MGE UPS SYSTEMS

Technical Note 18

The MGE MIB 
(Management Information Base

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Benefits of standardization

After a number of different purchases, a company may well find itself with a group of UPS's of different makes. To administrate all these devices using SNMP, each UPS must use the same variable management system, in other words the MIB (Management Information Base). One of the roles of the IETF is to define a common MIB, for each family of products (routers, servers, network printers, UPS's, etc.). For UPS's, the relevant MIB has been given the reference RFC 1628. The interoperability of UPS's of different makes is guaranteed if they all implement the standard MIB.

Benefits of the MGE MIB

As the IETF UPS MIB is common to several suppliers, it seemed appropriate that MGE offer extensions permitting the full use of functions specific to its products. The RFC 1628 defines 3 levels of compliance: Subset, Basic and Advanced. The level depends on the number of available variables. The MGE MIB complies with the Advanced level of RFC 1628, making it one of the most fully-featured MIB's on the market, with over 160 accessible variables. This high number is due to the fact that a distributed UPS, for a PC, and a redundant 3,600 kVA UPS system protecting a computer center cannot be managed in the same way.
The MGE MIB is currently the only one to have been tested by the IETF and recognized as being RFC 1628 compliant.
The MGE MIB integrates extensions for individual control of electrical power points using the integrated PowerShare function available on Pulsar ESV+ models or on the UM Switch external unit.

The risks involved with proprietary MIB's

Some UPS manufacturers offer non-standard, proprietary MIB's. This represents a two-fold risk for the user:
There is no guarantee that the MIB can be compiled on a given network manager;
Interoperability is impossible with UPS's using the UPS MIB or an RFC 1628-compliant MIB.

In order to avoid these problems, MGE proposes a protocol interface, with a MIB that is RFC 1628-compliant, for connection of any UPS to a UM Link adapter.

Object groups defined by RFC 1628

Group Function
1 Identification Definitions supplied by the user or the UPS regarding hardware and software serial numbers, version numbers, product names, etc.
2 Battery State of UPS, remaining backup time, voltage, current, etc.
3 Input Electrical parameters of the installation, for each phase, including mains voltage, frequency, current , wattage, etc.
4 Output Electrical parameters on the UPS output, for each phase, including voltage, frequency, current, percent load, etc.
5 By Pass Same data variables as for the Input group above.
6 Alarm 24 standard UPS alarms, such as operation on battery power, low battery, battery replacement, overload, overheating, etc.
7 Test Initiates UPS system and battery tests.
8 Control UPS start-up and shutdown, activation of automatic restart, schedule programming, etc.
9 Configuration Setting of rated electrical values, transfer thresholds, activation of audible alarms, etc.
10 Compliance Defines the level of compliance with RFC 1628 (Subset, Basic, Advanced).