MCS (ISO 15118-20 over 10BASE-T1S) Runbook

The Megawatt Charging System (MCS) carries ISO 15118-20 high-level communication over a 10BASE-T1S data link instead of powerline communication. ChargeLink runs an MCS session as an ISO 15118-20 DC session that selects the MCS energy service (ServiceID 8), with external identification (EIM), in the Scheduled control mode, over TLS only, in the charger (SECC) and the vehicle (EVCC) role. The connector signals (CE and ID) come from ChargeLink's simulated coupler model and travel over the coupler link, a ChargeLink interface on TCP port 50119 of the same 10BASE-T1S cable. Because the coupler link is ChargeLink's own interface, both roles in this release run against the other ChargeLink role, not against a third-party device (see Limits).

The MCS session uses the DC messages of ISO 15118-20. What MCS adds in ChargeLink:

• The data link first. The charger answers SDP discovery only once the data link is ready (the EV is present on the coupler link and the connector reads as mated).
• Connector checks. The charger answers the cable check only with the CE state C measured, and welding detection and the session stop only with CE state B. The EV closes its switch before the cable check and opens it after the stop.
• Side-B voltage check. On a plant-coupled charger, the schedule exchange is finished only when the plant's side-B voltage allows it; until then the charger answers Ongoing and the EV repeats its request.
• MCS limits. The charger's start check accepts the MCS voltage and current range (see Limits).

The kit has a charger\ and a vehicle\ folder.

Before you start

Complete the preflight for the 10BASE-T1S interface on each PC. Then note, on each PC:

Get-NetAdapter | Format-Table Name, ifIndex, Status, InterfaceDescription
Get-NetIPAddress -AddressFamily IPv6 -InterfaceIndex <T1S_IFINDEX> | Where-Object { $_.IPAddress -like 'fe80*' }

You need the charger's 10BASE-T1S link-local address and the 10BASE-T1S interface index of each PC. Windows can renumber interfaces after a restart or a re-plug, so read the index again before each bench day.

Set up the network

1. Connect the two adapters with the 10BASE-T1S cable and apply the PLCA settings above on both PCs.
2. Check the link: both interfaces show Up, and each PC reaches the other's link-local address on the 10BASE-T1S interface (for example ping fe80::<CHARGER_ADDRESS>%<LOCAL_T1S_IFINDEX> from the EV side; the zone index is always the local PC's interface index).
3. On the charger side, an administrator adds three inbound Allow rules for the charger's chargelink.exe, limited to the 10BASE-T1S interface and to link-local remote addresses (fe80::/10): UDP 15118 (SDP), TCP 50118 (the TLS session) and TCP 50119 (the coupler link). The EV side opens outbound connections only.

$Exe = '<KIT>\charger\bin\chargelink.exe'
$T1s = '<CHARGER_T1S_ADAPTER_NAME>'
New-NetFirewallRule -DisplayName 'ChargeLink MCS SDP'          -Direction Inbound -Action Allow -Program $Exe -Protocol UDP -LocalPort 15118 -InterfaceAlias $T1s -RemoteAddress 'fe80::/10'
New-NetFirewallRule -DisplayName 'ChargeLink MCS session'      -Direction Inbound -Action Allow -Program $Exe -Protocol TCP -LocalPort 50118 -InterfaceAlias $T1s -RemoteAddress 'fe80::/10'
New-NetFirewallRule -DisplayName 'ChargeLink MCS coupler link' -Direction Inbound -Action Allow -Program $Exe -Protocol TCP -LocalPort 50119 -InterfaceAlias $T1s -RemoteAddress 'fe80::/10'

Add the rules before the charger runs for the first time. If Windows shows a Windows Security Alert for chargelink.exe, see Troubleshooting.

Protocol and profile per role

The protocol and the profile must agree: an mcs charger runs only with a runtime profile whose energy service is mcs, and such a runtime profile runs only under --protocol mcs. Without the MCS settings, the EV runs a plain ISO 15118-20 DC session, unchanged.

ChargeLink as charger

The MCS charger is plant-coupled: it computes every response from the session and the plant model, reads the plug-in state from the plant and shows the connector signals on the operator screen. It answers SDP only after an EV has connected to its coupler link, so in this release its peer is the ChargeLink EV (see Limits). On the NI VeriStand bench the bench software starts it for you. Install and activate the bench first (Set Up the VeriStand Bench), with the 10BASE-T1S adapter as the bench interface.

