BNC 525 User manual

Operating Manual Version 1.0
Model 525
Pulse Generator
Berkeley Nucleonics Corporation
2955 Kerner Blvd.
San Rafael, CA 94901
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Web: www.berkeleynucleonics.com

Contents
PULSE GENERATOR ................................................................................................................................................................ 1
1INTRODUCTION .............................................................................................................................................................. 4
1.1 TECHNICAL SUPPORT.............................................................................................................................................................4
1.2 WARRANTY.........................................................................................................................................................................4
1.3 PACKAGE CONTENTS .............................................................................................................................................................4
2SAFETY ISSUES................................................................................................................................................................ 5
3CERTIFICATE OF CONFORMANCE.................................................................................................................................... 6
4FRONT & BACK PANEL OVERVIEW.................................................................................................................................. 7
4.1 FRONT PANEL......................................................................................................................................................................7
4.1.1 Indicators.................................................................................................................................................................7
4.1.2 Run/Stop/Power Button ..........................................................................................................................................7
4.2 BACK PANEL........................................................................................................................................................................7
4.2.1 Indicators.................................................................................................................................................................7
4.2.2 BNC Output Connectors...........................................................................................................................................8
4.2.3 USB ..........................................................................................................................................................................8
4.2.4 Run/Stop/Power Button ..........................................................................................................................................8
4.2.5 Gate/Trigger Input...................................................................................................................................................8
4.2.6 Clock In /Clock Out...................................................................................................................................................8
5PULSE CONCEPTS AND PULSE GENERATOR OPERATIONS ............................................................................................... 9
5.1 COUNTER ARCHITECTURE OVERVIEW .......................................................................................................................................9
5.2 SYSTEM TIMER FUNCTIONS ....................................................................................................................................................9
5.3 CHANNEL TIMER FUNCTIONS ..................................................................................................................................................9
5.4 DIGITAL OUTPUT MULTIPLEXER ............................................................................................................................................10
5.5 DEPENDENT &INDEPENDENT TIMING EVENTS (SYNC FUNCTION) ................................................................................................10
5.6 NAVIGATING THE 525.........................................................................................................................................................10
5.7 ENABLING SYSTEM OUTPUT .................................................................................................................................................10
6525 SETUP .....................................................................................................................................................................11
6.1 OVERVIEW ........................................................................................................................................................................11
6.2 POWER ............................................................................................................................................................................11
6.3 COMMUNICATION ..............................................................................................................................................................11
6.4 USB ................................................................................................................................................................................11
6.4.1 Driver Installation (Windows XP)...........................................................................................................................11
6.4.2 Driver Installation (Windows 7 and Greater) ........................................................................................................12
7525 APPLICATION ..........................................................................................................................................................13
7.1 525 APPLICATION OVERVIEW...............................................................................................................................................13
7.2 BASIC OPERATION ..............................................................................................................................................................14
7.2.1 System Section.......................................................................................................................................................14
7.2.2 Channels Section....................................................................................................................................................15
7.2.3 Options Section......................................................................................................................................................16
7.3 COMMAND TERMINAL.........................................................................................................................................................17
7.4 PARAMETER STORAGE.........................................................................................................................................................18
7.4.1 Saving Custom Settings to a Bin ............................................................................................................................18
7.4.2 Recalling Custom Settings from a Bin....................................................................................................................18
8OPERATING THE 525......................................................................................................................................................19
8.1 NORMAL INTERNAL RATE GENERATOR OPERATION...................................................................................................................19
8.1.1 Continuous Mode ..................................................................................................................................................19
8.1.2 Single Shot Mode...................................................................................................................................................20
8.1.3 System Burst Mode Function.................................................................................................................................20

