SC300 Handbook
70
Copyright © 2007-2018 Eaton Corporation. All Rights Reserved.
IPN 997-00012-03 B2 Issue B2 July 2018
Battery Mid-point Monitoring (MPM) and Quarter-point monitoring (QPM)
The SC300 uses the same settings for MPM and QPM.
Where text refers to MPM or Mid-point monitoring below, it includes quarter-point monitoring
unless otherwise stated.
Battery Mid-point monitoring and Quarter-point monitoring provide cost-effective methods for the
early detection of internal battery faults.
The voltages of the two halves or quarters of a battery string are measured and the system
controller generates an alarm signal if a voltage imbalance is detected.
A voltage imbalance is an indication that one or more cells has an internal fault. Further
investigation can then isolate the faulty cell(s) and action can be taken to correct the problem and
prevent a total battery failure.
To connect Battery Mid-point Monitoring see details in the dc power system Installation and
Operation Guide. If a
String Fail
alarm is generated see Troubleshooting on page 122.
To ensure reliable operation MPM / QPM operate only when the battery is in float charge and
after a configurable lockout period since the last battery discharge, Fast Charge, Equalize or Battery
Test.
Quarter-point monitoring requires the one of these IO Boards : IOBGP-10/11/20/21.
The IOBGP-00/01 only supports mid-point monitoring.
► To enable Battery Mid-point Monitoring (MPM) or Quarter-Point Monitoring (QPM)
If any of the mid-point monitoring analog inputs are used for Reverse Battery Detection (see
details on page 77) then they are not available for MPM/QPM.
1
Connect the mid-point monitoring sense wires to the batteries. Refer to the dc power system
Installation and Operation Guide.
There are four mid-point / quarter-point monitoring analog inputs on an IOBGP Input / Output
board. Up to 20 additional battery strings can be monitored if additional IOBGP Input / Output
boards are connected. Refer to the dc power system Installation and Operation Guide for details
on how to connect additional IOBGP Input / Output boards to the SC300.
2
In DCTools/Web go to
Batteries
.
3
Set
Cells Per String
to the number of 2V cells per string (for example: 24 for 48V nominal
system).
4
Expand the
Mid-point Monitoring
table.
5
Set
MPM Enable
to
Enabled
and check the configuration settings (see details on page 72).
6
Go to
Analog Inputs
and
Enable
the mid-point / quarter-point monitoring analog inputs as
required.
For Mid-point monitoring, battery strings 1-4 will be connected to IOB Number 1, IOB AI
Numbers 2-5. Battery strings 5-8 will be connected to IOB Number 2, IOB AI Numbers 2-5. And
so on, as required up to string 24.
For quarter-point monitoring, each string requires a Battery First Quarter Point, a Battery
Midpoint, and a Battery Third Quarter Point input to be connected. Each IO Board can measure
quarter-points for one string, plus one spare input. For instance, four strings requires 12 analog
inputs, which can be achieved with three IO Boards.
7
Go to
Alarms
>
Alarm States
. Enable and configure the
String Fail
alarm. See System Alarm
Configuration on page 57.
► To clear a String Fail alarm
1
On the web, go to
Batteries
>
Mid-point Battery Monitoring
(expand the
table).
