BNC 725 User manual

Berkeley Nucleonics
Corporation
Model 725 Multi-Trigger Digital
Delay Generator
User Guide
Documentation for the Model 725
and timerPRO Software

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TABLE OF CONTENTS
INTRODUCTION 5
Parts List 5
Specifications 5
Basic Functions 6
How You Will Use the Model 725 6
Installing timer PRO Software 6
Setting Up the Model 725 7
Field Upgradeable Software 8
Getting Help 8
OVERVIEW OF MODEL 725 CONTROLS 9
Back Panel Inputs and Outputs 9
Front Panel Controls 10
SOFTWARE INTERFACE 11
Main Screen 11
General Settings 13
Disable/Enable I/O 13
Lock/Unlock Panel 14
Time base settings 14
CHANNEL PROPERTIES 15
Channel Properties Screen 15
Quiescent States 16
Logic 17
Logic Assignments 18
Parsing 19
Sending Logic 19

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Experimenting With Channel Logic 20
Rules for Logical Assignments 21
Predefined Variables 21
Global Variables 23
Timing Modes 25
“Apply” versus “Program All Channels” 26
Fixed Output Mode 27
Passive Mode (Output = Input) 28
Clocked Pulse Stream Mode 29
Delayed Pulse After Trigger Mode 31
Important Delay Timing Considerations 36
Validated Trigger Input Mode (Noise Suppression) 37
Timer Mode 40
Dynamically-Delayed Pulse Mode 42
Toggled Output Mode 47
Dynamic Delay Compensation Mode 47
RUNNING EXPERIMENTS 53
Storing and Recalling Experiment Files 53
Front Panel Controls and Indicators 53
Channel LEDs 53
ALL Channel LED 55
Selecting a Channel from the Front Panel 55
Performing a Front Panel Function 56
Enable/Disable ALL 56
Enable/Disable Channel 56
Trigger a Channel 57
Reset 57
Store/Recall Settings Profiles 57
GLOSSARY 59

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INTRODUCTION
The Model 725 is a fully programmable logic and timing controller for coordinating and
synchronizing lab equipment and physical experiments. Model 725 provides clocks, counters,
triggers, and many other useful functions, with 10 ns resolution and 100 ps accuracy.
The Model 725 consists of two components: timerPRO software and the Model 725 multi-trigger
digital delay generator. timerPRO lets you design and run experiments from a simple graphical
interface. The Model 725 provides the connections and control for your experimental devices.
Parts List
Your Model 725 package should include the following items:
1. The Model 725 multi-trigger digital delay generator
2. AC power cable
3. timerPRO software installation CD
4. 9-pin RS-232 cable
5. User’s manual.
If any parts are missing or damaged please contact technical support.
Specifications
timerPRO software will run on any computer running Microsoft® Windows®XP or later. Drivers
for National Instruments’® LabView™software are also available for download. See
www.berkeleynucleonics.com for more information.
The Model 725 includes eight TTL-compatible inputs and eight TTL-compatible outputs.
Voltages in the range 2.5–5 V are TTL “highs” and voltages in the range 0.0–0.2 V are TTL
“lows.” Intermediate voltages should not be present on inputs and outputs except during
transitions. The inputs and outputs are protected against connection to 115 VAC. When
disconnected the inputs are read as TTL “highs.”
The Model 725 can be connected to/ disconnected from the PC at any time without damage to
either unit. This ability allows you to program the Model 725 at your computer, then to take the
unit to the experiment area for stand-alone use.