8.1.4 System Duty Cycle Function...................................................................................................................................20
8.2 CHANNEL TIMER OVERVIEW .................................................................................................................................................20
8.2.1 Channel Normal Function ......................................................................................................................................21
8.2.2 Channel Single Shot Function ................................................................................................................................21
8.2.3 Channel Burst Mode ..............................................................................................................................................21
8.2.4 Channel Duty Cycle Mode......................................................................................................................................22
8.3 EXTERNAL INPUT OVERVIEW.................................................................................................................................................22
8.3.1 Generate a Pulse on Every Trigger Input ...............................................................................................................22
8.3.2 Using the External Gate to Control the System .....................................................................................................22
8.3.3 Using the External Gate to Control the Channel....................................................................................................23
8.3.4 Using the External Re-Arm ....................................................................................................................................23
8.4 OUTPUT EXAMPLES ............................................................................................................................................................24
9PROGRAMMING THE 525 ..............................................................................................................................................25
9.1 PERSONAL COMPUTER TO 525 COMMUNICATION ....................................................................................................................25
9.2 USB INTERFACE OVERVIEW..................................................................................................................................................25
9.3 PROGRAMMING COMMAND TYPES AND FORMAT .....................................................................................................................25
9.3.1 Line Termination....................................................................................................................................................26
9.3.2 IEEE 488.2 Common Command Format.................................................................................................................26
9.3.3 SCPI Command Keywords ......................................................................................................................................26
9.3.4 SCPI Command Format..........................................................................................................................................26
9.3.5 SCPI Keyword Separator ........................................................................................................................................27
9.3.6 SCPI Optional Keywords.........................................................................................................................................27
9.3.7 SCPI Parameter Types............................................................................................................................................27
9.3.8 Error Codes ............................................................................................................................................................27
9.3.9 Programming Examples ........................................................................................................................................28
9.4 525 SCPI COMMAND SUMMARY..........................................................................................................................................29
9.5 IEEE 488.2 COMMON COMMANDS ......................................................................................................................................33
10 APPENDIX A –SPECIFICATIONS..................................................................................................................................34
10.1 525 SPECIFICATIONS...........................................................................................................................................................34
11 APPENDIX D –TZ50 (IMPEDANCE MATCH OPTION) ...................................................................................................37
11.1 TZ50 OVERVIEW ...............................................................................................................................................................37
11.1.1 TZ50 Specifications ................................................................................................................................................37
11.1.2 Terminating Into 50 Ohms.....................................................................................................................................37
11.1.3 Terminating Into High Impedance.........................................................................................................................38
12 APPENDIX E –SAFETY SYMBOLS ................................................................................................................................39
12.1 SAFETY MARKING SYMBOLS .................................................................................................................................................39

1 Introduction
This manual is a reference designed to familiarize you with the BNC Model 525 Series Pulse Generator and is
arranged so that you can easily find the information you‟re looking for. Generally, each topic has its own section and
no section assumes that you‟ve read anything else in the manual.
Technical specifications including electrical ratings and weight are included within the manual. See the Table of
Contents to locate the specifications and other product information. The following classifications are standard
across all BNC Test and Measurement products.
Indoor use only
Ordinary Protection: This product is NOT protected against the harmful ingress of moisture.
Class 1 Equipment (grounded type)
Main supply voltage fluctuations are not to exceed +/-10% of the nominal supply voltage.
Pollution Degree II
Installation (overvoltage) Category II for transient overvoltage events
Maximum Relative Humidity: 0-80% RH, non-condensing
Operating temperature range of 0 oC to 40 oC
Storage and transportation temperature of -40 oC to 70 oC
Maximum altitude: 2000 m (6562 ft.)
This equipment is suitable for continuous operation.
Cleaning Instructions: Light dusting with cloth damp with water and/or usage of compressed air is all that is
needed.
1.1 Technical Support
For questions or comments about operating the Model 525 our technical staff can be reached via one of the
following methods:
• Phone - [phone]
• Fax - [phone]
• Email – [e-mail]
• Internet - www.berkeleynucleonics.com
1.2 Warranty
In addition to a 30-day money back guarantee, the model 525 has a two-year limited warranty from the date of
delivery. This warranty covers defects in materials and workmanship. If repairs are required during the warranty
period, contact the factory for component replacement or shipping instructions. Include the serial number of the
instrument. This warranty is void if the unit is repaired or altered by others than those authorized by Berkeley
Nucleonics Corporation.
1.3 Package Contents
The box you receive should contain the following:
•Model 525 Digital Delay / Pulse Generator
•USB Cord
•Disk that includes:
Operating Manual
Software Drivers
Application Software
Contact BNC [phone] if any parts are missing.

