SNMP MIB User Guide
Raritan Inc.
August 21, 2020

SNMP MIB User Guide

CONTENTS

Contents
Contentsii

1 Quick Start
1.1 Determine the status of an outlet . . . . . . . . . . . . . . . . . . . . . .
1.2 Power cycle an outlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 Get the voltage reading of an inlet . . . . . . . . . . . . . . . . . . . . .
1.4 Get the number of decimal digits of an inlet voltage reading . . . . . . .
1.5 Receive a trap message on an external sensor alarm assertion . . . . . . .
1.6 Get an asset management tag ID . . . . . . . . . . . . . . . . . . . . . .
1.7 Set the name of a rack unit in asset management . . . . . . . . . . . . .

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1
2
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3
4
5
5

2 About this document
2.1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6
6
6
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3 Capabilities

7

4 Access
4.1 SNMP Interface Configuration . . . . . . . . . . . . . . . . . . . . . . . .
4.2 Protocol Versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3 MIB Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4 Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8
8
8
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5 Object Indexing
5.1 Scalar Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2 Columnar Objects – Single Index . . . . . . . . . . . . . . . . . . . . . .
5.3 Columnar Objects – Multiple Indexes . . . . . . . . . . . . . . . . . . . .

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11
11
13

6 MIB tree

16

7 Interpreting Sensor Values
7.1 Decimal Digits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2 Signed vs. Unsigned . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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QUICK START

Quick Start

This section contains some brief examples of tasks that can be performed on a PDU’s
SNMP interface. All of them assume the following preconditions:• SNMP was set up as shown in figure 1 and 2 in section 4.1• the Net-SNMP tools are installed (see www.net-snmp.org)• the MIB files (see section 4.3 how to get them) are located in the MIB search path,
which can be adjusted by adding -M+<path> to the snmp command arguments
Each example will present the MIB object identifier to deal with and an SNMP commandline with related execution output. The object identifier includes the applicable variables,e. g. “<outlet number>” which are replaced with actual values in the command andoutput example.

1.1

Determine the status of an outlet

Complete Object Identifier:
PDU2-MIB::pdu2.control.outletControl.outletSwitchControlTable.outletSwitchControlEntry.outletSwitchingState.<pdu id>.<outlet number>Command:snmpget -v2c -c public -m+PDU2-MIB <pdu IP address> \PDU2-MIB::outletSwitchingState.1.4
snmpget -v2c -c public <pdu IP address> \.1.3.6.1.4.1.13742.6.4.1.2.1.3.1.4
Output:PDU2-MIB::outletSwitchingState.1.4 = INTEGER: off(8)Page 1

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1.2

1

QUICK START

Power cycle an outlet

Complete Object Identifier:
PDU2-MIB::pdu2.control.outletControl.outletSwitchControlTable.outletSwitchControlEntry.switchingOperation.<pdu id>.<outlet number>Command:snmpset -v2c -c private -m+PDU2-MIB <pdu IP address> \PDU2-MIB::switchingOperation.1.4 = cycle
snmpset -v2c -c private <pdu IP address> \.1.3.6.1.4.1.13742.6.4.1.2.1.2.1.4 i 2
Output:PDU2-MIB::switchingOperation.1.4 = INTEGER: cycle(2)1.3

Get the voltage reading of an inlet

Complete Object Identifiers:
PDU2-MIB::pdu2.measurements.measurementsInlet.inletSensorMeasurementsTable.inletSensorMeasurementsEntry.measurementsInletSensorValue.<pdu id>.<inlet number>.<sensor type>Command:snmpget -v2c -c public -m+PDU2-MIB <pdu IP address> \PDU2-MIB::measurementsInletSensorValue.1.1.rmsVoltage
snmpget -v2c -c public <pdu IP address> \.1.3.6.1.4.1.13742.6.5.2.3.1.4.1.1.4
Output:PDU2-MIB::measurementsInletSensorValue.1.1.rmsVoltage = Gauge32: 397

