MAXIM 78M6618 User Guide
78M6618 PDU1 Evaluation Board
User Manual
November 2011
Rev 3
UM_6618_022
78M6618 PDU1 Evaluation Board User Manual UM_6618_022
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit
patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408- 737- 7600
2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products.
UM_6618_022 78M6618 PDU1 Evaluation Board User Manual
Table of Contents
1 Introduction.................................................................................................................................... 5
1.1 Package Contents................................................................................................................. 5
1.2 System Requirements ........................................................................................................... 5
1.3 Safety and ESD Notes .......................................................................................................... 6
1.4 Firmware Demo Code Introduction ........................................................................................ 6
1.5 Testing the Evaluation Board Prior to Shipping ...................................................................... 6
2 Installation ..................................................................................................................................... 7
2.1 USB Connection and Driver Installation ................................................................................. 8
2.2 Connecting the External DC Supply ...................................................................................... 8
2.3 Confirm COM Port Mapping .................................................................................................. 9
2.4 Verify Serial Connection to the PC ...................................................................................... 10
2.5 Connect the AC Source and Load ....................................................................................... 12
3 Circuit Description and Theory of Operation ............................................................................. 13
3.1 78M6618 ............................................................................................................................ 13
3.2 Voltage Regulators ............................................................................................................. 13
3.3 Input Signal Conditioning .................................................................................................... 14
3.4 Relay Control ...................................................................................................................... 14
3.5 Theory of Operation ............................................................................................................ 14
3.5.1 78M6618 Operation ................................................................................................... 14
3.5.2 Voltage and Current Measurement ............................................................................ 14
4 In-Circuit Emulator (ICE) Adaptor ............................................................................................... 17
5 Schematics, Bill of Materials, and PCB Layouts ........................................................................ 18
5.1 78M6618 PDU1 Evaluation Board Schematics .................................................................... 18
5.2 78M6618 PDU1 Evaluation Board Bill of Materials .............................................................. 22
5.3 78M6618 PDU1 Evaluation Board PCB Layouts.................................................................. 25
6 Ordering Information ................................................................................................................... 26
7 Contact Information ..................................................................................................................... 26
Appendix A - 78M6618 PDU1 Board with CTs .................................................................................... 27
A.1 78M6618 PDU-CT Evaluation Board ................................................................................... 27
A.2 78M6618 PDU-CT Evaluation Board Schematics ................................................................ 28
A.3 78M6618 PDU-CT Evaluation Board Bill of Materials .......................................................... 32
A.4 78M6618 PDU-CT Evaluation Board PCB Layouts .............................................................. 34
Appendix B – 78M6618 PDU1 Version 1 (Single-Ended Shunt) ......................................................... 36
Revision History .................................................................................................................................. 37
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Figures
Figure 1: 78M6618 PDU1 Connections .................................................................................................... 7
Figure 2: Serial Port Verification Screen ................................................................................................. 12
Figure 3: Differential PDU Block Diagram............................................................................................... 13
Figure 4: PCB Parasitic Resistance ....................................................................................................... 15
Figure 5: Differential Amplifier and Current Sense Resistor .................................................................... 15
Figure 6: Detail View of Differential Amplifiers ........................................................................................ 16
Figure 7: ICE Adaptor ............................................................................................................................ 17
Figure 8: 78M6618 ICE Adaptor Attachment .......................................................................................... 17
Figure 9: 78M6618 PDU1 Evaluation Board Electrical Schematic (1 of 4) ............................................... 18
Figure 10: 78M6618 PDU1 Evaluation Board Electrical Schematic (2 of 4) ............................................. 19
Figure 11: 78M6618 PDU1 Evaluation Board Electrical Schematic (3 of 4) ............................................. 20
Figure 12: 78M6618 PDU1 Evaluation Board Electrical Schematic (4 of 4) ............................................. 21
Figure 13: 78M6618 PDU1 Evaluation Board PCB Top View ................................................................. 25
Figure 14: 78M6618 PDU1 Evaluation Board PCB Power View.............................................................. 25
Figure 15: 78M6618 PDU1 Evaluation Board PCB GND View ................................................................ 25
Figure 16: 78M6618 PDU1 Evaluation Board PCB Bottom View ............................................................ 25
Figure 17: 78M6618 PDU-CT Evaluation Board ..................................................................................... 27
Figure 18: 78M6618 PDU-CT Evaluation Board Electrical Schematic (1 of 4) ......................................... 28
Figure 19: 78M6618 PDU-CT Evaluation Board Electrical Schematic (2 of 4) ......................................... 29
Figure 20: 78M6618 PDU-CT Evaluation Board Electrical Schematic (3 of 4) ......................................... 30
Figure 21: 78M6618 PDU-CT Evaluation Board Electrical Schematic (4 of 4) ......................................... 31
Figure 22: 78M6618 PDU-CT Evaluation Board PCB Top View.............................................................. 34
Figure 23: 78M6618 PDU-CT Evaluation Board PCB Bottom View......................................................... 35
Tables
Table 1: COM Port Setup Parameters .................................................................................................... 10
Table 2: 78M6618 PDU1 Evaluation Board Bill of Materials ................................................................... 22
Table 3: 78M6618 PDU-CT Evaluation Board Bill of Materials ................................................................ 32
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Teridian is a trademark of Maxim Integrated Products, Inc.