2 Safety Issues
Normal use of test equipment presents a certain amount of danger due to electrical shock because it may be
necessary for testing to be performed where voltage is exposed.
An electrical shock causing 10 milliamps of current to pass through the heart will stop most human
heartbeats. Voltage as low as 35 VDC or 35 VRMS AC should be considered dangerous and hazardous, as it
can produce a lethal current under certain conditions. Higher voltages pose an even greater threat because
such voltage can easily produce a lethal current. Your normal work habits should include all accepted
practices that will prevent contact with exposed high voltage and steer current away from your heart in case
of accidental contact with a high voltage. You will significantly reduce the risk factor if you know and observe
the following safety precautions:
If possible, familiarize yourself with the equipment being tested and the location of its high-voltage
points. However, remember that high voltage may appear at unexpected points in defective
equipment.
Do not expose high voltage needlessly. Remove housing and covers only when necessary. Turn off
equipment while making test connections in high- voltage circuits. Discharge high-voltage
capacitors after shutting down power.
When testing AC powered equipment, remember that AC line voltage is usually present on power
input circuits, such as the on-off switch, fuses, power transformer, etc.
Use an insulated floor material or a large, insulated floor mat to stand on, and an insulated work
surface on which to place equipment. Make certain such surfaces are not damp or wet.
Use the time-proven “one hand in the pocket” technique while handling an instrument probe. Be
particularly careful to avoid contact with metal objects that could provide a good ground return path.
Never work alone. Someone should always be nearby to render aid if necessary. Training in
CPR first aid is highly recommended.

3 Certificate of Conformance

4 Front & Back Panel Overview
4.1 Front Panel
4.1.1 Indicators
A total of up to 9 separate LED indicators are included on the front panel of the 525. The following details the
type of indication they represent.
Power
Indicates the unit is powered on.
Channel A-F
Indicates which channels are in the enabled state.
Active
Ext In
Indicates the unit is armed and/or channels are actively
pulsing (or waiting to be triggered).
Indicates external mode is either set to gate or trigger.
4.1.2 Run/Stop/Power Button
The Run/Stop button serves the dual purpose of both powering on/off the unit as well as enabling/disabling the
system output. It should be noted that only a short press is needed to both turn on and arm/disarm the unit.
The button needs to be pressed and held for approximately 1 second in order to power off the unit. In the
power off sequence the active settings are saved and reloaded when the unit is power back on.
The following image represents the front panel of a 525.
Figure 3.1 - 525 Front Panel
4.2 Back Panel
4.2.1 Indicators
A total of up to 10 separate LED indicators are included on the back panel of the 525.The following further
details the type of indication they represent.
PWR
Indicates the unit is powered on.
Channel A-F
Indicates which channels are in the enabled state.

Active
Indicates the armed channels are actively pulsing (or waiting
to be triggered).
Gate/Trig
Indicates which mode the external input is in. If neither is
illuminated, the unit is in internally triggered mode.
4.2.2 BNC Output Connectors
Standard BNC connectors are found on the back panel which output the pulses for their respective channel.
4.2.3 USB
A “Standard B” female type USB connector is found on the back panel. This provides power to the unit as well
as communication (on standard units).
4.2.4 Run/Stop/Power Button
The Run/Stop button serves the dual purpose of both powering on/off the unit as well as enabling/disabling the
system output. It should be noted that only a short press is needed to both turn on and arm/disarm the unit.
The button needs to be pressed and held for approximately 1 second in order to power off the unit. In the
power off sequence the active settings are saved and reloaded when the unit is power back on.
4.2.5 Gate/Trigger Input
The Gate/Trig input allows external signals to either trigger or gate output events depending on setup.
4.2.6 Clock In /Clock Out
The Clock In allows external synchronization with other instruments. Various clock frequencies can be applied to the
input when the unit is set to external clock mode. The Clock Out will output various frequencies as well as a T0
signal. These outputs are user selectable.
The following image represents the back panel of a 525.
Figure 3.2- 525 Back Panel