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Basic Functions
The Model 725 provides eight functional channels, or internal signal paths.
At any time, each channel can be assigned one of eight timing modes. Timing modes include
clocks, counters, delayed pulses after triggers, etc. You can set various properties for each timing
mode—for example, the delay length on a Delayed Pulse After Trigger. All modes are aligned to a
precise, 100 MHz internal clock or an external clock, allowing resolution down to 10 ns.
Each channel also includes logic settings which specify the conditions that will trigger the
channel. A channel can be triggered by any logical combination of signals from the eight inputs
and/or the outputs of other channels.
The timing properties and logic that you set up in timerPRO can be transferred and stored in the
memory of the Model 725. You can store up to 64 variations of these properties in settings
profiles in the Model 725. You can then switch between settings profiles to switch experiments,
compare different timing scenarios, or simulate different real world conditions.
All settings and setting profiles for a particular experiment can be stored as an experiment file on
your computer. Experiment files bear a .trg extension.
How You Will Use the Model 725
In most cases, you’ll use the Model 725 as follows:
1. Using the timerPRO software, open an existing experiment file, or create a new file.
2. In timerPRO (or LabView), program the properties and logic for each channel and for the
experiment as a whole.
3. Send the properties and logic to the Model 725’s memory.
4. Test your program by simulating triggers and examining the outputs using the Model 725’s
channel LEDs and/or an oscilloscope or other diagnostic tool.
5. Store variations of channel properties in one of the Model 725’s 64 settings profiles.
6. Plug your experimental equipment to the Model 725.
7. Run the experiment, using the Model 725 by itself or leaving it tethered to the PC. Switch
between settings profiles to explore various timing conditions.
Installing timerPRO Software
Insert the timerPRO software disk in your computer drive and execute the setup.exe file.

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Setting Up the Model 725
1. Plug the power cable from the back of the Model 725 into a 100–250 VAC power outlet.
2. Connect the 9-pin cable to the back of the Model 725 and to a free serial port on the PC.
3. Press the Power button on the front of the Model 725.
4. From your computer, run timerpro.exe to launch timerPRO.
5. From within timerPRO, select View > Options>Com Port. The Serial Communications
Properties screen will open.
6. Select the port to which the Model 725 is connected. The Model 725 will automatically detect
the baud rate, which is typically set to 38400. If the RS-232 cable running to your Model 725
is greater than 30 m long, you may need to lower the baud rate to achieve reliable
communication.

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Field Upgradeable Software
The firmware in the Model 725 is field upgradeable, allowing access to new timing modes and
capabilities as they become available.
To upgrade the firmware, download the latest version from www.berkeleynucleonics.com. Then
choose Program > Update Firmware to load data from that file.
Getting Help
This guide is your main source for information on operating the Model 725 and timerPRO
software. The guide is also available in an Abobe®Acrobat®(pdf) file for electronic viewing.
While running timerPRO, press F1 to view this document online. Or, press SHIFT-F1, then
select a button or menu option to view help topics for a particular feature.
www.berkeleynucleonics.com also includes helpful applications notes and other technical
information to help you use the Model 725.
If you are unable to find the information you need, please contact our technical support team at +1
[phone], or e-mail us at [e-mail].
If you need to contact support, please let us know your Model 725 serial number (located on the
bottom of the unit) and the version of software you are using. To determine the software version,
select Help > About timerPRO.

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OVERVIEW OF MODEL 725 CONTROLS
The Model 725 is the control unit and interface for your experimental equipment. You will
program it using the timerPRO software. Once you’ve designed, tested and downloaded your
program, you can control the Model 725 from the computer, or you can run it in stand-alone
mode.
Indicators and controls on the Model 725 front panel will help you run your experiments. You’ll
learn all about these functions in the Experimenting section later. For now, we’ll give you a short
tour of the inputs, outputs and controls so you can work with the unit while you learn to use the
timerPRO software.
Back Panel Inputs and Outputs
The back panel includes the following connectors:
- an internally-fused jack for a standard 100–250 VAC power cord
- a 9-pin RS-232 jack to connect to the Com port of your PC
- eight BNC channel input jacks (in1–in8), normally high (5 V)
- eight BNC channel output jacks (outA–outH), normally low (0 V)
- a BNC input jack for an external clock source.
The inputs and outputs will accept any device into that sends or receives TTL-compatible signals.

