Table of Content

• Introduction 
• About ChargePilot
• Technical Setup
• Modbus Logic
  • Read Only Mode 
  • Read/ Write Mode 
  • Site Integrated Load Management 
  • Fallback Values 
    • EMS Offline
    • Charger Offline
• About the Modbus TCP/ IP Interface 
• Register Tables
  • Total Live Values
  • Administration
  • Set Grid Values
  • CP Live Values 

Introduction 

The following Modbus register table gives an overview of the Modbus TCP/ IP connection between an Energy Management System (EMS) and ChargePilot’s Smart Charging Local Controller (LC). LC thereby always acts as a server for the Energy Management System. The LC acts as a client for the energy meter.  

Figure 1: Modbus Interface Landscape

Figure 2: Modbus Interface Control Architecture

About ChargePilot

The following schematic shows the general role and outlines the supported interfaces of the Charging and Energy Management ChargePilot by The Mobility House. The LC is locally connected (over Ethernet/OCPP) to the operated charging stations and acts as their backend. More Information about ChargePilot can be found here. 

Figure 3: ChargePilot Interface Landscape
 

Technical Setup

The Modbus interface is by default deactivated. If you are interested in using the feature, please contact your customer success manager at The Mobility House. 

If enabled, you can connect to one of the ethernet ports on the Smart Charging Controller (Port A (charging stations) or Port B (internet connection)) and can be accessed via the IP and the Slave ID 1. 

If connected to the customer's Internet and the same customer network as the Modbus client, the physical setup of ChargePilot is consistent with the normal pre-commissioning guidelines found on our website. If not using the customer’s internet, a port on the charger ethernet switch will need to be reserved to connect to the customer’s controller. 

If you have any questions on the setup of ChargePilot, please contact our technical team.

Modbus Logic

Read Only Mode 

If the Modbus interface is activated in Read only-Mode most registers can be read, but holding registers are not accessible (chapter Set Grid Values). All registers marked with a star in the table, are only available if the LC is connected to the ChargePilot meter. 

Read/ Write Mode 

If the Modbus interface is activated in Read/Write-Mode, also the holding registered are accessible. 

The register 81XX sets absolute values for power (8192). While power settings are equally distributed on the connected phases, the current settings are to be set per phase.

Example: If a value of 30.000 is set, the maximum power of each phase is 10 kW. 

By setting a value in Register 8200 “Grid Limit for all CPs in % of the physical maximum set by Administrator” the available power/current on each phase for the charging infrastructure will be reduced, to the set percentage.    
 Example: If the limit is 100 A per phase and a value of 60 is set, the maximum current per phase is 60 A. 

Site Integrated Load Management 

ChargePilot can also be operated with site integrated load management logic and Modbus. In this case, a meter is installed at the grid connection point to measure the building load and the residual power is distributed to the charging infrastructure. In this case, the Modbus interface can still operate in Read/Write-Mode. The additional limit set by the values of register 81XX is taken into account in addition to the restrictions given by the building load measured by meter.

Figure 4: Site Integrated Load Management

If Site Integrated Load Management load management logic is active, the Modbus interface can only be operated in Read Only-Mode! 

Fallback Values 

For the Modbus interface the following two fallback scenarios need to be considered

EMS Offline

In Read/Write mode (= external limits are received via the Modbus interface) the Modbus client (e.g. a EMS) sending limits becomes offline. 

In this situation, a fallback value for the total site power will be set during setup of the interface. The logic will operate in fallback mode, after a configurable period (default is 30s), without receiving a signal on any of the holding register. The fallback value for the limit of the charging infrastructure and the interval can be adjusted during the implementation of your system. 

Charger Offline

Whenever the charger loses connection to ChargePilot a predefined fallback value can be set individually for each charger. Whenever the charger appears offline in ChargePilot the charger can still charge with the fallback value. Furthermore, ChargePilot does not need to block/reserve the full capacity of charger. Example in the graphic below.

Figure 5: Fallback

About the Modbus TCP/ IP Interface 

This document describes the behavior of the TMH Controller in case it is configured as Modbus TCP/IP server. In this mode, the TMH Controller is passively providing its metering data upon request to the devices which query the TMH Controller. Additionally, the client controller (customer’s controller) can write some configs in the Holding registers, if the feature is activated. 

Special note for registers with a size of more than 16 bits:  

Registers of such types are composed of standard 16-bit Modbus registers. Most-significant bits are located in registers with lower addresses, least-significant bits are stored in registers with higher addresses. 

Example: Assume a virtual register (uint32) is placed at offset 0x1000. This register should reflect 2,293,828 operating hours. Address 0x1000 contains 0x23 and address 0x1001 contains 0x44. During transmission both registers are transferred in network byte order (Big Endian) as required by the Modbus specification, i.e. a “Read Holding Registers” for both registers shows up as 0x00 0x23 0x00 0x44 on the wire. 

Register Tables

Total Live Values

The following table shows registers containing live data of the entire site. 

Note: Holding registers are the read/write registers, Input registers are the read registers 

*Only available if the separate meter is connected to ChargePilot

Administration

The following table shows administration registers containing general information about the site.

Note: Holding registers are the read/write registers, Input registers are the read registers 

*Only available if the separate meter is connected to ChargePilot 

Set Grid Values

The following table shows holding registers to set an external grid limit for the entire ChargePilot site.

Note: Holding registers are the read/write registers, Input registers are the read registers 

*Only available if the separate meter is connected to ChargePilot 

CP Live Values 

The registers of the following section allows live data to be read for each connector. The following values are identical for connector 2 and so on with a gap of 256 (dec) or 100 (hex). So, the registers for connector 2 will start at 12560 or 0x3110, connector 3 at 12816 or 0x3210, and so on. Please note that the order of the CPs can change whenever chargers are added or removed from the site configuration. 

Note: Holding registers are the read/write registers, Input registers are the read registers 

*Consumed energy of an active charging session (4294967295 = no active charging session) 

**Only available if provided by the charger (4294967295 = not provided by the charger)