5 Pulse Concepts and Pulse Generator Operations
5.1 Counter Architecture Overview
*Start source is:
Run/Stop button/function in Internal Modes
External input in External Trigger modes
*TRG command via Serial access
**Channels are armed by the Run/Stop function (external button or through 525 application). In
single shot and burst modes channels may be rearmed by pressing the RUN button again.
5.2 System Timer Functions
The System Timer functions as a non-retriggerable, multi-vibrator pulse generator. This means that once
started, depending on the mode, the timer will produce pulses continuously. Before pulses can be generated,
the timer must be armed and then receive a start pulse. Arming the counter is done by enabling the Run/Stop
function by either the external button or through the 525 application. With external trigger disabled, the
Run/Stop function also generates the start command for the counter. With external trigger enabled, the
external trigger provides the start pulse. In either case, once started, the counter operation is determined by
the System Mode Generator. Standard modes include:
Continuous
Once started T0 pulses are generated continuously.
Single Shot
One T0 pulse is generated for each start command.
Burst
„N‟ T0 pulses are generated for each start command.
Duty Cycle
Once started T0 pulses cycle on and off continuously.
The T0pulse is distributed to all of the start inputs of the Channel Timers and Mode Generators.
5.3 Channel Timer Functions
The Channel Timer functions as a non-retriggerable, delayed, one shot pulse generator. This means that the
timer will only generate one delayed pulse for every start pulse received. Once the channel timer has started
counting, additional start pulses will be ignored until the pulse has been completed (non-retriggerable). The
start pulse for each channel is provided by the internal T0pulse generated by the internal system timer.
Whether or not a pulse is generated for each T0pulse is determined by the Channel Mode Generator.

Standard modes include:
Normal
A pulse is generated for each T0pulse.
Single Shot
One pulse is generated for the first T0pulse, after which
the output is inhibited.
Burst
„N‟ number of pulses are generated for each T0pulse, after
which the output is inhibited.
Duty Cycle
„N‟ number of pulses are produced, one for each T0pulse,
after which „M‟ number of pulses will be inhibited, one for
each T0pulse. The cycle is then repeated for each
subsequent T0pulse.
A Different mode may be selected for each channel, allowing a wide variety of output combinations. Each
output may also be independently disabled or gated (using the external gate input).
5.4 Digital Output Multiplexer
The outputs of each of the Channel Timers are routed to a set of multiplexers. This allows routing of any or all
Channel Timers to any or all of the units‟ outputs. In the normal mode of operation, the output of the n th Channel
Timer is routed to the nth output connector. As an example, if a double pulse is required on Channel A, one can
multiplex the Channel A timer with the Channel B timer, then adjust each timer to provide the necessary pulses.
Only the timing parameters are multiplexed together, not the actual output amplitudes.
5.5 Dependent & Independent Timing Events (Sync Function)
The 525 allows the user to control the relationship between the Channel Timers by setting the sync source for
each timer. Independent events are all timed relative to the internal T0start pulse. Dependent events may be
linked together by setting the sync source to the controlling event. This allows the instrument to match the timed
events and adjustments can be made in one event without detuning the timing between it and the dependent
event.
5.6 Navigating the 525
Primary control of the 525 is carried out either through the 525 application (see 525 application Menus) or
through unit specific commands using a terminal program via USB (see Programming the 525). The Run/Stop
buttons found on either side of the 525 serve the purpose of both power on/off as well as enabling/disabling the
system output.
5.7 Enabling System Output
The Run/Stop button found on both the front and back panel of the 525 is used to arm the system. With
external trigger disabled, the button will arm and start pulse output. With external trigger enabled, the button
will arm the pulse generator. Pulse outputs then starts after the first valid trigger input. Pressing the Run/Stop
button a second time disables the pulse generator.