Windows and Windows XP are r egistered trademarks of M icrosoft Corp.
1 Introduction
The Teridian™ 78M6618 PDU1 evaluation board is an example of a low-cost power distribution unit
(PDU) utilizing the 78M6618 system-on-chip (SoC). The 78M6618 monitors the AC line voltage and eight
load currents, and controls switching of eight internal load relays. The embedded firmware calculates the
RMS line voltage and RMS load currents, watts, VAs, VARs, and power factor. The real-time data is
transmitted to a PC via a USB interface for display in a Windows
The 78M6618 UART interface is used as the communications link to an on-board isolated USB interface
IC.
®
-based graphical user interface (GUI).
Included with the 78M6618 PDU1 is a Windows-based GUI for simplified access to the following
measurement data and controls:
• RMS voltage and current
• Real, apparent, and reactive power and power factor
• Accumulated energy usage and expense tracking
• Line frequency
• Minimum and peak parameter tracking
• Alarm indicators
• Programmable alarm thresholds
• Internal load relay (16A) control
This document describes the evaluation board with “78M6618 PDU1_DIFF” imprinted on the board. This
board is a complete replacement for (and obsoletes) the earlier 78M6618 PDU1 evaluation board.
Refer to the GUI User Guide for information about the GUI.
1.1 Package Contents
The 78M6618 PDU1 evaluation kit includes:
• 78M6618 PDU1_DIFF evaluation board
• Universal AC to 12 V DC power supply with international plug adapters
• ICE Adaptor board
• USB A/B cable
1.2 System Requirements
The 78M6618 PDU1 GUI requires use of a PC with the following features:
• PC (1 GHz, 1 GB) with Microsoft Windows 7, Windows XP® or Win2000, equipped with USB port
• Minimum 1024 x 768 video display resolution
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1.3 Safety and ESD Notes
EXERCISE CAUTION WHEN LIVE AC VOLTAGES ARE PRESENT!
Standard ESD precautions must be taken when handling electronic equipment. The
78M6618 PDU1 contains ESD protected interfaces.
Do not connect test equipment, ICE emulators or external development boards directly to the
78M6618 hardware. Damage to the 78M6618 PDU1 and external equipment will occur due to the
78M6618’s “high side” reference topology. The 78M6618’s V3P3 (i.e., “high side”) is connected
directly to Neutral (Earth Ground) and the ground is 3.3V below neutral, creating a ground
reference disparity with any properly grounded external equipment. Also, reversing the line and
neutral connections at the inlet would place the board’s ground reference at the AC line voltage.
Always use the isolated USB interface for connecting to a PC. Contact the factory for instructions
on connecting other types of test equipment.
The board components and firmware settings are designed to operate with the following nominal AC
electrical ranges:
Voltage Current Line Frequency
110-240 VAC 20A Max 46-64 Hz
1.4 Firmware Demo Code Introduction
The Firmware Demo Code provides the following features:
• Basic energy measurement data such as Watts, Volts, current, VAR, VA, phase angle, power factor,
accumulated energy, frequency, date/time, and various alarm statuses.
• Control of alarm thresholds, calibration coefficients, temperature compensation, etc.
There are two means to facilitate performance evaluation between the user at the PC host and the
firmware code in the 78M6618 PDU1 evaluation board:
• The graphical user interface (GUI). For information about the GUI, refer to the GUI User Guide.
• The Command Line Interface (CLI) via HyperTerminal or comparable terminal emulator on a different
operating system. For information about the CLI, see the Firmware Description Document.
The 78M6618 PDU1 evaluation board is shipped with demonstration code loaded in the 78M6618 device
and included on the CD. The code revision can be verified by entering the command >i via the command
line interface. Firmware for the Demo Unit can be updated using either the Teridian TFP2 or an in-circuit
emulator such as Signum Systems ADM51 (
www.signum.com ).
1.5 Testing the Evaluation Board Prior to Shipping
Before every 78M6618 PDU1 evaluation board is shipped, the following procedures have been performed
at the factory:
• Full Calibration – Precise energy source equipment is used to calibrate the current and voltage. The
temperature is also calibrated at the same time.
• Accuracy Test – This “bench” level test ensures the energy measurement accuracy is within +/-0.5%.
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UM_6618_022 78M6618 PDU1 Evaluation Board User Manual
Outlet 2
Outlet 8
Outlet 7
DC Power Plug
(J48)
AC Inlet (J4)
Outlet 6
Outlet 4
Outlet 5
Outlet 3
Outlet 1
Connect the USB Port
(J47) to the Host PC
2 Installation
Figure 1 shows the basic connections to the 78M6618 PDU1 Evaluation Board. DC power is supplied to
the PDU1 through the DC power jack (J48). The USB cable provides an electrically isolated
communications link between the host PC and the PDU1 as well as power to the USB controller on the
Evaluation Board. The AC input to the PDU is connected via the terminal block J4. The PDU1 has eight
outlets that connect to the loads to be measured. Screw terminals are provided to make the line and
neutral connections to the loads.
