Siemens SICHARGE D User manual
Operating Instructions
8EM5907-0AA00-1AA8.01
External Load Management System
07/2022Edition
SICHARGE
siemens.com/sicharge-d
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A5E52045935-AA
Ⓟ 11/2022 Subject to change
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Table of contents
1 Overview................................................................................................................................................ 5
1.1 About the document............................................................................................................ 5
1.2 About the feature ................................................................................................................ 5
2 Description............................................................................................................................................. 7
2.1 Working Principle................................................................................................................. 7
2.2 Sub-Features........................................................................................................................ 8
2.3 Communications................................................................................................................ 12
2.4 Trip line (Emergency loop) ................................................................................................. 14
2.5 Modbus registers (ELMS to SICHARGE)................................................................................ 15
2.6 Modbus registers (SICHARGE to ELMS)................................................................................ 16
3 Commissioning .................................................................................................................................... 23
3.1 Settings on SICHARGE conguration backend (SCB) ............................................................ 23
3.2 Safety loop testing using TRIP line ...................................................................................... 25
3.3 Power limiting via ELMS..................................................................................................... 26
3.4 Fallback power limit via ELMS............................................................................................. 27
External Load Management System
Operating Manual, 07/2022, A5E52045935-AA 3
Table of contents
External Load Management System
4Operating Manual, 07/2022, A5E52045935-AA
Overview 1
1.1 About the document
This document is an annex to the operating instructions for an optional feature named the
"External Load Management System" developed for SICHARGE D (EV charger). It is always to be
referred to in conjunction with the Operating Instructions (8EM5907-0AA00-1AA7), Repair
Instruction (8EM5907‑0AA00‑4AA1), and Software Handbook (8EM5907‑0AA00‑4AA6) which
form the basic documentation of SICHARGED.
Safekeeping the operating instructions
The operating instructions are an integral part of the product and an indispensable part of the
product safety concept. The following requirements therefore apply for safekeeping of the
operating instructions:
• Keep the operating instructions for the entire service life of the charging station.
• Make the operating instructions easily accessible at all times, for all persons involved.
• If you pass the charging station on to third parties, then also hand over the operating
instructions.
Using the operating instructions
How to use the operating instructions correctly?
• Make the operating instructions available to all persons involved before and during work on
the charging station.
• Read the operating instructions carefully before starting work.
• Follow the safety instructions and instructions.
• Disregarding the information in this operating manual can lead to personal injury, property
damage, dangerous situations, and loss of warranty.
1.2 About the feature
The External Load Management System, hereafter referred to by the acronym 'ELMS', is an
optional feature for SICHARGE D electric vehicles chargers. The main function of this feature is
to enable limiting of the power drawn from the incomer of the SICHARGE charger below a
specied external setpoint over the communication interface.
Preconditions to using ELMS
• Firmware version V2.5.2 or higher
• Chargers need to be equipped and congured for ELMS (available as an option)
External Load Management System
Operating Manual, 07/2022, A5E52045935-AA 5
Note
ELMS feature also works without an AC incomer meter.
Note
The PLC can only control the real power consumption P of the charger. The reactive power due
to installed EMC lters cannot be controlled. In standby mode, real power P is low, and the
reactive power Q constitutes the major part of the apparent power S. As soon as the load
increases, the power factor rapidly increases to > 0.9 and beyond.
Note
If ELMS is congured, Router 1 cannot establish a connection to the internet via the wired WAN
since ELMS uses this interface.
Overview
1.2About the feature
External Load Management System
6Operating Manual, 07/2022, A5E52045935-AA
Description 2
2.1 Working Principle
The ELMS feature needs to be activated to start operation. The activation procedure shall be
explained in further sections. The processing on external specied power limit setpoint is done
by SICHARGED charger and can be described as follows.
Sequence of operation
• The charger considers the actual states of the AC and DC charging outlets, dynamically
calculates and sends back to ELMS the minimum power limit that can be achieved
(G_Power_Min). If ELMS sends a limit below this value, it is neglected. The value is 1.5 kW if
no charging is active, and increases by 4 kW for each active charging port.