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1.4

1

QUICK START

Get the number of decimal digits of an inlet voltage reading

Complete Object Identifier:
PDU2-MIB::pdu2.configuration.inlets.inletSensorConfigurationTable.inletSensorConfigurationEntry.inletSensorDecimalDigits.<pdu id>.<inlet number>.<sensor type>Command:snmpget -v2c -c public -m+PDU2-MIB <pdu IP address> \PDU2-MIB::inletSensorDecimalDigits.1.1.rmsVoltage
snmpget -v2c -c public <pdu IP address> \.1.3.6.1.4.1.13742.6.3.3.4.1.7.1.1.4
Output:PDU2-MIB::inletSensorDecimalDigits.1.1.rmsVoltage = Gauge32: 0

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1.5

1

QUICK START

Receive a trap message on an external sensor alarm assertion

Complete Object Identifier:
PDU2-MIB::pdu2.traps.externalSensorStateChange
snmptrapd Configuration File:
The host that should receive the SNMP notification messages needs to run snmptrapd. Its configuration file is usually located at /etc/snmp/snmptrapd.confand specifies at least the community string and the object identifiers that should
be handled. A minimalistic configuration for logging external sensor state changes
will just contain two lines:
authCommunity log publictraphandle PDU2-MIB::externalSensorStateChange
Note that the string “public” must be specified in the SNMP notification settingsof the PDU, see section 4.1.
Command:snmptrapd -m+PDU2-MIB
Output:On reception of an SNMP trap the daemon will print the trap contents to its console.
The output will be printed without line breaks, the example has them to increase
readability.
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (36334) 0:06:03.34
SNMPv2-MIB::snmpTrapOID.0 = OID: PDU2-MIB::externalSensorStateChange
PDU2-MIB::pduName = STRING: My PX
PDU2-MIB::pduNumber = INTEGER: 0
PDU2-MIB::pxInetAddressType = INTEGER: ipv4(1)PDU2-MIB::pxInetIPAddress = Hex-STRING: C0 A8 02 93
PDU2-MIB::agentInetPortNumber = Gauge32: 161
PDU2-MIB::externalSensorNumber = INTEGER: 25
PDU2-MIB::typeOfSensor = INTEGER: humidity(11)PDU2-MIB::measurementsExternalSensorTimeStamp = Gauge32: 1456130186
PDU2-MIB::measurementsExternalSensorValue = INTEGER: 42
PDU2-MIB::measurementsExternalSensorState = INTEGER: belowLowerWarning(3)PDU2-MIB::oldSensorState = INTEGER: normal(4)PDU2-MIB::externalSensorSerialNumber = STRING: AAR3Sh0005
PDU2-MIB::externalOnOffSensorSubtype = INTEGER: none(31)PDU2-MIB::externalSensorChannelNumber = INTEGER: -1
SNMPv2-MIB::sysContact = STRING: n/a
SNMPv2-MIB::sysName = STRING: n/a
SNMPv2-MIB::sysLocation = STRING: n/aPage 4

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1.6

1

QUICK START

Get an asset management tag ID

Complete Object Identifier:
ASSETMANAGEMENT-MIB::assetManager.configuration.assetManagement.assetManagementTable.assetManagementEntry.tagID.<asset strip number>.<rack unit index>
Command:snmpget -v2c -c public -m+ASSETMANAGEMENT-MIB <pdu IP address> \ASSETMANAGEMENT-MIB::tagID.1.5
snmpget -v2c -c public <pdu IP address> \.1.3.6.1.4.1.13742.7.1.7.1.1.6.1.5
Output:ASSETMANAGEMENT-MIB::tagID.1.5 = STRING: B1A0C499D35F

