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BNC 725 User Manual

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

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  • Page 1 Berkeley Nucleonics Corporation Model 725 Multi-Trigger Digital Delay Generator User Guide Documentation for the Model 725 and timerPRO Software...

  • Page 3: Table Of Contents

    TABLE OF CONTENTS INTRODUCTION Parts List Specifications Basic Functions How You Will Use the Model 725 Installing timer Software Setting Up the Model 725 Field Upgradeable Software Getting Help OVERVIEW OF MODEL 725 CONTROLS Back Panel Inputs and Outputs Front Panel Controls...
  • Page 4 Experimenting With Channel Logic Rules for Logical Assignments Predefined Variables Global Variables Timing Modes “Apply” versus “Program All Channels” Fixed Output Mode Passive Mode (Output = Input) Clocked Pulse Stream Mode Delayed Pulse After Trigger Mode Important Delay Timing Considerations Validated Trigger Input Mode (Noise Suppression) Timer Mode Dynamically-Delayed Pulse Mode...

  • Page 5: Introduction

    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.

  • Page 6: Basic Functions

    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.

  • Page 7: 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.

  • Page 8: Field Upgradeable Software

    (800) 234-7858, or e-mail us at info@berkeleynucleonics.com. 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,...

  • Page 9: 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.

  • Page 10: Front Panel Controls

    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.

  • Page 11: Software Interface

    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.
  • Page 12 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.

  • Page 13: General Settings

    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”...

  • Page 14: Lock/Unlock Panel

    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).

  • Page 15: Channel Properties

    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.

  • Page 16: Quiescent States

    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.

  • Page 17: 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.

  • Page 18: Logic Assignments

    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. Model 725 inputs are TRUE by default if nothing is connected (i.e., the input is NOTE:...

  • Page 19: Parsing

    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.

  • Page 20: Experimenting With Channel Logic

    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.

  • Page 21: Rules For Logical Assignments

    12. Lastly, change the logic assignment to: inA = not in1 and not in2; 13. Click the Set All Channels button. The LED at Output A will remain off until both switches are closed. Rules for Logical Assignments The following rules apply to logical assignments: Logic is case-sensitive.
  • Page 22 1 through 8 from the rear BNC connectors. outA–outG: outputs of channels A through G that appear at the rear BNC connectors. The output of channel H is not internally connected to the logic processor. It...

  • Page 23: Global Variables

    Global Variables “Local Variables” are those that are used directly in logic assignments, such as “inA” or “out1.” Logical assignments that are used repeatedly in your experiment can be stored as “global variables.” With global variables, complex logic is easier to read and debug. Several channels in your experiment may need to be triggered by the same event.
  • Page 24 To create a new global variable, type the variable’s name followed by its definition. In this example we’ve defined variables named “arm” and “fire.” Be sure to end your definition with a semicolon. Click Apply to save the variable.

  • Page 25: Timing Modes

    In the previous section you learned that logic defines how channels are triggered. In this section you’ll use the Model 725 timing modes to determine how the channels will respond. Each channel can be configured to operate in one of eight modes:...

  • Page 26: Apply" Versus "Program All Channels

    Apply. Clicking the OK button will also have the same effect. Logic settings are sent and saved in the Model 725, but any changes are not implemented on the Model 725 until you click Set All Channels button or choose Program>Program All Channels.

  • Page 27: Fixed Output Mode

    Fixed Output Mode In this mode, the channel output remains in the selected state (Low or High), regardless of the input. The front panel LED for the channel will glow green when the output is low or red when the output is high.

  • Page 28: Passive Mode (Output = Input)

    Passive Mode (Output = Input) In passive mode, the output signal equals the input signal or its logical inverse. The front panel LED for the channel will glow green when the output is Low or red when the output is high. To try passive mode: On Channel A’s Settings screen, select the Output=Input timing mode.

  • Page 29: Clocked Pulse Stream Mode

    As mentioned earlier, the Model 725 can operate in two internal clock modes: 100 MHz high resolution and 100/64 MHz low resolution (see General Settings: Time Base Settings). In high...
  • Page 30 resolution mode, the clock pulse and duration can range from 0.48 µs to 52.4 ms. In low resolution mode, pulse and duration can range from 30.1 µs to 3.35 s. To set the duration of the high state, select the timing units (seconds, microseconds, milliseconds or nanoseconds) from the pop-up, then enter a duration in the Clock high duration box.

