Link Bus Scan Period - Nuvation Energy NUV300-BC-12 Product Manual

sc_linkbus.softwareid
▪
Selection of Low-Voltage BMS variant
▪
Set to 0 for NUV300-BC-12
▪
Set to 1 for NUV300-BC-16
sc_linkbus.cicount
▪
Set to 1 for a stand-alone NUV300-BC-12 and NUV300-BC-16
▪
Set to 2 when using a Cell Interface expansion module
sc_linkbus.power_mode
▪
Set to 2 for NUV300-BC-12 and NUV300-BC-16

The Low-Voltage BMS cannot power the Cell Interface module through the Link Bus.
Refer to Section 7.10.5
BMS.

7.10.1. Link Bus Scan Period

The rate at which cell voltage and temperature measurements are updated is determined by a
configurable Link Bus scan period. All cell voltages are measured every scan cycle. Thermistor
temperature measurement is multiplexed across eight consecutive scan cycles. One thermistor in
each group of cells (monitored by a single BMS module) is measured during each cycle, so the
effective scan period of any given thermistor in the system is 8 times the Link Bus scan period.
sc_linkbus.scan_period
▪
Measurement period for cell voltages
▪
This is typically set to 1 second
Performance of passive balancing is also closely related to the scan period. In Nuvation Energy BMS,
a single wiring harness is used to measure cell voltage as well as bleed off passive cell balancing
current. It is not possible to make accurate voltage measurements while simultaneously balancing
cells. To ensure accurate measurement, balancing current flow must stop before measurement can
start (and any transient effects associated with that current flow must be allowed to settle). This is
handled automatically by Nuvation Energy BMS. This means that passive balancing has some duty
cycle that is less than 100% in practical systems.
The Link Bus has a configurable settling period for balancing that corresponds to the amount of time
balancing is left off before voltage measurements are taken.
sc_linkbus.balance_settle_period
▪
Settling period during which balancing is disabled before cell voltage measurement.
▪
Typically set between 50 and 100 ms
For most systems, values between 50 and 100 ms yield accurate, stable measurements. When
coupled with a scan period of 1000 ms, balancing duty cycles above 90% are achievable.
Document ID: NE-PM-002
for details on how to configure the under-voltage feature for the Low-Voltage
Nuvation Energy Low-Voltage BMS - Product Manual
128 Rev 1.2, 2021-03-03
Curie Update 1