1.7

Set the name of a rack unit in asset management

Complete Object Identifier:
ASSETMANAGEMENT-MIB::assetManager.configuration.assetManagement.assetManagementTable.assetManagementEntry.rackUnitName.<asset strip number>.<rack unit index>
Command:snmpset -v2c -c private -m+ASSETMANAGEMENT-MIB <pdu IP address> \ASSETMANAGEMENT-MIB::rackUnitName.1.5 = MyName
snmpset -v2c -c private <pdu IP address> \.1.3.6.1.4.1.13742.7.1.7.1.1.12.1.5 s MyName
Output:ASSETMANAGEMENT-MIB::rackUnitName.1.5 = STRING: MyName

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About this document

2.1

Scope

2

ABOUT THIS DOCUMENTThe Raritan PDU SNMP MIB User Guide provides information about the following:• configuration, access and capabilities of the SNMP interface• usage of tables• structure of the PDU’s Management Information BaseThis document applies to the following Raritan PDU devices:• PX2 / PX3 / PX3TS• EMX• BCM2 / PMC
• BCM
• PXE
The very basics of the SNMP protocol and the SMI concepts are not covered. Tools
like MIB browsers or snmp utilities are not explained as well. This documents describes
how the SNMP interface of a Raritan PDU can be utilized by the SNMP protocol by forexample using such tools.

2.2

Audience

This document should primarily guide
Data Center Operators who want to configure PDUs, request values or control states
sporadically,
DCIM software developers who want to integrate PDUs into higher level management frameworks andScript Developers who want to write code that uses the PDU’s SNMP interface.

2.3

Prerequisites

This document presumes understanding of• Structured Management Information (SMI),• the Simple Network Management Protocol (SNMP) and• Management Information Base (MIB) documents.

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CAPABILITIESCapabilities

The SNMP interface has almost the same capabilities as the web interface and the serialcommand line interface. It can be used to:• retrieve logged and current sensor measurements• get notifications on events• control actuators• configure names, thresholds etc.
The following features are not accessable via SNMP:• User Management• Network Configuration• Services Configuration• Event Rule Configuration

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4

Access

4.1

SNMP Interface Configuration

ACCESSThe unit’s SNMP interface can be enabled and set up in the web frontend or commandline interface. The settings dialog can be found in the menu under Device Settings /Network Services / SNMP.

Figure 1: SNMP settings dialog of web user interface

4.2

Protocol Versions

Both SNMP v1/v2c and v3 versions are supported. They can be enabled or disabledindependently.

4.3

MIB Version

While changes of the MIB may happen between different PDU firmware versions, allchanges are done in a downward compatible way. The used MIB should be newer than
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ACCESS

Figure 2: SNMP notification settings dialog of the web user interface

or as current as the firmware of the PDU. A PDU’s MIB can be downloaded from the
web user interface of the unit – see the “Download” button in the left bottom corner of
the SNMP settings dialog (figure 1). There are three different MIB files:• PDU2-MIB• ASSETMANAGEMENT-MIB• LHX-MIB

4.4

Authentication

In SNMP v1/v2c authentication is accomplished with community strings. The read aswell as the write community string can be configured in the SNMP settings (see figure 1).
SNMP v3 authentication is set up on a per user basis. The settings are accessible
in user settings (see figure 3).
An example command that uses SNMP v3 access to display the whole object tree
below the PDU2-MIB::pdu2 object is:Page 9

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ACCESS

Figure 3: SNMP v3 user setup dialog of web user interface

snmpwalk -v3 -l authPriv -u <username> \-a SHA -A <authentication passphrase> \-x DES -X <privacy passphrase> \<pdu IP address> PDU2-MIB::pdu2
Arguments:-l security level – “noAuthNoPriv”, “authNoPriv”, “authPriv”-a authentication protocol – “MD5”, “SHA”-x privacy protocol – “DES”, “AES”

