Operational Cases For Mesa - Nuvation Energy NUVSSG-1250-100 Product Manual

A write to a writeable MESA point that is unimplemented will generate a Modbus write error.
The MESA implementation on Nuvation Energy BMS has unimplemented points as follows:
Model
801
801
801
801
801
801
802
802
802
802
802
802
802
803
803
7.1.3.4. Scale Factors
All MESA points are integer values (signed or unsigned). To account for different range values beyond
the data size (i.e. greater than 65535 for an unsigned 16 bit value) or some fractional value (i.e.
1.1), some MESA points have scale factors associated with them. The scale factor is another point
within the model which contains a signed integer exponent of base 10 that scales a corresponding
point value. For example, a scale factor of 2 would result in multiplying the corresponding point by
100. Likewise a scale factor of -3 would result in a scale factor of 0.001. Refer to the prior MESA Draft
3 spreadsheet for the relationship between MESA points and their scale factors. All scale factors are
fixed for a model and do not change in value.

7.1.4. Operational Cases for MESA

There are two main operational cases for the control of Nuvation Energy BMS over its MESA interface:
1. An external controller (sometimes called "Energy Storage Controller") is used to coordinate power
Document ID: NE-PM-003
Type Width
(bits)
signed int 16
unsigned int 16
signed int 32
unsigned int 32
enumeration 16
enumeration 32
Table 9. Unimplemented MESA Points
Point Name
Evt
DisChaRate
MaxRsvPct
MinRsvPct
ChaSt
DerAlarmReset
CycleCt
WMaxDisChaRte
SoH
BatReqPCSSt
BatReqW
SoH_SF
BatReqW_SF
StrEvt2
StrConFail
Nuvation Energy High-Voltage BMS - Product Manual
Unimplemented Value
(hexadecimal)
0x8000
0xFFFF
0x80000000
0xFFFFFFFF
0xFFFF
0xFFFFFFFF
Description
Event status bit field
Self Discharge Rate
Maximum Reserve Percent
Minimum Reserve Percent
Charge Status
Alarm Reset (read is unimplemented)
Cycle Count
NamePlate Max Discharge Rate
State of Health (reported in 803 model per string)
PCS State Request
Battery Power Request
State of Health Scale Factor
Battery Power Request Scale Factor
String Event 2
String Connection Fail
65 Rev 1.2, 2021-03-03
Curie Update 1