6 525 Setup
6.1 Overview
The 525 can easily be interfaced by means of the included 525 application. On standard models, a USB cable
and a port with USB 2.0 capabilities or greater (recommended) are required to communicate with the unit. If the
equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may
be impaired.
6.2 Power
The 525 requires a +5VDC±250mV (≤470mA) power supply to operate. When the power is supplied from a
computer device, it is recommended that a USB 2.0 port (or greater) is used. The unit may also be powered
directly from a 5VDC USB DC wall-mount supply (≥470mA). The current draw is highly dependent on the
external loads. If all loads are high impedance, the unit will require far less current to operate correctly. It
should be noted that if 525 consumes ≥500mA, the internal current sense circuit will cause the unit to go into a
latched state, which will be indicated by error beeps. In this state, all outputs will be inactive. In order to clear
this state, the 525 must be power cycled. In order to further avoid this state, it is highly recommended that loads
connected to any of the outputs be ≥50 ohms. The USB cable should be plugged into the rear panel of the unit
that is labeled USB. The multi-functional power button, labeled “Run/Stop,” located on both front and back of
the unit will turn on the 525 when pressed once. If a USB DC wall-mount supply is chosen to be used, it is
recommended that the AC Mains Socket-Outlet be easily accessible so that the external power supply can be
easily removed from the AC Mains Socket Outlet.
6.3 Communication
The 525 provides a standard USB connection for remote communications.
6.4 USB
When the 525 is connected to a remote computer via the USB connection, the computer will recognize the unit
as a USB to Serial Port Adapter. Normally the Windows operating system will automatically install drivers for the
525, but in the event it does not and drivers need to be installed, the following steps can be followed depending
on the version of the operating system. Drivers are included on the provided CD. Once the drivers have been
installed, the 525 will show up in the device manager as a USB to Serial Port Adapter. The 525 can then be
communicated with by either the included 525 application or by using any generic communication terminal
program. The unit is baud rate independent, so any speed can be selected. Typically a rate of 115,200bps can
be used.
6.4.1 Driver Installation (Windows XP)
1. Plug the 525 into the computer using a USB cable. Make sure the unit is powered on.
2. The computer will display a message indicating it has found new hardware: “BNC-PG”.
3. The new hardware wizard will launch. Check the “Install from a list or specific location” option and click
next.
4. Select “Search for the best driver in these locations” and check the option to “Include this location in the
search”. Click the browse button and locate the folder on the CD where the 525 drivers are located.
Click next.
5. A message window will launch asking if you want to continue installing this driver. Select the “Continue
Anyway” button.
6. It should now indicate that it is installing a driver for a “BNC-PG USB Communications Port”.
7. Once the process is finished, a message will indicate that the drivers have been successfully installed.
8. You can now communicate with the 525 using either the included 525 application or by using any generic
communication terminal program. You can view the Com Port number assigned to the 525 in your
computers device manager under Ports.

6.4.2 Driver Installation (Windows 7 and Greater)
1. Plug the 525 into the computer using a USB cable. Make sure the unit is powered on.
2. A message will pop up on the computer indicating it has found new hardware and is installing device
driver software.
3. A message will indicate that the device drivers have not been successfully installed. The Action Center
may then launch with a list of options. Close the Action Center and do not launch any of the actions.
4. Go to your computers device manager. This can be done by one of two ways. a) Right click on the
desktop “Computer” icon and select properties. Select Device Manager on the left toolbar. b) Navigate
to Control Panel and then Device Manager.
5. In Device Manager you should see a device under the Other Devices called the BNC-PG. There will be a
yellow exclamation point next to it.
6. Right click on the BNC-PG and select update driver software.
7. Select “Browse My Computer” for driver software and browse to the location of the USB drivers for the
525. The location is typically found on the software CD. It will contain a file called “525cdc.inf”. Select
the folder in which the file resides, not the file itself. Click next.
8. Windows will then indicate a warning window that the drivers are not verified. Select “Install this driver
software anyway”.
9. A message will then indicate that the drivers have been successfully updated and a BNC525 USB
Communication Port is now available.
10. You can now communicate with the 525 using either the included 525 application or by using any generic
communication terminal program. You can view the Com Port number assigned to the 525 in your
computers device manager under Ports.