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5

Object Indexing

5.1

Scalar Objects

OBJECT INDEXING

Information unique to an SNMP agent is represented by “scalar” objects. An example is
pduCount which is located at
PDU2-MIB::pdu2.configuration.pduCount
Scalar objects are marked out as such by appending a zero to their object identifier.
PDU2-MIB::pdu2.configuration.pduCount.0 = INTEGER: 1
In numerical representation:.1.3.6.1.4.1.13742.6.3.1.0 = INTEGER: 1
Since one SNMP agent running on a PDU is not limited to represent only a single PDU
instance, most information entities are indexed by the PDU identifier – pduId – which
is fixed to 1 for PX products but may vary on BCM2 products.
pduId OBJECT-TYPE
SYNTAX Integer32(0..256)
DESCRIPTION"A unique value for each PDU/Power meter.
PX2/3 and transfer switch: pduId = 1
BCM2:
main controller: pduId = 0
power meter: pduId = rotary switch setting
for the power meter
It is the same as the MeterID in the GUI
Example:a power meter, rotary switch setting = 5,
pduId = 5
a panel (power meter + branch metering),
rotary switch setting = 23, pduId = 23"

This “indexed” information is structured in tables as described in the next section.

5.2

Columnar Objects – Single Index

This section explains the use of SNMP tables in the PDU2-MIB that are indexed by asingle value. Consider the following example:

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OBJECT INDEXING

nameplateTable OBJECT-TYPE
SYNTAXSEQUENCE OF NameplateEntryStruct...
DESCRIPTION"A list of PDU nameplate entries. The number of
entries is given by the value of pduCount."::= { unit 1 }nameplateEntry OBJECT-TYPE
SYNTAX
NameplateEntryStruct...
DESCRIPTION"An entry providing PDU nameplate information."
INDEX{ pduId }::= { nameplateTable 1 }NameplateEntryStruct ::= SEQUENCE {pduId
Integer32,
pduManufacturer
DisplayString,
pduModelDisplayString,
pduSerialNumber
DisplayString,
pduRatedVoltage
DisplayString,
pduRatedCurrent
DisplayString,
pduRatedFrequency DisplayString,
pduRatedVA
DisplayString,
pduImage
DisplayString}

This part of the MIB defines a one-dimensional table of entries that hold nameplateinformation. It is one-dimensional because the INDEX clause contains a single identifier.
nameplateEntry OBJECT-TYPE...
INDEX { pduId }...

One entry in the table corresponds to one PDU and a pduId value is sufficient tospecify an entry in the table. See table 1 and 2 as examples. An SNMP agent runningon a PX has a single PDU identifier with the value 1 for that PX per definition, as in thefirst example. The second example shows the nameplate table of a BCM2 device that
may have multiple PDU identifiers.
pduId1

pduManufacturer“Raritan”

pduModel“PX3-5526X2-M5”

pduSerialNumber“da119317649bb578”

pduId.1

pduManufacturer.1

pduModel.1

pduSerialNumber.1...

Table 1: Nameplate table of a PDU
The table structure is built as follows. Each cell of the table header corresponds toone member of the NameplateEntryStruct sequence. The cells of the tables body are
the objects. Their object identifiers are noted below.
As a detailed example, the full SNMP object identifier of the PDU model string intable 1 “PX3-5526X2-M5” is broken down in table 3.
To address objects in the table, the shortened symbolic object identifier consists ofthe column name and the index. For example the pduModel string (from NameplateEntryStruct) of PDU 1 is:Page 12

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OBJECT INDEXING

pduId
0

pduManufacturer“Raritan”

pduModel“PMC-1001”

pduSerialNumber“da119317649bb579”

pduId.0

pduManufacturer.0

pduModel.0

pduSerialNumber.0

4“Raritan”“PMM”“00000000”

pduId.4

pduManufacturer.4

pduModel.4

pduSerialNumber.4

5“Raritan”“PMM”“00000000”

pduId.5

pduManufacturer.5

pduModel.5

pduSerialNumber.5

11“Raritan”“PMM”“00000000”

pduId.11

pduManufacturer.11

pduModel.11

pduSerialNumber.11...