Figure 1: 78M6618 PDU1 Connections
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2.1 USB Connection and Driver Installation
This evaluation kit includes an isolated USB interface for serial communications with a PC. The FTDI USB
controller IC FT232R performs the USB functions. The FTDI Windows driver presents a virtual COM port
for enabling serial communications. Control of the 78M6618-PDU-1 can be managed using either a
terminal emulation program or using the supplied Windows Dashboard GUI. The FTDI Windows driver is
a certified driver for Windows 2000 and XP.
Because the USB interface is USB powered, the USB driver installation can be completed with no other
DC power supplied to the evaluation board.
1. Connect a USB AB cable between the host PC and the evaluation board.
2. Upon attaching the 78M6618-PDU-1 to the PC, the Found New Hardware Wizard automatically
launches and installs the appropriate driver files. If your PC does not find the FTDI driver files on its
local hard disk drive, locate and reference the FTDI USB Driver and Utilities subdirectory on the CD.
The FT232R controller is powered from the USB cable and is active even when no AC power is
applied to the 78M6618-PDU-1.
Note: If an older FTDI driver has been previously installed, it is recommended to remove the older
version before installing this newer FTDI driver. Execute the ftdiClean.exe utility from the FTDI
USB Driver and Utilities subdirectory.
For FTDI driver support on other operating systems, please check FTDI’s website at
(http://www.ftdichip.com/FTDrivers.htm).
2.2 Connecting the External DC Supply
An external DC supply is provided for operation of the evaluation board. Follow these steps to connect
the 78M6618 PDU1 with the external DC supply:
1. Select the appropriate plug for the AC adapter and snap it into place.
2. Connect the DC cable of the 12V AC adapter to J48.
3. Plug the AC adapter into an appropriate outlet.
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PDU-1 COM Port:
2.3 Confirm COM Port Mapping
1. Launch the Control Panel and click on the System icon.
2. The System Properties screen appears. Click on the Hardware tab. Click on Device Manager.
Under Ports (COM & LPT), look for the USB Serial Port assignment.
3. Take note of the COM port assignment for the USB Serial Port.
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Select
COM Port
2.4 Verify Serial Connection to the PC
After connecting the USB cable from the 78M6618-PDU-1 to the host PC and powering the PDU board
with the 12VDC adapter, start the HyperTerminal application (or another suitable communication
program) to create a session using the communication parameters shown in Table 1. The firmware
installed in your board may use a different COM port setup than what is shown here. Refer to the
Firmware Description Document provided with your board for the correct setup for your firmware.
Table 1: COM Port Setup Parameters
Setup Parameter 78M6618
Port speed (baud) 38400
Data bits 8
Parity None
Stop bits 1
Flow control None
HyperTerminal can be found in Windows by selecting Start All Programs Accessories
Communications HyperTerminal. The connection parameters are configured by selecting File
Properties. The New Connection Properties menu appears.
Select the appropriate COM port and click Configure. The COMn Properties menu appears.
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UM_6618_022 78M6618 PDU1 Evaluation Board User Manual
Note that port parameters can only be adjusted when the connection is not active. It may be necessary to
click the Disconnect Button (shown below) to disconnect the port.
When the terminal emulation program has connected to the correct USB COM port, verify operation of the
PDU by pressing the “Enter” key on the PC. The evaluation board should respond with a “>” prompt. You
should also be able to identify the firmware version programmed into your board
If communication is not established with the evaluation board, check the following:
1. Make sure that 12VDC is supplied to the board through J48.
2. Make sure that the terminal emulation program is using the correct COM port.
3. Check the serial port configuration against the configuration given in the Firmware Description
Document.
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If the FTDI device driver did not install properly, there would be no assigned COM port
Disconnect
Figure 2: Serial Port Verification Screen
FTDI COM Port Trouble-Shooting
number for the FTDI controller. Repeat the USB Driver Installation, see Section 2.1.
Microsoft Windows may associate a Ball Point device to the FTDI USB controller. When this
occurs a FTDI device COM port assignment is available via HyperTerminal but there is no
communications data. Verify if a Ball Point device has been added to the “Human Interface
Devices” via the Device manager. Refer to Section 2.3 for access to the Device Manager. If
a Ball Point device exists, delete it and unplug and replug the evaluation board’s USB cable.
2.5 Connect the AC Source and Load
Connect the desired AC source to the terminal block J4. Be sure to observe the correct connections for
line and neutral as they are designated on the silk screen. Terminal block J4 accepts bare wires size
24AWG to 10AWG. Be sure to select wire gauge appropriate to the total load to be applied to the board,
and make sure that the screws are tightened for good electrical connection and wire retention.
The loads to be controlled and metered are connected to the screw terminals J7-J22 that are located on
the bottom edge of the board. These terminals can accept bare wire, or spade terminals or ring terminals
that are capable of accepting a 6-32 screw. The individual terminals are rated to carry a maximum current
of 15A. As with the AC inlet connection, be sure to observe proper connection to the AC line (labeled
Outlet n) and AC neutral.
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