7 525 Application
7.1 525 Application Overview
Aside from using the SCPI command protocol, the included software application is the primary means of
communication with the 525. This application allows simple control of the 525 unit via the USB communications
port. To run the software, simply double click on the application which can be found on the included CD. No
installation is required. The software can also be copied to your computer and run from any location. The
screenshot shown on the following figure shows the 525 application and all of the corresponding default
parameters:
Figure 7-1 - 525 Application Shown In Default State

7.2 Basic Operation
The following steps must be carried out before communication with the 525 may take place:
Ensure that the proper drivers have already been installed on the remote computer. These drivers will
need to be installed for the remote computer to interface to the 525. Reference the “525 Setup USB”
section for more information on installing the proper drivers.
Open the 525 application by double clicking on the application which can be found on the included CD.
Once the 525 application recognizes the COM Port the 525 is attached to, a connection will be
established, and communication may now be carried out.
7.2.1 System Section
The System Section of the 525 application only affects the 525‟s system parameters. As shown below, the
following system parameters may be altered:
Figure 7-2 –525 Application: System Parameters
Pulse Mode: Changes the system‟s output mode to Continuous, Single Shot, Burst, or Duty Cycle.
Period: Sets the System‟s T0period. Valid inputs are 200ns–1000s set in 10ns increments.
System Resolution: Changes the system resolution between 4ns and 5ns. This affects the period,
widths and delays. This will also affect some of the system performance specifications.

Duty Cycle: If Duty Cycle has been selected in the System‟s Pulse Mode, the unit will generate a
continuous pulse stream in which outputs will be On for “N” pulses and Off for “M” pulses. One may
alters the “N” (On) and “M” (Off) parameters:
On Counts (“N”): Positive integer value which designates the number of pulses to
produce during the “On Cycle.” Valid inputs are 1 -1,000,000.
Off Counts (“M”): Positive integer value which designates the number of pulses to
suppress during the “Off Cycle.” Valid inputs are 1-1,000,000.
Burst Count: If Burst mode has been selected in the System‟s Pulse Mode, the Burst Counts positive
integer input selects the number of T0pulses generated once the Run/Stop button has been pressed.
Valid inputs are 1-1,000,000.
Run: Enables or disables the output for all channels. This command is the same as pressing the
Run/Stop button on either the front or back panel.
Auto Start: Enables or disables the Auto Start function. If enabled, the unit will start pulsing
immediately upon power-up or be in an armed state if in external mode.
External Trigger/Gate: Selects the system‟s External Mode to be Disabled, Triggered, Gated , or
ReArm. If either Triggered, Gated or ReArm is selected, the following sub-parameters may be set.
oThreshold (V): Sets the trigger threshold Voltage in 10mV increments. Typically this value
should be set to 50% of the incoming trigger voltage for optimum trigger response. Valid
threshold values are 0.20V-15V. The unit can handle up to a 30V external input.
oPolarity: If the External Mode has been set to Gated, alter the Polarity to the required polarity.
Active low or active high are the available modes.
oTrigger Edge: If the External Mode has been set to Triggered, alter the Trigger Edge to the
required transition. Rising or falling edge are the available modes.
7.2.2 Channels Section
The Channels Section of the 525 application only affects the 525‟s channel parameters. Complex pulse trains
can be created by combining various system and channel modes. As shown below, the following channel
parameters may be altered:
Figure 7-3 –525 Application: Channel Parameters
Channel Selection: Select the proper Channel tab in order to further edit the parameters on the
corresponding channel.
Enabled: Enables and Disables the output for the selected channel.

