Hardware

The following figure shows a block diagram of CMM-IV and its external connections

General setup:

• CMM-IV needs 12…24V power supply on PWR-CON/GND-CON
• The CMM-IV current path must be connected in series to the DUT as illustrated in figure 1.

The measurement values can be read using one of the following possibilities:

• Ethernet TCP-Connection
  • Continuous High-Speed-Streaming with 125 kS/s
  • Text-Based-Protocol with Init-, Trigger- and Fetch-Command
• CAN
  • Cyclic Message (configurable ID and period) which contains the average value
  • ISO-TP-Protocol to read average, minimum and maximum value

Additional features are:

• The module can be configured via ethernet (CMM-IV-GUI or DLL) or CAN (ISO-TP protocol)
• Permanent parameter storage of the configuration in flash memory
• Calculation of average, minimum and maximum values
• The current path is electrically isolated from electronics supply and digital IO (up to 150V)
• Detection of reverse current

1.1Connector Pinning

1.1.1System connector

1.1.2CAN Front Connector

The CAN front connector is a standard female D-Sub 9 (DE-9) connector.

1.1.3Ethernet Front Connectors

The CMM-IV has two Ethernet ports and an integrated switch. This allows easy wiring without the need of an additional switch. Use CAT5e or CAT6 cables for wiring.

1.1.4Mating system connector

The following components may be used for the mating connector on the test system. One connector with 8 high current pins is needed. Different versions for crimping or soldering from two manufacturers can be found in the following table.

1.1.5Dimensions

CMM-IV is designed on a 160mm x 100mm Euro card, including front cover with a width of 25.4mm (5HP) and a standard DIN41612 connector. With these dimensions it fits in standard 19” / 3HU carriers and racks.

1.2Technical data

1.2.1Ambient conditions

1.2.2Current Path

Depending on the applied currents, the measurement current path must be wired with a low resistance to maintain low voltage drops. I.e. use short wires and as many high-current pins as possible – both for current input and current output.

Each high-current pin may carry up to 40A DC maximum. The more high-current pins (with wires of high diameter) are used, the lower the voltage drop and temperature of CMM-IV.

1.2.3Module Supply

Connect the power supply for CMM-IV between PWR-CON and GND-CON. It is strongly recommended not to use the DUT power supply to power the CMM-IV.

Note that the current path is disconnected, when no power is applied.

Typical current consumption

1.2.4DC Accuracy

Accuracy of the module is verified for DC currents. Each module passes a calibration procedure at IRS. The module may of course be re-calibrated. See Calibration Recommendation for recommendations.

1.2.5DC Voltage Drop

Voltage drop is the voltage between current input and output, measured on the module connector. The drop on the mating power connector pins and the wiring is not included in the following values.

1.2.6On/Off Interface

The digital input On/Off can be used to switch the current path of the CMM-IV on or off.

1.2.7LED Range Indicator

The CMM-IV (version of 1.3 and above) is equipped with a LED range indicator which is located close to the heat sink on the component side of the CMM-IV. See Figure 3 for details.

1.2.8CAN Interface

The integrated CAN interface is a High-Speed CAN interface with FD-Support.

For further details, see datasheet of TCAN332 and System Integration – CAN.

1.2.9Ethernet-Interface

The CMM-IV is equipped with a 3-port Gigabit-Ethernet Switch. Two ports of the switch are connected to RJ45 jacks on the front panel. The third switch is connected to the microcontroller of the CMM IV. The connection between the switch and the microcontroller is limited to 100 Mbit/s.

For further details, see datasheet of KSZ9893RNX and System Integration – Ethernet connection.

1.3System Integration

The following section describes hardware prerequisites of the communication interfaces. For integration of the current path and the power supply, see the remarks in the technical data.

1.3.1CAN

The High-speed CAN interface may be used to read measurement data.

Any High-Speed CAN interface from any vendor may be applied as counterpart for data acquisition. Make sure that termination of the entire bus is implemented properly with two 120 Ohm resistors at the respective far ends of the bus. No other termination resistors are included.

It is recommended to use a twisted pair with an impedance of 120 Ohm. Do not forget the GND connection. It is recommended to use the front D-Sub 9 connector for CAN communication because it uses GND-EXT which is directly connected to the CAN transceiver. GND-CON on the system connector is connected to GND-EXT and the CAN transceiver through an EMI filter which can lead to signal integrity problems especially at high baud rates.

Every CMM on the bus must run at the same baud rate and use different CAN IDs. CAN ID and baud rate may be configured via TCP-Text-Protocol or via CAN ISOTP and are stored permanently in flash memory.

For integration as a single module in a test system setup, please add a CAN counterpart with a termination resistor of 120 Ohm. CMM-IV includes 120 Ohm -termination which can be enabled or disabled by software.

If several CMM-IV are connected to the same CAN interface the termination resistor of each CMM-IV must be disabled. A single termination must be included at the far end of the CAN bus.

1.3.2Ethernet connection

The IP address can be configured in the GUI described in Configuration tool CMM-IV-GUI. Furthermore, the IP can be modified with a dip switch on the CMM-IV (see Figure 4). An offset between 0 and 6 is added, depending on the position of the switch. If all three switches are in the ON position the CMM IV uses its default IP which is 192.168.222.21.

Examples: