Mi-Wave 511 User Manual

User Guide

511 Series Programmable Attenuator

VERSION 2

2

Table of Contents

Specications . . . . . . . . . . . . . . . . . . . . . 

Initial Setup . . . . . . . . . . . . . . . . . . . . . . 

Local Mode Operation . . . . . . . . . . . . . . . . 

Front and Back Panel View. . . . . . . . . . . . . . 

Implementing Custom GPIB Connection . . . . . . 

Implementing Custom USB Connection . . . . . . 

Index. . . . . . . . . . . . . . . . . . . . . . . . . . 

3

Specications

Supply Voltage

Attenuator Speed 35 dB/s

Max Attenuation 70 dB

Resolution 0.01 dB

USB Port Type 2.0

GPIB Protocol National Instruments 488.2

+24V

4

Initial Setup

NOTE: Initial Setup can be accessed by pressing MENU from the Front Panel, only when the unit is not in operation.

Refer to Figure 1 and Figure 2 below for Front Panel View and Back Panel View respectively.

• Power: Connect the Power Adapter on the Back Panel to DC Input and Turn ON the Power Switch.

• Remote Mode: To enter Remote Mode, press MENU followed by 1.0 on the Front Panel. Then press
MENU a second time to exit.

• Local Mode: The unit can switch back to Local Mode by pressing MENU followed by 10 and a second
MENU press to exit.

• Product Information: To view Serial Number, Manufacturing Date and Frequency Band, press 0.1. After
this the clock must be set to the correct date/time by pressing 10 and 1.0 until the correct values are
listed. Press ENTER to save.

• GPIB Address: To set the GPIB address, press .01 to select the desired address in range 1–30 and then
press MENU to store the address and exit. Once the address is set and stored, ON/OFF Power cycling will
not change the address.

Local Mode Operation

• Local Mode: The unit can switch to Local Mode by pressing MENU followed by 10 and a second MENU
press to exit.

• Upon entering Local Mode, the unit will automatically set the attenuation to 70 dB. To select a new
attenuation level, rst press 10 to change the displayed value to 0.00 dB. Each time 10 is pressed, the
attenuation will increase by 10 dB until 70 dB is reached, at which point the attenuation will start back
at 0.00 dB with another button press. Pressing 1.0 will increase the displayed value by 1 dB, and so
forth for the 0.1 and .01 buttons.

• After the desired attenuation value is displayed, press ENTER to set it.

5

Front and Back Panel View

Figure 1: Front Panel View

ON

OFF

Figure 2: Back Panel View

6

Implementing Custom GPIB Connection

Initial Software Installation and requirements:

• Microsoft .NET Framework 4.5 or above

• National Instruments 488.2 GPIB Driver with support for .NET Framework option

Congure GPIB Settings

This can be done through the Interactive GPIB Utility installed with the National Instruments Driver or via
custom code.

1. Initiate GPIB Connection via the National Instruments command “ibdev”. Refer to Figure 3 below.

2. Enter board index of GPIB Adapter that the device is connected to. If the board index is unknown,
open National Instrument’s Measurement & Automation Explorer (NI MAX), click the “DEVICES AND
INTERFACE” tab. Device will be listed as “NI GPIB-USB-HS GPIBx ” where “x” is the board index

3. Enter the primary GPIB address of the unit. To change the primary GPIB address, refer to section 1.5

4. Secondary address is never used and must always be set to 0.

5. For timeout, enter 13

6. Enter 1 for ‘EOI on last byte’ ag

7. Enter 0 for end-of-string mode/byte

8. The unit will then exit the screen stating “Initiate GPIB or USB connection,” (This is based o of the GPIB REN
line being asserted upon calling “ibdev”).

Figure 3: Screenshot of command “ibdev” initiated with National Instruments GPIB Interactive Control utility

Figure 4: Screenshot of command “ibwrt” to set attenuation to 5.5 dB

immediately after the above call to “ibdev”

7

Set desired frequency attenuation levels via the command “ibwrt”.

The input for “ibwrt” must be a string ranging from 0 to 70 terminated by the newline characters
“\r\n”(CRLF). An example implementation of “ibwrt” is shown on previous page 7 in Figure 4.

Read a response string from GPIB command via “ibrd”.

If a response from each GPIB command is desired, call “ibrd” immediately after sending an “ibwrt” command.
Sending “ibrd” with a byte count equal to the incoming buer size will return the string “GPIB CMD: xx
dB complete.\r\n”. It should be noted that only custom software can send “ibrd” in time to catch the
response (typing “ibrd” manually in the Interactive GPIB Utility after an “ibwrt” is too slow).

Figure 5: Screenshot of command “ibrd” to read response from GPIB

ATTEN TION:

Close GPIB connection via command “ibonl”, followed by the respective GPIB board index when
finished.

NOTE: The command “ibonl” ends the GPIB connection and cleans up memory resources for all devices

connected to the respective board index entered in the command. This should be called before closing any
custom GPIB communication programs with the device. A demonstration is shown below in Figure 6 for board index 0.

Figure 6: Screenshot of command “ibonl” for board index 0

Warning

Never leave unconnected GPIB cables attached to the device during use; this can

distort sent commands and incoming responses.

Always call “ibonl” or unplug the GPIB cable before powering the device o.
Failing to do so will result in an incomplete device reset. See above "Attention"
section for more information on “ibonl”.

8

Implementing Custom USB Connection

Initial Software Installation:

• Download and Install VCP (Virtual COM Port) driver from FTDI website:

• http://www.ftdichip.com/Drivers/VCP.html

Congure Serial Port Settings

• Locate device COM port number. In Windows “Device Manager,” the device can be found under

“Ports.” It will be listed as “USB Serial Port,” with its respective COM port number located next to it.

• Baud rate should be set to 57600.

• 8 data bits

• No Parity

• 1 stop bit

• No Flow Control

Any method of creating a serial port connection with these settings will suce. One simple solution is
to use the C# .NET “SerialPort,” class to create custom USB communication software for the device.

Send attenuation commands ranging from 0 to 70 terminated via

“\r\n”(CRLF)

If each command is not terminated by \r\n the serial buer on the device will continue to ll up with
commands but none will be processed.

A response to each USB command

Once the motor has completed its motion, “USB CMD: xx dB complete.\r\n” will be sent
across USB from the device. Read the incoming serial buer as a string to receive this message.

9

Index

B

Back Panel, 6

C

Clock, 5

F

Frequency Band, 5

Front Panel, 6

G

GPIB, 7, 8

I

ibdev, 7, 8

ibonl, 8

ibrd, 8

ibwrt, 8

L

Local Mode, 5

M

Manufacturing Date, 5

N

NI MAX, 7

R

Remote Mode, 5

S

Serial Number, 5

Serial Port, 9

U

USB, 9

V

Virtual COM Port (VCP), 9

10

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Millimeter Wave Products, Inc.
2007 Gandy Blvd, Suite 1310
Saint Petersburg, FL 33702

www.miwv.com

Phone: [phone]
Fax: [phone]
Email: [e-mail]