• The charger considers the maximum installed AC/DC-converters and the power limit
specied by the SICHARGE D conguration backend (Cong_PowerLimit), and dynamically
calculates and sends back to ELMS the maximum power limit that is possible (G_Power_Max).
• It is expected that ELMS considers abovetwo power limits and prepares the power limit
setpoint to be sent to charger accordingly (G_PowerLimit).
• The charger calculates the internal global power limit (GI_PowerLimit) based on
G_Power_Min, G_Power_Max, G_PowerLimit, Cong_PowerLimit.
• The internal global power limit (GI_PowerLimit) is thereafter split by the charger into
permissible power limits for the AC and DC charging outlets.
• The distribution of power limits for individual DC charging outlets is decided by the charger
internally, based on the allocation of converter groups to that outlet.
• The derived internal power limits for each outlet are rst sent to the connected EV and waits
until the EV communicates the new adjusted target current setpoints to the charger.
The charger reacts to the new EV target current setpoints by adjusting the setpoint to
converters participating in the charging sessions, thereby achieving the power limiting
function.
Note
It is important to consider the fact that the reduction of power from the charger in response to
the reduced power limit setpoint does not take place in the real time system as there are
communication and response delays from EV, and ramp down curves applied by EV or the
charger to adjust to new power limit setpoints, etc.
The ELMS therefore remains a near time system (not real time) in which instantaneous power
reduction or power increase may not always be possible with respect to external specied power
limit setpoints.
External Load Management System
Operating Manual, 07/2022, A5E52045935-AA 7
2.2 Sub-Features
The ELMS has various sub-features which are explained briey in this section. Some of the sub-
features are used by default and are necessary to ensure proper functioning, while some are
options for providing minor functional enhancements.
Power limit handshake
The charger sends the minimum and maximum supported power limits to the ELMS dynamically
over the communication interface. It thereafter expects the ELMS to send back a power limit
setpoint over the communication bus. These three signals form a power limit handshake and are
exchanged in each communication cycle. The power limit setpoint is only considered by the
charger if the load limitation active (ELMS_LLA) ag is set in the control word from ELMS and if
no bus communication error was detected.
Description
2.2Sub-Features
External Load Management System
8Operating Manual, 07/2022, A5E52045935-AA
Power limit fallback
In case of loss of communication detected by the charger and the ELMS, the charger switches to
the power limit fallback setpoint. This signal is sent by the ELMS to the charger via the software
interface. The following diagram depicts the ow of signals related to the power limit fallback
and handshake.
Heartbeat monitoring (optional)
The communication interface relies on TCP protocol which attempts automatic re-connection
and is slow to report communication loss. Heartbeat monitoring is an optional sub-feature and
its main purpose is to have fast and reliable communication loss monitoring.
It needs to be enabled by ELMS via Boolean ag in control word. Once activated, charger
shall send a pulse train of xed on and o duration (e.g., 1 sec. each) as ag in status word.
ELMS needs to send this signal back to Charger via another ag in control word.
In case the heartbeat from ELMS control word stops toggling for a certain duration of time,
charger sets the Heartbeat Error ag in status word and a changover to power limit fallback
occurs.
Description
2.2Sub-Features
External Load Management System
Operating Manual, 07/2022, A5E52045935-AA 9
It is highly recommened to use this sub-feature in cases wherein Modbus polling is done by
ELMS every few hundred millseconds.
Actual EVSE power consumed (optional)
In cases where the charger is equipped with an AC income meter option and there is no error
active in the charger related to a communication loss with this meter, the charger sets the
internal measurement available (IMA) ag in its status word. Once this ag is set, the following
measurements are transferred by the charger to the ELMS:
• actual average EVSE active power (G_APower_Actual)
• **actual average EVSE apparent power (G_SPower_Actual)
• actual voltage L1 line-neutral (U_L1N)
• actual voltage L2 line-neutral (U_L2N)
• actual voltage L3 line-neutral (U_L3N)
• actual powerfactor L1 line (COS_PHI_L1)
• actual powerfactor L2 line (COS_PHI_L2)
• actual powefactor L3 line (COS_PHI_L3)
** available only from SICHARGE FW v2.5.0 and above
In cases where the ELMS has its own energy meter for monitoring the consumed power of
the SICHARGE charger, the external measurements available (EMA) ag can be set in the
control word and the following measurement sent by the ELMS to the charger.
