With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cefcPSOutputModeIndex
Cisco Entity Field Replaceable Unit Control PS Output Mode Index
1.3.6.1.4.1.9.9.117.1.6.2.1.1
A unique value, greater than zero, for each possible output mode on a power supply.
Back to CISCO-ENTITY-FRU-CONTROL-MIB MIB page.
IPHost Network monitor allows you to monitor cefcPSOutputModeIndex on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco firewalls right now.