## 6 Testing System  
This section describes the structure of the testing system in Figure 3. The testing system consists of a PC and electric load, and both of them together represent the EV in a real-world charging process. The EVSE, the EV charger which is the system under test (SUT), is connected to the testing system. The EVSE has two pins for power delivery to the electric load, two for CAN communication via the CAN bus, and two for the Pilot and Wake-up signals, respectively. Especially CW-DIO32 [18], an I/O board, is utilized for communication of the Pilot and Wake-up signals between the EVSE and the PC as shown in Figure 2.  
Figure 2: _Cont._  
Figure 2: Flow diagram of a normal charging sequence.  
CW-DIO32 uses RS-485 and Modbus protocol in connecting with other devices. It works with 12-24 VDC and has 16 input and 16 output points with four commons. In addition, the relay coil, which enables power transfer from the EVSE to the load, is connected to the output port of the board. The PC runs as a tester, monitoring and administering the whole testing procedure. It also manages CW-DIO32 and the electric load. Inside the PC, it contains two applications: CANoe and test manager.  
CANoe is the main part of the testing system; it is the only part that has the privilege of giving orders and processing the received data. In contrast, the rest of the equipment is subjected to the CANoe instructions. CANoe runs a program written in CAPL. This program has two parts: the test case runner and port out. The test case runner performs a set of test cases while the port out is responsible for connecting CANoe with the RS232 bus whenever it is required. CANoe is connected directly to the EVSE through the CAN bus and to the test manager in the PC via the virtual RS232 bus.  
The test manager is an application written in C#. It handles the electric load and the CW-DO32 board. Therefore, it contains the load manager and the I/O board manager as well. The load manager provides the load with an interface to configure it and to switch the charging modes of the electric load between constant volt (CV) and constant current (CC). It also monitors the input voltage of the electric load. On the other hand, the I/O board manager is used to control and monitor the CW-DIO32 manager. It enables us to observe the Pilot and Wake-up signals, and the status of the relay coil. During the testing, real components have been used. The EVSE is manufactured by PNE solution, Co, Ltd., Gyeonggi-do, and the DC electronic load by Chroma Systems Solutions. The testing system has been developed and tested in the KTL (Korean Testing Laboratory) as shown in Figure 4.  
Figure 3: Physical and logical connection between components in the testing system.  
The system secures the electric power connection using a relay. By default, the relay is set to off unless it gets a command from CANoe to turn on. As shown in Figure 3, CANoe has a virtual RS232 to communicate with the test manager which, in turn, controls the relay through CW-DIO32 via the RS485 bus. In cases where there is an error, such as getting a fault message or the test device CAN controller is forced into a bus off state, CANoe switches the relay off to save the system from being at risk.  
Figure 4: The testing system components.  
Figure 5: Main window of the test manager.  
Conformance testing of EVSE can be performed in the test manager by choosing a desired testing mode. When the testing start button is pressed, CANoe begins running the testing process. The set of test cases is extracted from the SGSF-064-1 and written in CAPL. There are four testing modes or scenarios as depicted in Figure 5. The following are the testing modes.