1. Open PowerShell as administrator in the kit's charger folder (charger\) and start the operator with the MCS stack:

   .\Start-ChargeLinkVeriStand.ps1 -Stack Mcs

   VeriStand opens with the ChargeLink screen. The run folder records which plant model, EV case and operating point the charger was started with (demo-plant.json).
2. On the screen press, in this order: Apply safe startup, Start session, Start external EVCC. Wait until the screen shows that the external EVCC session runs.
3. Start the EV (see ChargeLink as vehicle).
4. On the screen's MCS page press Plug inserted. The page shows the CE state, the ID state and D-LINK_READY from ChargeLink's coupler model. The charger answers discovery only after the EV has connected to the coupler link and D-LINK_READY is shown.
5. Finish and stop the session as on the NI VeriStand Bench page.

For reference, the bench software starts the charger with settings equivalent to the following; operators do not type this command.

$Data      = 'C:\ChargeLinkData'
$Run       = "mcs-$(Get-Date -Format yyyyMMdd-HHmmss)"
$IfIndex   = <CHARGER_T1S_IFINDEX>
$Advertise = 'fe80::<CHARGER_T1S_ADDRESS>%' + $IfIndex
$Pki       = "$Data\pki"
$env:CHARGELINK_ISO20_RUNTIME_PROFILE = '<KIT>\charger\config\mcs_runtime_profile.json'

chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json evse start --external-evcc-session --run-id $Run `
  --protocol mcs --profile-id mcs_reference_bench --exi-mode chargelink-exi `
  --host '::' --tcp-port 50118 --udp-port 15118 `
  --advertise-ipv6 $Advertise --interface-index $IfIndex `
  --tls --tls-cert "$Pki\secc-chain.pem" --tls-key "$Pki\secc-key.pem" --tls-cafile "$Pki\v2g-root-ca.pem" --require-ca `
  --plant-grpc-endpoint <PLANT_ENDPOINT> --requested-power-kw 1250 --target-voltage-v 900

• The coupler link listens on TCP 50119 on the charger's listen address. --advertise-ipv6 and --interface-index name the charger's 10BASE-T1S interface; without them a non-loopback charger refuses to start.
• The kit's MCS runtime profile offers the Scheduled control mode with one 300 s charging schedule. On a bench with the DC plant model instead of the MCS plant model, the kit falls back to the DC operating point and a 60 s schedule, and labels the run as a DC-power fallback.
• The charger's stated maxima default to the operating point (--requested-power-kw, --target-voltage-v). --evse-rated-current-a and --evse-rated-voltage-v state a higher rating for a plant-coupled charger; the start check refuses a rating below the operating point, a voltage above 1250 V and a current above 3000 A.
• A charger started without a plant endpoint does not run the MCS runtime: it offers the DC service only, and its evidence says so (see Results and evidence).

A good session: the coupler record shows the EV on the coupler link, D-LINK_READY and the first SDP request answered, and the charger's evidence ends with evidence_status: passed and offered_service_id 8.

ChargeLink as vehicle

The EV is the ISO 15118-20 DC EVCC with the MCS energy service. It connects to the charger's coupler link, waits for D-LINK_READY, then runs SDP on the 10BASE-T1S interface, TLS and the MCS session. The coupler link is required, so in this release its peer is the ChargeLink MCS charger (see Limits). Choose the EV case that fits the charger's operating point, as named in the charger's demo-plant.json:

In a normal (not elevated) PowerShell window on the ChargeLink PC, in the kit's vehicle folder (vehicle\):

$Data       = 'C:\ChargeLinkData'
$IfIndex    = <LOCAL_T1S_IFINDEX>
$ChargerT1s = 'fe80::<CHARGER_T1S_ADDRESS>'
$Coupler    = '[' + $ChargerT1s + '%' + $IfIndex + ']:50119'
$Tls        = '<KIT>\vehicle\tls'
$env:CHARGELINK_ISO20_LIVE_SEMANTIC_CASE        = '<KIT>\vehicle\cases\<EV_CASE>.json'
$env:CHARGELINK_ISO20_FULL_WIRE_SESSION_MANIFEST = '<KIT>\vehicle\cases\full-wire-session-manifest.json'

chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json evcc activate-profile `
  --protocol iso15118-20 --profile-id iso15118_20_dc_evcc_reference `
  --use-sdp --interface-index $IfIndex --tcp-port 50118 --connect-timeout-ms 5000 --exi-mode chargelink-exi `
  --tls --tls-cert "$Tls\vehicle-cert-chain.pem" --tls-key "$Tls\vehicle-key.pem" --tls-cafile "$Tls\v2g-root-ca.pem" --require-ca `
  --max-steps 14 --requested-power-kw 80 `
  --energy-service mcs --mcs-coupler-link $Coupler

