70F (Gen 3): P25210-31 and after, FortiGateRugged-60F/70F (Gen 5): P25210-50 and after.
If the user uses a positive ground source (-48V) and the redundant power sources are not isolated. This would result in an issue that would affect the DC presence detection LED behavior.
Solution
The drawings below illustrate the DC LED issue:
- The below illustrates the correct behavior where the positive ground sources are isolated:
- The below illustrates the incorrect behavior where the positive ground sources are not isolated.
This issue only occurs in the case of positive ground sources that are not isolated.
It is recommended to use isolated power sources for power redundancy systems. The issue does NOT affect customers using negative ground power sources and also does not have any impact on other areas of hardware functionality and no impact on safety and regulatory standards for the FortiGateRugged-60F/70F Gen3/Gen5.