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Front Panel Controls
The Model 725 front panel controls begin with the Power button and Power LED in the upper
left corner. When you first press the Power button, the LED will flash green and red while the
system runs its initial diagnostics. It will then glow steadily: if it glows a steady green, the front
panel is unlocked and accepting button pushes; if it glows red, the front panel is locked (see
timerPRO Software Interface: General Settings below). Even the power switch will be
deactivated, safeguarding against mis-setting or tampering.
The channel LEDs offer useful information about the state of each channel. A green light
typically indicates that the channel is ready to receive a trigger. A red light typically indicates that
the channel is in the process of triggering. When a channel indicator is off, the channel is disabled
(see Running Experiments: Enable/Disable Channels). More will be discussed in the Timing
modes section.
The All Channel LED shows the status for all channels. A green LED indicates that the Model
725 will respond to external inputs and that the external outputs are active. A red LED indicates
that the Model 725 will not respond to external inputs and that outputs are in a fixed and frozen
logical state.
The Channel and Function Buttons work as pairs—you will select one of each to perform any
function. In the base state, all buttons glow dimly, indicating that they’re ready for your
instruction. Once you press a channel or function button, only the available options will be
illuminated.
Power Switch Channel LEDs
Power LED Channel Buttons Function Buttons

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SOFTWARE INTERFACE
timerPRO has been designed exclusively for setup and control of the Model 725. You’ll use
timerPRO to set the timing properties and logic for each of the eight channels and to set up
overall properties for the experiment.
Main Screen
When you run timerPRO, you’ll be greeted by the Main screen:
NOTE: At start-up, the Main screen will show the default program, which sets
all channels to Delayed Pulse After Trigger mode.
From this screen you’ll control or access all of timerPRO’s functions. Most timerPRO functions
can be accessed in two ways by selecting an option from a pull-down menu or by pressing a
button on the Main screen.

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1. Menu options:
The File menu lets you open, close and save experiment files (.trg files).
The Edit Menu lets you cut, copy and paste text as you edit your program.
The View menu lets you set up the timerPRO interface. Choose to display or hide the
tool bars and status bar, select the font used in timerPRO, and set up communications
with the Model 725.
The Channel menu lets you open the screens for General Settings and for each of the
eight channels.
The Program menu includes options for communicating with the Model 725. You can
send logic, send properties, reset all channels, or enable/ disable the Model 725’s inputs
and outputs.
2. The buttons are as follows:
The General Settings button opens the General Settings screen.
The Channel buttons open the Settings screens for all channels.
The Program button updates the Model 725 with all current settings.
The Reset button resets all channels of the Model 725. Retriggering Counters and
delay settings will be reset as well.
The Main window panel shows a text summary of all of the settings in the current
experiment. This summary may be printed for review and documentation purposes. The
text is not freely editable and must be modified through the dialogs. Double-clicking on
selected parts of the summary opens the dialog needed to edit the text.
At any time, the Model 725 control bar can be hidden or displayed by clicking View > Model
725.

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General Settings
The General Settings screen lets you control functions that affect all channels of the Model 725.
To reach this screen, click the General Settings button, or choose Channel>General.
Disable/Enable I/O
On occasion you will need to abort an experiment or quickly place all outputs to your equipment
in a “safe” state. Each of the tabs of the General Settings screen includes buttons that let you
“disable” and “enable” all inputs and outputs to the Model 725. With I/O disabled, input signals
are ignored. Each output will be held at either a logic low or logic high, depending upon its
channel properties. We’ll refer to the “safe” voltage that a channel produces when disabled as the
“quiescent state” (see Channel Properties: Quiescent States). To restore channels functions, click
the Enable I/O button. These functions are nonvolatile: the enabled and disabled states are
restored on power cycle.
You can also disable or enable inputs and outputs from the Model 725 front panel (see
Experimenting: Disable/Enable All).