Start order: either side may start first. The EV retries the coupler link and waits up to 30 s for it and for D-LINK_READY; after that it ends with mcs_d_link_not_ready, and you start it again. Press Plug inserted on the charger's screen within that time.

The EV's exit code says whether the command ran, not whether the MCS session completed. Read the verdict from the evidence. A good session ends with a last coupler-record line of kind outcome and value mcs_session_completed.

Results and evidence

Each role writes its run directory as for ISO 15118-20 (frame trace, TLS and SDP diagnostics, manifest; see ISO 15118-20 and Trace, Evidence and Reports). MCS adds the files below.

A completed MCS session shows, on the charger, evidence_status: passed with offered_service_id 8, and, on the EV, a last line with kind outcome and value mcs_session_completed. The order of events in the two coupler records is: the EV on the coupler link, D-LINK_READY, the first SDP request answered, the EV's switch closed and CE state C before the cable check, the switch opened and CE state B before welding detection.

Limits

• The MCS charger connects to the ChargeLink EV. The charger answers SDP only after an EV is present on its coupler link, and the coupler link is a ChargeLink interface. A third-party MCS vehicle or EVCC is not supported as a device under test in this release.
• The MCS EV connects to the ChargeLink charger. The EV requires --mcs-coupler-link and waits for D-LINK_READY on it before SDP. A third-party MCS charger or SECC is not supported as a device under test in this release.
• The charger runs on the NI VeriStand bench. The MCS runtime needs the plant-coupled charger; a charger without a plant endpoint offers the DC service only.
• Scheduled control mode only. MCS sessions over 10BASE-T1S use the Scheduled control mode; the VeriStand bench's MCS charger offers Scheduled only. ChargeLink does not offer MCS Dynamic control over 10BASE-T1S.
• Simulated connector signals. CE and ID come from ChargeLink's coupler model and travel over the 10BASE-T1S cable on the coupler link, not over a real MCS connector, so losing the data link also drops CE and ID. The coupler link is a ChargeLink interface, not part of the standard; it runs over plain TCP, not TLS, for a closed bench network. Both ends must come from the same release. Each loss of the coupler link is recorded on both sides.
• Link detection. The 10BASE-T1S link counts as usable while the EV is present on the coupler link; Windows gives ChargeLink no "Ethernet operational" signal from the adapter.
• 10BASE-T1S physical layer. The link layer between two PCs is used with PLCA node 0 on the charger side and node 1 on the EV side, node count 8. The end termination and the IEEE 802.3 clause 147/148 physical layer are not covered.
• ISO 15118-10 timers and retries are not implemented: connection resume, the retries, the init retries and the emergency stop on link loss. A link loss inside a session ends it through the coupler-link loss; it is not judged against the ISO 15118-10 timing. The EV waits for D-LINK_READY within a plain 30 s bound.
• Pause. The ChargeLink charger never asks the EV to pause. The EV ends the session when a charger asks for a pause.
• The MCS demo EV case charges for about 240 s near 1388 A and needs a Scheduled charger at 1250 kW / 900 V with a schedule of at least 300 s. At 1000 kW / 900 V the charger offers 1111 A, and the EV stops at ChargeParameterDiscovery.
• A charger without the ISO 15118-20 runtime (the reference-responder listener) offers the DC service only. Its MCS evidence then says iso20_dc_exchange_only_not_mcs, so a DC exchange never reads as an MCS result.
• No power hardware. The plant is a simulation: no CE/ID circuit, no coupler, no real power, no thermal or cable-temperature model.
• No conformance claim. A ChargeLink MCS result is engineering evidence, not an MCS conformance or certification statement.
• Not provided: Plug & Charge, bidirectional power transfer (including MCS BPT), standby, and EV auxiliary power.

See also ISO 15118-20 for the TLS and session rules MCS shares with DC, and Capability Boundaries.

Troubleshooting

For general failures (licence, TLS, ports, VeriStand) see Troubleshooting.