  • Page 31: Delayed Pulse After Trigger Mode

    Delayed Pulse After Trigger Mode Upon receiving an input signal, a delayed pulse after trigger waits a specified delay time, then sends a pulse to the channel output. This mode has several property tabs. Delay On the Delay tab you’ll specify: The delay between a valid trigger and an output signal Delay after trigger The duration of the output signal...
  • Page 32 100 (high res mode) 100/64 (low res mode) 20 ns to 21.47 s 1.28 µs to 1374 s Delay range 7.7 µs to 21.47 s 493 µs to 1374 s Duration range 10 ns 640 ns Delay / Duration resolution Triggering This tab lets you control how the channel will trigger: The channel can retrigger an unlimited number of times...
  • Page 33 Reset button on the Model 725 or choose Program>Reset Channels in timerPRO. Sets the channel to be edge triggered. In other words, an input signal Trigger on rising input that stays high triggers the channel only once.
  • Page 34 6. Click Apply. 7. Go “online” and click Program > Program all channels. 8. Click the external trigger button (connected via BNC cable). One second after you push it, the output of Channel A will go high for 500 ms.
  • Page 35 A properties screen—the channel LED glows green and you can once again trigger the channel. 10. On the Triggering tab, choose Retrigger N times, set N=5, then click Apply. Depress and hold the external trigger button. As long as the trigger is depressed (i.e., the input signal is high) the channel will continue to trigger until the limit is reached.

  • Page 36: Important Delay Timing Considerations

    Important Delay Timing Considerations Once the Model 725 has begun a delay sequence, it ignores incoming trigger pulses. There is also a delay of approximately 10 μs after the completion of a delay sequence while the channel resets for the next trigger. This effect can be used to skip triggers, but if misunderstood it can cause unexpected results.

  • Page 37: Validated Trigger Input Mode (Noise Suppression)

    Validated Trigger Input Mode (Noise Suppression) The noise suppression function eliminates false triggers due to noise on the input signal by requiring the signal to remain high (or low) for a specified duration. If the signal drops out during that period, the output will remain low and the channel will look for the next input signal. Once an input signal is deemed “valid,”...
  • Page 38 Retrigger N times 2,147,483,647). To allow a channel to be triggered again after reaching the limit, press the Reset button on the Model 725 or choose Program > Reset Channels in timerPRO. While the input is high, channel can be repeatedly triggered.
  • Page 39 7. Go “online” and click Program > Program all channels. 8. Now, depress the external trigger button (connected via BNC). If you hold the button down for more than one second (the minimum duration), the output of Channel A will go high.

  • Page 40: Timer Mode

    Timer Mode The timer mode determines the time delay between two separate input signals and reports it back to the PC. You can view the counter output in the Properties tab. Use the channel’s logic to select the input signals that will be compared by the counter (see Channel Properties: Logic above).
  • Page 41 (e.g., >1000 measurements per second). When you first run the Model 725, channels that are configured as counters NOTE: are initially disabled and must be enabled either by clicking the Enable button on the channel’s Properties screen, or by using the front panel (See Experimenting:...

  • Page 42: Dynamically-Delayed Pulse Mode

    10. On Channel A’s properties screen click Enable. The time difference measurements should now appear, in rapid succession, in the Last Measured Period box on Channel A. The Model 725 may be measuring time differences faster than it can display NOTE: them all on the monitor.
  • Page 43 Scaling In the calculation of the delay, the measured delay between two pulses is scaled by a factor of 2 where –16 < N < 16, or N/16, where 0< N < 256. The former scaling is faster and a scaling of 1:1 is fastest.
  • Page 44 Delay Set an offset value to subtract from the scaled delay length. This is Added Delay useful when accounting for camera shutters or other lag times in experimental equipment. The offset value can be positive (shortens the delay time) or negative (lengthens the delay time) and the resolution is set by the time base (e.g., 10 ns).
  • Page 45 To try the dynamically-delayed pulse mode: You can simulate the experiment above using the external trigger button, connected via BNC to In 1, to represent Sensor 1, and a delayed pulse after trigger in Channel B to represent the signal from Sensor 2.
  • Page 46 5. On Channel A’s Logic tab, enter: inA = not in1;. Click Apply. 6. On Channel B’s Properties screen select Delayed Pulse After Trigger mode. 7. On Channel B’s Delay tab set both the Delay after trigger and Duration of pulse to 100 ms. 8.