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Lock/Unlock Panel
Lock or unlock the front panel buttons using the Lock Panel and Unlock Panel buttons. This
functionality is handy, for example, in an embedded control application where the Model 725
should function only in stand-alone or computer-controlled modes. When the panel is locked, the
LED next to the power button glows a steady red and all buttons are dark. When the panel is
unlocked, the power LED glows green and the front-panel buttons are illuminated.
Like the enable/disable I/O functions, these settings are nonvolatile and are restored on power up.
Because the power button is disabled, the Model 725 must be disconnected from AC power to
turn it off, if the front panel is locked.
Time base settings
Each pair of channels of the Model 725 can independently utilize one of four different time bases
so you can control and measure events which occur a few nanoseconds apart, or a few hundred
seconds apart.
In 100 MHz time base mode (the default), the Model 725 aligns signals to an internal 100 MHz
clock, for timing resolution of 10 ns. Use this “high resolution” mode when the events of your
experiment occur in rapid succession (milliseconds or less).
100/64 MHz time base mode allows the Model 725 to control events that occur over longer time
periods (milliseconds to minutes). This is called “low resolution” mode in the following
documentation.
In Ext. time base mode, the channels use an external clock input for the time base. This input
must be TTL-level between 1 and 100 MHz applied to the External Clock (ext clk) input on the
back of the Model 725. This function allows the use of high-precision or variable-frequency time
bases. It also allows multiple Model 725s to be synchronized to the same base.
The External time base cannot be produced by a channel that uses the same time base as an input.
Ext./64 time base mode divides the frequency of the signal applied to the external clock input
before using it as a time base. If the external clock is being used as a time base, the frequency
entered into the edit box is used to calculate the timing settings. If this setting is 10% higher than
actual, the channels using this time base will be 10% long on delays and duration.
NOTE: When you change the time base setting a warning may appear listing
channels for which the clock range settings are invalid. The software will go into
“offline” mode allowing you to adjust the timing settings for the listed channels.
Once you’ve done so, go “online” and click Program > Program all channels.

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CHANNEL PROPERTIES
Channel Properties Screen
Each channel has a Settings screen in which you’ll select the timing mode, set the timing
properties, and establish the logic that will determine when the channel will trigger.
To open the Settings screen for a channel, select the channel from the Channel menu, or click a
channel button (A–H) on the Main screen. You can open more than one channel screen at a time.

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Channel properties are organized by tabs. The tabs that are relevant for a particular timing mode
appear automatically when that timing mode is selected. For convenience, all settings are retained
and saved, including those for timing modes that are not currently selected.
Four additional buttons appear next to the tabs:
-Disable temporarily disables the channel. The channel remains fixed in its “quiescent
state” (see Quiescent States below). The front panel LED for that channel will be unlit
(See Running Experiments: Channel LEDs).
-Enable restores channel functions following a temporary disable. The front panel LED
for that channel will glow to indicate the channel's status.
-Reset reinitializes the internal trigger counters and sweep timing for the current channel.
This function can be called simultaneously for all channels by pressing the Reset button
on the main tool bar.
-Force Trigger lets you simulate a valid input signal for the channel (see Channel
Properties: Logic for more). This button, which is only available with functions that can
be triggered, is useful both for troubleshooting your channel settings and implementing
software control of experiments. You can also force-trigger a channel from the Model
725 front panel (See Running Experiments: Force Trigger).
Quiescent States
When you disable a channel, its input will not change the output. The “quiescent state” of a
channel is the setting of its output when the channel is disabled. You can set each channel’s
quiescent state to be a TTL high (3.5–5 V) or low (0–0.2 V) to provide a safe signal to the output
device if you need to abort an experiment or stops its progress.
The method for setting the quiescent state depends on the timing mode. Most modes include an
Invert Output option which sets the output normally High.