• measured average EVSE active power (EMA_Power)
Outlet power consumption
These are output power consumption of outlets which are transferred from the charger to the
ELMS.
The following data is available for the AC charging outlet power consumption:
• actual average active output power (P_ACx)
• actual AC output current L1 line (I_L1_ACx)
• actual AC output current L2 line (I_L2_ACx)
• actual AC output current L3 line (I_L3_ACx)
The following data is available for the DC charging outlet power consumption:
• atual average active output power (P_DCx)
• actual DC output voltage (U_DCx)
• actual DC output current (I_DCx)
Here x denotes the number of outlets of the type AC or DC. The following diagram depicts
the ow of key signals related to power measurements.
Description
2.2Sub-Features
External Load Management System
10 Operating Manual, 07/2022, A5E52045935-AA
Outlet EV charging states
EV charging states are detected by the charger using the control pilot signal (CP) which is a
hardwired signal for communication between the charger and the EV. These are available for
both AC and DC charging outlets and are transferred by the charger to the ELMS.
Pilot states are enumerated by integer values as shown in the table below.
Table 2-1 Description of Pilot states
State Value Value
A 0 Not connected
B1 1 Connected (EV not ready, EVSE not ready)
B2 2 Connected (EV not ready, EVSE ready)
Description
2.2Sub-Features
External Load Management System
Operating Manual, 07/2022, A5E52045935-AA 11
C1 3 Connected and ready (no ventilation required)
C2 4
D1 5 Connected and ready (ventilation required)
D2 6
E 7 Disconnected
F/Invalid 8 Error: Got no valid pilot state
2.3 Communications
Communications are implemented between SICHARGE and the ELMS using the Modbus TCP
communication protocol. The SICHARGE charger acts as the Modbus server, while the ELM acts
as the Modbus client and initiates queries to the charger. Follow the Operating Instructions to
connect the network cable correctly.
Supported Modbus functions
Modbus function codes supported by the charger are listed in the table below:
Table 2-2 Supported Modbus functions
Function Description
3 Read holding registers
6 Write single register
16 Write mutiple register
Description
2.3Communications
External Load Management System
12 Operating Manual, 07/2022, A5E52045935-AA
Network port forwarding
When multiple SICHARGE chargers are used, they have the same IP address for the PLC. For the
ELMS to communicate with them correctly, the port forwarding concept must be implemented.
The charger consists of the RUT240 router which takes care of this function. An example of this
concept with multiple SICHARGE chargers connected to the ELMS with networking IPv4 address
is show below.
Note
Due to the dierent customer environments, the solution must be parametrized during
commissioning and the load management (client) must implement the mapping of SICHARGE
chargers only.
Description
2.3Communications
External Load Management System
Operating Manual, 07/2022, A5E52045935-AA 13
2.4 Trip line (Emergency loop)
Trip line is a safety feature implemented by using hardwired cables and is important to ELMS
functionality. It is a signal loop connected between the ELMS and safety emergency switch loop
in each SICHARGE charger individually.
The main function of the trip line is to put the charger into the emergency (de-activated)
state in case the charger is not able to maintain the overall incomer active power
consumption below the power limit setpoint for a certain time.
The control logic for the trip line is implemented at the ELMS end and can vary depending on
circumstances. However, it is important to note that once the trip line has been activated, an
emergency stop is initiated by the charger for all AC and DC outlets, and the main incomer
breaker of the charger opens following a delay time.
Check the schematics diagram of the charger to see where to terminate the trip line for the
ELMS in SICHARGE.