Table 2: Nameplate table of a PMC with three PMMs
Numerical.1.3.6.1.4.1.13742
.6
.3
.2
.1
.1
.3
.1

Symbolic.iso.org.dod.internet.private.enterprises.raritan.pdu2.configuration.unit.nameplateTable.nameplateEntry.pduModel.<pdu id>Notetable object
defines columns and index
selected column
index / selected row

Table 3: Object identifier of PDU model string in the unit’s nameplate table

PDU2-MIB::pduModel.1

Note: Most object identifiers that are used as indexes or parts of indexes like “outletId”,“inletPoleIndex” or “circuitId” are 1-based integer values.

5.3

Columnar Objects – Multiple Indexes

In cases where a single value is not sufficient as an index to a table of objects, the index
may consist of multiple instances of identifiers. Consider the table that holds outlet sensor
measurement variables outletSensorMeasurementsTable.

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OBJECT INDEXING

outletSensorMeasurementsTable OBJECT-TYPE
SYNTAXSEQUENCE OF OutletSensorMeasurementsEntryStruct...
DESCRIPTION"A list of outlet sensor entries. The number of
entries is given by the value of outletCount for the PDU."::= { measurementsOutlet 3 }outletSensorMeasurementsEntry OBJECT-TYPE
SYNTAX
OutletSensorMeasurementsEntryStruct...
DESCRIPTION"An entry containing measurement objects for an outlet sensor."
INDEX{ pduId, outletId, sensorType }::= { outletSensorMeasurementsTable 1 }OutletSensorMeasurementsEntryStruct ::= SEQUENCE {measurementsOutletSensorIsAvailable TruthValue,measurementsOutletSensorState
SensorStateEnumeration,measurementsOutletSensorValue
Unsigned32,
measurementsOutletSensorTimeStamp
Unsigned32,
measurementsOutletSensorSignedValue Integer32}

The structure is the same as in section 5.2 – table object, entry object and the table
columns. The difference here is the INDEX clause.
outletSensorMeasurementsEntry OBJECT-TYPE
...
INDEX
{ pduId, outletId, sensorType }...

The definition states that the index consists of three parts. Each outlet sensor within
one SNMP agent is identified by its PDU’s identifier, its outlet number and the type ofthe sensor. The index that is appended to the object identifier of outletSensorMeasurementsEntry is formed by these three parts. For example, an object identifier tothe measurementsOutletSensorValue of the active power of the fifth outlet is formed
as shown in table 4.
Numerical.1.3.6.1.4.1.13742
.6
.5
.4
.3
.1
.4
.1
.5
.5

Symbolic.iso.org.dod.internet.private.enterprises.raritan.pdu2.measurements.measurementsOutlet.outletSensorMeasurementsTable.outletSensorMeasurementsEntry.measurementsOutletSensorValue.<pdu id>.<outlet number>.<sensor type>

Note

table object
defines columns and index
selected column)

indexes / selected row

Table 4: Object identifier of active power sensor value of the fifth outlet

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OBJECT INDEXINGThe symbolic object identifier can be shortened to:
PDU2-MIB::measurementsOutletSensorValue.1.5.activePowerAs another example, table 5 shows a part of the whole outlet sensor measurements
table. The first column contains the index of the entries starting with the rmsCurrent
sensor of the fourth outlet.
Index
1.4.rmsCurrent
1.4.rmsVoltage
1.4.onOff
1.4.frequency
1.5.rmsCurrent
1.5.rmsVoltage
1.5.onOff

measurementsOutletSensorIsAvailable SensorState SensorValue...
true
normal151
true
normal
229
...
true
on
0
true
normal500
truenormal0
true
normal
0
...
true
off
0
...

...