Delay: Sets the delay from the timing reference to when the pulse is created. Valid input is ±1000s with
10ns increments. Note: negative delays are only applicable if you are referenced to a channel that has a
positive delay.
Width: Sets the pulse width for the selected channel. Valid input is 10ns –1000s with 10ns increments.
Amplitude: Allows the user to select the voltage amplitude of the output. Valid values are 3.3V –5V
with 20mV increments.
Channel Mode: Changes the Channel Mode to Normal, Single Shot, Burst, or Duty Cycle.
oNormal: Channel will produce pulses as long as a T0is present (mimics System Pulse Mode)
oDuty Cycle: If Duty Cycle has been selected in the Channels section, the unit will generate a
continuous pulse stream in which outputs will be On for “N” pulses and Off for “M” pulses. One
may alters the “N” (On) and “M” (Off) parameters:
On Counts (“N”): Positive integer value which designates the number of pulses to
produce during the “On Cycle.” Valid inputs are 1-1,000,000.
Off Counts (“M”): Positive integer value which designates the number of pulses to
suppress during the “Off Cycle.” Valid inputs are 1-1,000,000.
oBurst Counts: Selects the number of pulses to output with each input clock pulse. Valid input
is 1-1,000,000.
oSingle Shot: Will produce one pulse each time the channel is armed.
Sync Source: Selects the timing reference for the selected channel. Each channel may be set to sync
to T0or may be set to sync to a different channel. It should be noted that if a channel is set to sync to a
separate channel a negative delay may be used as long as that delay does not require the pulse be
produced before the T0pulse is produced. For example: the value of (T0+ Sync source delay + channel
delay) must be greater than or equal to 0.
Wait Counts: Selects how many T0pulses to wait until the channel outputs its first pulse. Valid input is
0-1,000,000.
Polarity: Selects the Channel‟s Polarity. Normal is active HIGH, Inverted is active LOW.
Mux: The outputs of each of the Channel Timers are routed to a set of multiplexers. This allows routing
of any or all Channel Timers to any or all of the units‟ outputs. In th e normal mode of operation, the
output of the nth Channel Timer is routed to the nth output connector. As an example, if a double pulse is
required on Channel A, one can multiplex the Channel A timer with the Channel B timer, then adjust
each timer to provide the necessary pulses. Only the timing parameters are multiplexed together, not the
actual output amplitudes.
Gate Mode: Selection determines which active state will gate the selected channel output.
7.2.3 Options Section
The Options Section of the 525 application has additional advanced features. The following figure shows the
additional options:

Figure 7-4 –525 Application: Options Section
Shot Counter: The “Shot Counter” can be set up to count the system (To) or any of the available
channel outputs. This counter is a 32 bit counter that can be enabled and reset by the user by means of
the “Enable” selection and “Clear” button.
Period Counter: The “Period Counter” measures the period of the incoming external trigger pulses. The
period counter must be first enabled by means of the “Enable” selection. This counter can average up to
15 periods for greater accuracy. This is controlled under the “Periods to Average.” If the period coun ter
is selected to run in manual mode (“Auto Update” not enabled), it will latch the incoming period
measurement and hold the reading. If “Auto update” mode is selected, the reading will constantly be
updated as long as external triggers are applied. The displayed measurement may be cleared at any
time by means of the “Clear” button. To use this option, the system must be in external trigger mode.
Sync Update: The ”Sync Update” allows for the channel timers (delays and widths) to be manually
updated so that all changed values are applied synchronously. Normally when any width or delay is
changed, it is automatically applied. When Synchronous Update Mode is selected to be enabled, all
channel width and delays can be adjusted and then updated simultaneously via the “Update” button (or
SCPI command).
Duty Cycle Counts: This parameter will determine the number of cycles the duty cycle sequence will
execute. Normally, the duty cycle continues until stopped by the user; although, now a specified number
of duty cycle events can be executed. If set to 0, the cycles will continue until stopped by the user. This
feature can be thought of as a “burst” mode for duty cycle.
Clock Input: This allows the unit to be synchronized with another device. When an external clock
source is applied to this input and the proper frequency is selected, the 525 will lock onto the input
source derive its internal clock from the external source.
Clock Output: The clock output can be set to output various frequencies including the T0 reference
signal. The other output frequencies can be utilized to synchronize another external device with the 525.
7.3 Command Terminal
The Command Terminal Section on the 525 application shown below allows the user to manually input SCPI
based commands in order to alter parameters on the 525. See “Programming the 525” for more information on
sending and formatting commands. It should also be noted that whenever a selection is made on the 525
application, the corresponding SCPI based command will automatically be sent through the Command Terminal
to the device.