  • Page 47: Toggled Output Mode

    Toggled Output Mode This mode toggles its output state upon every input pulse. It functions like a flip-flop and is useful for a variety of logical and control purposes. The minimum input-pulse state duration is 10 ns and the edge-to-toggle delay is < 20 ns. The only user settings for this mode are the initial state, which may be either low or high.
  • Page 48 several microseconds with temperature and aging. This drift may be relatively slow, but inconvenient to compensate. Dynamic Delay Compensation mode is useful for taming the timing of these instruments. In this mode, you send a “trigger” pulse when you want to trigger a device, followed by an “indicator” pulse that shows the actual duration of the device’s function, perhaps from a sensor.
  • Page 49 5 ns, the actual delay is incremented by 10 ns every second trigger event. To try the dynamically-delayed compensation mode: To test this mode, you will need an oscilloscope. Setup the Model 725 as shown below: Channel A: Clocked pulse stream: High duration: 10.000 µs;...
  • Page 50 Channel C: Dynamic Delay Compensation: Delay: 2.000 ms; Duration: 10.000 µs Averaging: None (1 trigger) Trigger Input Logic: inC = outA | out B; Connect a cable from Channel A to one oscilloscope input and a cable from Channel B to another oscilloscope input.
  • Page 51 Channel B, which will provide a precision “delayed indicator” pulse. The delay of Channel B will be added to the “Desired Delay” of Channel C. On the oscilloscope you will see that the delay between pulses on Channels A and D always settle precisely to 10 µs (Desired Delay - Channel B delay), when the delay of Channel D is adjusted anywhere between 35 ns to 3.5 µs, simulating drift.

  • Page 53: Running Experiments

    Front Panel Controls and Indicators The front panel of the Model 725 is designed to help you run experiments without computer control. This functionality allows you to program the unit at a workstation, then to move the unit to the experimental environment.
  • Page 54 When a channel is in Fixed Output, Clock Pulse, Output=Input or Toggled timing modes, the green light indicates that the output is currently LOW for that channel. 2. A red light typically indicates that the channel is in the process of triggering. When a channel is in Fixed Output, Clock Pulse, Output=Input or Toggled timing modes, the red light indicates that the output is currently HIGH for that channel.

  • Page 55: All Channel Led

    Channel LEDs provide important information about the channels, but an NOTE: oscilloscope remains a useful tool for diagnosing channel outputs, particularly for high- speed experiments. ALL Channel LED The All Channel LED shows the overall status of the channels. A green LED indicates that the external inputs and outputs are enabled and functioning normally A red LED indicates that the external inputs and outputs are frozen.

  • Page 56: Performing A Front Panel Function

    Occasionally you’ll need to abort an experiment in progress, due to equipment problems, etc. The quickest way to shut down an experiment is to disable the inputs and outputs of the Model 725. To do so, click the Disable button, then click a particular channel button, or the ALL channels button.

  • Page 57: Trigger A Channel

    Store/Recall Settings Profiles As you know, you can store 64 different “Settings Profiles” in the Model 725. A Settings profile includes properties, variables, and logic for each of the eight channels. Storing Settings profiles lets you switch between settings while running an experiment, to test different timing criteria, initial conditions, etc., without re-plugging or reprogramming.
  • Page 58 To recall a setting profile from within timerPRO: Choose Program > Recall Setting… Click on or type in the desired setting (case insensitive). Click Recall. To store a setting profile from within timerPRO: Choose Program > Store Setting… Click on or type in the desired setting (case insensitive). Click Store.

  • Page 59: Glossary

    Channel Settings The logic and timing settings which determine how a channel functions. Com Port A serial port on a PC computer. The Model 725 communicates with the computer via an RS-232 cable connected to a Com port. Controller The Model 725 hardware unit.
  • Page 60 External Clock The “Ext Clk” input on the back of the Model 725 allows the time base to be controlled by an external source. Firmware The internal code of the Model 725 controller. The firmware, as well as the timerPRO software, can be field-upgraded.
  • Page 61 A setting that allows a channel to trigger only after the specified number of input pulses. Store Load a Settings File into the memory of the Model 725. The settings can be recalled later. Sweep In the Delayed Pulse After Trigger timing mode, this settings...
  • Page 62 (or low) for a specified duration. Update Firmware This menu function allows you to upgrade your Model 725’s firmware to the latest version, available at www.berkeleynucleonics.com.
  • Page 63 Model 725 are trademarks of Berkeley Nucleonics Corporation. National Instruments is a registered trademark of National Instruments, Inc. LabView is a trademark of National Instruments, Inc. Microsoft, Windows 2000 and XP are registered trademarks of Microsoft Corporation. Abobe and Acrobat are registered trademarks of Adobe Systems, Inc.

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