A state diagram example for implementation of the trip line is shown below.
Description
2.4Trip line (Emergency loop)
External Load Management System
14 Operating Manual, 07/2022, A5E52045935-AA
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 Modbus registers (write to SICHARGE)
Name Addr Type Factor Units
Control word 1 0 word - -
EVSE active power limit setpoint (G_PowerLimit) 1 uint 100 kW
Measured average EVSE active power (EMA_Power) 2 uint 100 kW
Fallback power limit setpoint (G_FallbackPLim) 3 uint 100 kW
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 ag for ELMS. The power limit setpoints sent via the ELMS are only taken
into account if this ag is set. It is essential to keep this ag set to "true" to ensure correct
working of the feature. If this ag 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 ag to "false" when the trip
line is activated via the hardwired signal (normally closed -> open); otherwise ensure this
ag 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 ag 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 satised, then ensure this ag 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 ag to "true" if this feature is supported by the
controller at the ELMS end; otherwise ensure this ag is set to "false".
• Bit 15 – Heartbeat ELMS (HB_ELMS)
Returns heartbeat pulses from the ELMS to SICHARGE. This ag 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 ag.
Description
2.5Modbus registers (ELMS to SICHARGE)
External Load Management System
Operating Manual, 07/2022, A5E52045935-AA 15
EVSE active power limit setpoint (G_PowerLimit)
Main power limit setpoint for SICHARGE in cases where the ELMS feature is active (ELMS_LLA =
true) and no communication loss is detected between SICHARGE and ELMS.
Measured average EVSE active power (EMA_Power)
Measures the average active power consumed by SICHARGE on an external energy meter
installedat the ELMS end.
Fallback power limit setpoint (G_FallbackPLim)
Fallback power limit setpoint for SICHARGE in cases where a communication loss is detected
between SICHARGE and ELMS.
2.6 Modbus registers (SICHARGE to ELMS)
SICHARGE has all Modbus registers as Holding registers. Floating point values are transmitted as
integers after applying a scaling factor to shift decimal places. These registers can be written by
ELMS via Modbus TCP Communication. Mappings are shown in table below.
Name Addr Type Factor Units
Interface Status and Errors
Status Word 1 10 word - -
Error Word 1 11 word - -
Mains Power parameters
Min EVSE Power (G_Power_Min) 15 uint 100 kW
Max EVSE Power (G_Power_Max) 16 uint 100 kW
Actual Average EVSE Active Power (G_APower_Actual) 17 uint 100 kW
EVSE Active Power Limit (G_Power_Limit_active) 18 uint 100 kW
Actual voltage L1 Line-Neutral (U_L1N) 19 uint 100 V
Actual voltage L2 Line-Neutral (U_L2N) 20 uint 100 V
Actual voltage L3 Line-Neutral (U_L3N) 21 uint 100 V
Actual power factor L1 Line (COS_PHI_L1) 22 uint 10000 -
Actual power factor L2 Line (COS_PHI_L2) 23 uint 10000 -
Actual power factor L3 Line (COS_PHI_L3) 24 uint 10000 -
**Actual average EVSE apparent power (G_SPower_Actual) 25 uint 100 kVA
AC1 Outlet status and measurements
PilotState 30 uint - -
Actual output current L1 Line (I_L1_AC1) 31 uint 100 A
Actual output current L2 Line (I_L2_AC1) 32 uint 100 A
Actual output current L3 Line (I_L3_AC1) 33 uint 100 A
Actual average active Output Power (P_AC1) 34 uint 100 kW
DC1 outlet status and measurements
Description
2.6Modbus registers (SICHARGE to ELMS)
External Load Management System
16 Operating Manual, 07/2022, A5E52045935-AA
Name Addr Type Factor Units
Pilot state 40 uint - -
Calculated average active output power (P_DC1) 41 uint 100 kW
Actual DC output voltage (U_DC1) 42 uint 10 V
Calculated DC output current (I_DC1) 43 uint 100 A
DC2 outlet status and measurements
Pilot state 45 uint - -
Calculated average active output power (P_DC2) 46 uint 100 kW
Actual DC output voltage (U_DC2) 47 uint 10 V
Calculated DC output current (I_DC2) 48 uint 100 A
DC3 outlet status and measurements
Pilot state 50 uint - -
Calculated average active output power (P_DC3) 51 uint 100 kW
Actual DC output voltage (U_DC3) 52 uint 10 V
Calculated DC output current (I_DC3) 53 uint 100 A
DC4 outlet status and measurements
Pilot state 55 uint - -
Calculated average active output power (P_DC4) 56 uint 100 kW
Actual DC output voltage (U_DC4) 57 uint 10 V
Calculated DC output current (I_DC4) 58 uint 100 A
** available only from SICHARGE FW v2.5.0 and above
Note
The query of register address which appears as a gap in the above table would not elicit an error
response from the Modbus communication protocol. These addresses are reserved for future
use. If the ELMS controller supports Modbus function code 16 (read multiple registers), then it
is recommended to raise a single query to read registers from addresses 10 to 58 in order to
ensure ecient communication and ignore the values of registers which are not required.