Figure 7-5 –525 Application: Command Terminal
7.4 Parameter Storage
7.4.1 Saving Custom Settings to a Bin
The 525 series has the capability to save up to 6 custom user setups. Once all the custom user settings are
ready to be saved to one of six bins, click “Storage”, “Save To Bin”, followed by selecting the bin number to save
the custom settings to. The following figure represents the saving process:
Figure 7-6 –525 Application: Saving To Bin
7.4.2 Recalling Custom Settings from a Bin
The 525 series has the capability to recall any of the 6 custom user setups. If any of the previously saved
presets are to be recalled, click “Storage”, “Restore From Bin”, followed by selecting the bin number to recall.
The following figure represents the recalling process:
*Note: Selecting Default 0 will set the 525 to factory default settings.
Figure 7-7 –525 Application: Recalling From Bin

8 Operating the 525
8.1 Normal Internal Rate Generator Operation
The 525 has a complete set of functions providing a number of modes of operation for the internal or “System”
rate generator (T0). Most of these functions can be ignored if a simple continuous stream of pluses is required.
Starting from the default settings, which can be restored by recalling configuration 0, the following parameters
need to be set in the 525 application:
Pulse Width, Delay
Enter the required pulse width and delay found in the Channel
section. Repeat for each output channel.
T0Period
Set the desired pulse Period found in the System section.
Enable
*Note: In general the pulse delay + the pulse width + 75 ns (for a
hardware reset for any channel) must be less than the T0
period.
Enable the corresponding channels by clicking “Enabled” in the
Channel section.
Start
Press the unit‟s Run/Stop button to start generating pulses
Stop
Press the unit‟s Run/Stop button once again to stop generating
pulses.
8.1.1 Continuous Mode
Pressing the unit‟s Run/Stop button starts and stops a continuous pulse stream at the rate specified by the
Period parameter. This corresponds to the default output mode for most pulse generators. To generate a
continuous stream of pulses, set the following parameters in the 525 application:
Within the System section:
oSelect Continuous mode.
oSet the desired pulse Period.
Within the Channel section:
oEnter the required pulse width and delay. Repeat for each output channel.
oEnable the corresponding channels by clicking “Enabled” in the 525 application.
Pressing the unit‟s Run/Stop button will now generate a stream of T0pulses at a rate specified by the Period
parameter.

8.1.2 Single Shot Mode
Pressing the unit‟s Run/Stop button generates a single pulse with every press. Set the following parameters in
the 525 application:
Within the System section:
oSelect Single Shot mode.
Within the Channel section:
oSet channel mode to Normal.
oEnter the required pulse width and delay. Repeat for each output channel.
oEnable the corresponding channels by clicking “Enabled” in the 525 application.
Pressing the unit‟s Run/Stop button will now generate one pulse out of every enabled channel.
8.1.3 System Burst Mode Function
The Run/Stop button generates a stream of „N‟ T0pulses, where the „N‟ is specified by the Burst parameter. The
rate is specified by the Period parameter. Pressing the Run/Stop button while the burst is in process will stop the
output. After the burst has been completed, pressing the Run/Stop button will generate another burst of pulses.
To generate a burst of pulses set the following parameters in the 525 application:
Within the System section:
oSelect mode to be Burst.
oSet the Burst Count parameter field to produce the number of pulses desired
oSet the desired Period.
Within the Channel section:
oSet channel mode to Normal.
oEnter the required pulse width and delay. Repeat for each output channel.
oEnable the corresponding channels by clicking “Enabled” in the 525 application.
Pressing the unit‟s Run/Stop button will now generate the predefined burst of pulses out of every enabled
channel.
8.1.4 System Duty Cycle Function
The Run/Stop button starts a continuous stream of T0pulses, which repeats for „N‟ pulses On and „M‟ pulses Off,
where „N‟ and „M‟ are specified by the On/Off parameters respectively. The rate at which the pulses are
generated is controlled by the Period parameter. To generate a stream of pulses which will repeat for „N‟ pulses
On and „M‟ pulses, set the following parameters in the 525 application:
Within the System section:
oSet the mode to Duty Cycle.
oSet the On parameter to the number of pulses to produce during the on cycle („N‟).
oSet the Off parameter to the number of pulses to suppress during the off cycle („M‟).
oSet the desired Period.
Within the Channel section:
oSet channel mode to Normal.
oSet the Sync Source to T0 in each respective channel tab.
oEnter the required pulse width and delay. Repeat for each output channel.
oEnable the corresponding channels by clicking “Enabled” in the 525 application.
Pressing the unit‟s Run/Stop button will now generate duty cycle pulses out of every enabled channel.
8.2 Channel Timer Overview
The output of each channel is controlled by two timers to generate the pulse width and the delay timing. All