Table 5: Parts of the outlet sensor measurements table that show sensors of outlets
number 4 and 5

To inspect SNMP tables the snmptable command might be useful, for example
snmptable -m+PDU2-MIB -v2c -cpublic -Cilb <pdu IP address> \PDU2-MIB::inletSensorConfigurationTable | cut -c1-57

prints a nicely readable left hand part of the inlet sensor configuration table:
index
LogAvailable Units
DecimalDigits
1.1.rmsCurrent
false
amp
3
1.1.unbalancedCurrent false
percent 0
1.1.rmsVoltage
false
volt
0
1.1.activePower
false
watt
0
1.1.apparentPower
false
voltamp 0
1.1.powerFactor
false
none
2
1.1.activeEnergy
false
wattHour 0
1.1.frequency
false
hertz
1
1.1.residualCurrent
false
amp
3
1.1.rcmState
false
none
0
1.2.rmsCurrent
false
amp
3
1.2.unbalancedCurrent false
percent 0
1.2.rmsVoltage
false
volt
0
1.2.activePower
false
watt
0
1.2.apparentPower
false
voltamp 0
1.2.powerFactor
false
none
2
1.2.activeEnergy
false
wattHour 0
1.2.frequency
false
hertz
1
1.2.residualCurrent
false
amp
3
1.2.rcmState
false
none
0

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6

MIB TREE

MIB treeThis section describes the basic structure of the PDU2-MIB tree. The following clip of
the PDU2-MIB file shows the various subtrees that reside below the PDU2-MIB::pdu2
object:raritan MODULE-IDENTITY...
::= { enterprises 13742 }
pdu2 OBJECT IDENTIFIER ::= { raritan 6 }traps
OBJECT IDENTIFIER ::= { pdu2 0 }board
OBJECT IDENTIFIER ::= { pdu2 1 }environmental OBJECT IDENTIFIER ::= { pdu2 2 }configuration OBJECT IDENTIFIER ::= { pdu2 3 }control
OBJECT IDENTIFIER ::= { pdu2 4 }measurements OBJECT IDENTIFIER ::= { pdu2 5 }log
OBJECT IDENTIFIER ::= { pdu2 6 }conformance
OBJECT IDENTIFIER ::= { pdu2 9 }reliability
OBJECT IDENTIFIER ::= { pdu2 10 }The subtree configuration contains most of the information that is writable / configurable. The measurements and log subtrees contain sensor values and state information. The control subtree allows manipulation of the PDU such as switching outlets
or resetting energy counters.
Table 6 shows the most commonly used tables of the PDU2-MIB. Each cell represents a name that is built by its column name and its row name appended. An “x”
mark states that a table with this name can actually be found in the MIB. For example:
unitConfigurationTable does exist while unitPoleConfigurationTable does not.
Prefixes
overCurrent- powertransferTables unit inlet outlet Protector Meter circuit Switch
ConfigurationTable
x
x
x
x
x
x
x
PoleConfigurationTable
x
x
x
x
x
SensorConfigurationTable
x
x
x
x
x
x
PoleSensorConfigurationTablexxx
SwitchControlTablexx1
SensorControlTablexxxx
SensorMeasurementsTable
x
x
x
x
x
x
PoleSensorMeasurementsTablexxx
SensorLogTable
x
x
x
x
x
x
PoleSensorLogTablexxx

Table 6: Table names present in the MIB
The particular contents of these tables are quite common:-ConfigurationTable
Contains metadata, capabilities, configuration and state information of the PDU’s
parts; for example the current rating of an outlet or the unit’s IP address.
1

