Modbus Registers (Elms To Sicharge) - Siemens SICHARGE D Operating Instructions Manual

2.5

Modbus registers (ELMS to SICHARGE)

All Modbus registers in SICHARGE are holding registers. Floating point values are transmitted as
integers after a scaling factor is applied to shift the decimal places. These registers can be written
by the ELMS via the Modbus TCP communication protocol. Mappings are shown in the table
below.
Table 2-3
Name
Control word 1
EVSE active power limit setpoint (G_PowerLimit)
Measured average EVSE active power (EMA_Power)
Fallback power limit setpoint (G_FallbackPLim)
Control word 1
The bit-wise split of the control word from the ELMS to SICHARGE and its description are
discussed below. Note that in this case LSB is bit 0 and MSB is bit 15.
• Bit 00 – Load Limitation Active (ELMS_LLA)
Key software control flag for ELMS. The power limit setpoints sent via the ELMS are only taken
into account if this flag is set. It is essential to keep this flag set to "true" to ensure correct
working of the feature. If this flag is set to "false", the ELMS feature remains deactivated, even
though the Modbus communication error is absent.
• Bit 01 – TRIP Line Activated (ELMS_NoTRP_A)
Provides information to SICHARGE when the safety loop has been activated and the entire
charger has been put into the emergency shutdown state. Set this flag to "false" when the trip
line is activated via the hardwired signal (normally closed -> open); otherwise ensure this
flag is set to "true".
• Bit 02 – External Measurement Available (EMA)
Informs SICHARGE that the power consumption of the charger is being measured by an
external energy meter at the ELMS end and that the readings are available on the Measured
EVSE Active Power (EMA_Power) Modbus register. Set this flag to "true" if an external energy
meter is available, communication with it is healthy, and power readings from it are in the
plausible range. If any of these conditions are not satisfied, then ensure this flag is set to
"false".
• Bit 14 – Heartbeat ELMS Active (HB_ELMS_A)
Informs SICHARGE that the optional sub-feature "Heartbeat Monitoring" can be
made available to detect a communication loss scenario faster and react to it quickly with the
Fallback Power Limit Setpoint. Set this flag to "true" if this feature is supported by the
controller at the ELMS end; otherwise ensure this flag is set to "false".
• Bit 15 – Heartbeat ELMS (HB_ELMS)
Returns heartbeat pulses from the ELMS to SICHARGE. This flag is only taken into account if
HB_ELMS_A = true. Please note that for this heartbeat monitoring sub-feature, the ELMS
does not need to generate any pulses and is only required to return the pulses issued by the
SICHARGE on status word bit 15 - Heartbeat SICHARGE D (HB_S) on this flag.
External Load Management System
Operating Manual, 07/2022, A5E52045935-AA
Modbus registers (write to SICHARGE)
2.5 Modbus registers (ELMS to SICHARGE)
Addr Type
0 word
1 uint
2 uint
3 uint
Description
Factor Units
- -
100 kW
100 kW
100 kW
15