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Logic
A channel can be triggered by any combination of signals from the eight inputs and/or other
channel outputs. Channel logic determines the combination of signals that triggers the channel.
The diagram below shows the architecture of the Model 725. Note that any inputs and outputs can
trigger a channel without external cabling.
To define when a channel will trigger, open the channel’s Settings screen then click the Logic tab.
This tab only appears for timing modes which respond to logic. You will enter a logic assignment
for the channel in the large white box.
NOTE: Some timing modes do not respond to trigger logic. For example, a channel
set to operate as a clock will continue to run regardless of what happens to its input.

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Logic Assignments
The logic processor assigns the combination of external inputs (in1–in8) and channel outputs
(outA–outG) that will trigger each channel. Logic assignments always appear in the following
format:
[the channel to be triggered] = [the conditions that will trigger it];
External inputs and channel outputs feed into the logic processors; therefore, they appear only on
the right side of assignments. Logic processor outputs feed the timing channel inputs inA–inH;
these terms appear only on the left side of assignments.
Here is an example:
inB = in2;
This assignment means, “Channel B will be TRUE when Input 2 goes TRUE (reaches ~ 5 V).”
The assignment:
inB = not in2;
means “Channel B will trigger when Input 2 goes FALSE (drops below 0.2 V).”
You can employ compound arguments in logical assignments, such as:
inB = not outC and in2;
This means, “Channel B will trigger when the output of Channel C is FALSE and Input 2 is
TRUE.”
This example is more complex still:
inB = (in1 or in2) and (outC or outD);
Here, Channel B requires a TRUE signal from Inputs 1 or 2, combined with a TRUE signal from
Channels C or D, in order to trigger.
NOTE: Model 725 inputs are TRUE by default if nothing is connected (i.e., the input is
normally weakly pulled high). Grounding an input switches its state to a logical FALSE.

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It is important to distinguish between the eight physical input jacks, in1–in8, and the eight timing
channel inputs. Any combination of the physical inputs can be used to trigger the channel inputs.
The following assignment is incorrect:
outA = in1;
because it attempts to trigger a channel output rather than a channel input, inA–inH
This assignment is also invalid:
in1 = in2;
because it attempts to assign a value to External Input 1.
Finally, this assignment is invalid:
inB = inA;
because it attempts to assign a value from one channel input to another.
Parsing
When you have completed a logical assignment, click the Apply button. timerPRO will check
your syntax and logic and will report any mistakes to you by line number.
Sending Logic
If you change channel logic you must transfer those changes to the Model 725 to implement them.
To transfer logic to the Model 725, click the Set All Channels button , or choose
Program >Program All Channels.
While the logic is transferring, the Power LED on the Model 725 will turn red. This transfer
typically takes only a second, though it may take slightly longer for complex programs.
After the transfer, the logic settings reside in the Model 725, even if you turn the unit off or
disconnect it from the PC.

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Experimenting With Channel Logic
This brief example will show you more about channel logic:
1. Connect a normally-open switch to Input 1 and another to Input 2.
2. Connect an LED to Output A.
3. Open the Channel Settings screen for Channel A.
4. Choose Output = Input from the Timing Mode list. In this mode, the output of Channel
A is always the same as its input.
5. Select the Passive tab and choose Output = Input.
6. Select the Logic tab and enter:
inA = in1;
7. Click the Set All Channels button.
The LED at Output A should be glowing, indicating that the output is TRUE, or HIGH (since
Model 725 inputs are normally HIGH). When you close Switch 1, the LED will turn off,
indicating that the output is FALSE, or LOW.
NOTE: The Channel A LED on the front of the Model 725 glows green while the
channel output is LOW, or red when the output is HIGH. The channel LED does not
always indicate the channel’s output state—only in certain Timing Modes. You’ll learn
more later in the Timing Modes section.
8. Next, change the logic assignment to:
inA = not in1;
9. Click the Set All Channels button. The LED at Output A will now remain off until you
close the switch.
10. Change the logic assignment to:
inA = not in2;
11. Click the Set All Channels button. The LED at Output A will now remain off until you
close Switch 2.