The actual name is “transferSwitchControlTable” rather than transferSwitchSwitchControlTable.
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MIB TREE-SensorConfigurationTable
Contains sensor metadata such as accuracy or tolerance and the sensors’ thresholds.
-SwitchControlTable
Contains objects that allow switching of outlets or between inlets of a transfer
switch.
-SensorControlTable
Contains objects that allow resetting of cumulating sensor values such as energy
counters.
-SensorMeasurementsTable
Contains sensor readings and state information.
-SensorLogTable
Contains objects to access logged measurements data such as minimum, maximum
and average values.
To inspect parts of the tree, the tool snmptranslate can be used. Using the commandline option -Tp the whole subtree below the object identifier submitted to the command
will be displayed in human readable format. For example:
snmptranslate -m+PDU2-MIB -Tp PDU2-MIB::pdu2
...
|
|
|
|
|
|
|
|
|
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| |
| +--transferSwitchPoleConfigurationTable(5)|||+--transferSwitchPoleConfigurationEntry(1)|| Index: pduId, transferSwitchId, transferSwitchPoleIndex|||+-- ---- Integer32 transferSwitchPoleIndex(1)||Range: 1..256|+-- -R-- EnumValtransferSwitchPoleLine(2)||Textual Convention: LineEnumeration||
Values: lineL1(1), lineL2(2), lineL3(3), lineNeutral(4)|+-- -R-- Integer32 transferSwitchPoleIn1Node(3)|+-- -R-- Integer32 transferSwitchPoleIn2Node(4)|+-- -R-- Integer32 transferSwitchPoleOutNode(5)|+--powerMeter(10)| || +--powerMeterConfigurationTable(2)|||+--powerMeterConfigurationEntry(1)|| Index: pduId|||+-- -RW- Unsigned powerMeterPhaseCTRating(2)...

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7

Interpreting Sensor Values

7.1

Decimal Digits

7

INTERPRETING SENSOR VALUES

All sensor readings are reported as integer values. Since the actual values may havefractional parts, it could be necessary to adjust to the number of decimal digits. Therefore
each SensorConfigurationTable has a column called DecimalDigits. See section 1.4
for an example. To calculate the actual value the integer reading value must be divided
by ten to the power of the decimal digits. Additionally, the column SensorUnits of theSensorConfigurationTable can be read to determine the unit of the reading.
For example:
PDU2-MIB::inletSensorDecimalDigits.1.1.rmsCurrent = Gauge32: 3
PDU2-MIB::measurementsInletSensorValue.1.1.rmsCurrent = Gauge32: 1424
PDU2-MIB::inletSensorUnits.1.1.rmsCurrent = INTEGER: amp(2)= 1.424 A.
These values would mean that the inlet current is 1424
103

7.2

Signed vs. Unsigned

Sensor readings are reported as integer values. Since some types of sensors can have negative values it is important to know if the integer value must be interpreted as a signed
or an unsigned number. To determine the signedness of a reading, the according SensorSignedMinimum in the SensorConfigurationTable must be checked for a negativevalue. If a sensor can have negative values, the SensorSignedValue in the MeasurementsTable must be used to determine the sensor reading and the unsigned SensorValue object will not exist for this sensor. Otherwise the unsigned SensorValue canbe used. If a sensor reading can exceed the value of IN T 32_M AX = 2147483647, thatis if SensorMaximum in the SensorConfigurationTable is above IN T 32_M AX,
the unsigned SensorValue in the MeasurementsTable must be used and the SensorSignedValue object will not exist. See table 7.
Table
ColumnCases

SensorConfigurationTable
SensorSignedMinimum SensorMaximum(INTEGER)(Gauge32)≥0≤ IN T 32_M AX≥0> IN T 32_M AX<0≤ IN T 32_M AX<0> IN T 32_M AX

MeasurementsTable
SensorSignedValue SensorValue(INTEGER)(Gauge32)
yes
yes
no
yes
yes
no
does not apply

Table 7: Determination which sensor reading values to use.

For example:
PDU2-MIB::circuitSensorSignedMinimum.1.1.phaseAngle = INTEGER: -1800
PDU2-MIB::measurementsInletPoleSensorSignedValue.1.1.3.phaseAngle = INTEGER: -1200

The first line states that the phase angle sensor value can have negative values. That
indicates that the signed integer has to be used. In the above example the phase angle
is −120 degrees.
The same procedure applies to determining whether the signed or unsigned values
must be used when reading sensor thresholds or sensor log entries.
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