Description
2.6Modbus registers (SICHARGE to ELMS)
External Load Management System
Operating Manual, 07/2022, A5E52045935-AA 17
Status word 1
The bit-wise split of the status word from SICHARGE to the ELMS and its description are discussed
below. Note that in this case LSB is Bit 0 and MSB is Bit 15.
• Bit 00 – Charger Ready (CH_Rdy) SICHARGE sets this ag to true when it is ready for charging;
otherwise it is set to false. The charger is ready only when all of the following conditions are
satised:
– Charger operation state is "Running”
– Main breaker is switched ON
– Safety relay is not activated.
Please note that activation of the hardwired trip line TRIP Line from the ELMS would result in
the safety relay being activated in the charger and this ag being reset to False.
• Bit 01 – AC1 Ready (AC1_Rdy)
SICHARGE sets this ag to true when the AC1 outlet is ready for charging with no active
errors; otherwise it is set to false.
• Bit 02 – AC1 EV Connected (AC1_EV_Con)
SICHARGE sets this ag to true when the EV connection is detected at the AC1 outlet i.e.,
when the pilot state is between A and E (both not inclusive); otherwise it is set to false.
• Bit 03 – DC1 Ready (DC1_Rdy)
SICHARGE sets this ag to true when the DC1 outlet is ready for charging with no active
errors; otherwise it is set to false.
• Bit 04 – DC1 EV Connected (DC1_EV_Con)
SICHARGE sets this ag to true when the EV is connected to the DC1 outlet and is waiting in
the cable check phase with authentication done. SICHARGE sets this ag to false when the
charging phase is no longer active at this outlet.
• Bit 05 – DC2 Ready (DC2_Rdy)
SICHARGE sets this ag to true when the DC2 outlet is ready for charging with no active
errors; otherwise it is set to false.
• Bit 06 – DC2 EV Connected (DC2_EV_Con)
SICHARGE sets this ag to true when the EV is connected to the DC2 outlet and is waiting in
the cable check phase with authentication done. SICHARGE sets this ag to false when the
charging phase is no longer active at this outlet.
• Bit 07 – DC3 Ready (DC3_Rdy)
SICHARGE sets this ag to true when the DC3 outlet is ready for charging with no active
errors; otherwise it is set to false.
• Bit 08 – DC3 EV Connected (DC3_EV_Con)
SICHARGE sets this ag to true when the EV is connected to the DC3 outlet and is waiting in
the cable check phase with authentication done. SICHARGE sets this ag to false when the
charging phase is no longer active at this outlet.
• Bit 09 – DC4 Ready (DC4_Rdy)
SICHARGE sets this ag to true when the DC4 outlet is ready for charging with no active
errors; otherwise it is set to false.
Description
2.6Modbus registers (SICHARGE to ELMS)
External Load Management System
18 Operating Manual, 07/2022, A5E52045935-AA
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