Berkeley Nucleonics Corporation Model 725 Multi-Trigger Digital Delay Generator User Guide Documentation for the Model 725 and timerPRO Software
TABLE OF CONTENTS INTRODUCTION Parts List Specifications Basic Functions How You Will Use the Model 725 Installing timerPRO Software Setting Up the Model 725 Field Upgradeable Software Getting Help OVERVIEW OF MODEL 725 CONTROLS Back Panel Inputs and Outputs Front Panel Controls SOFTWARE INTERFACE Main Screen General Settings Disable/Enable I/O Lock/Unlock Panel Time base settings 5 5 5 6 6 6 7 8 8 9 9 10 11 11 13 13 14 14 CHANNEL PROPERTIES 15 Channel Properties Screen Quiescent States Logic 15 16 17
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 Toggled Output Mode Dynamic Delay Compensation Mode RUNNING EXPERIMENTS Storing and Recalling Experiment Files Front Panel
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.
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.
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.
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.
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.
Front Panel Controls Power Switch Power LED Channel LEDs Channel Buttons Function Buttons 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.
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.
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.
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.
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.
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.
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).
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.
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.
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.
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.
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. Use lowercase and capital letters as in the samples above. - Spaces matter. Use spaces per the samples above. - If a logical assignment consists of more than one line, each line should end in a carriage return.
- inA–inH: the input of channels A through H. These signals only appear internally at the input of the timing channel; they are not connected to the rear BNCs. These symbols can only be on the left-hand side of an assignment - in1–in8: inputs 1 through 8 from the rear BNC connectors. - outA–outG: outputs of channels A through G that appear at the rear BNC connectors. NOTE: The output of channel H is not internally connected to the logic processor.
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. For example, Channels F, G and H must trigger when: (in1 or in2) and (outC or outD).
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.
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: - Fixed output - Output=Input (Passive Mode) - Delayed Pulse After Trigger - Clocked Pulse Stream - Validated Trigger Input (Noise Suppression) - Dynamically Delayed Pulse - Timer - Toggled Output.
Then click OK. With this logic, Channel A will trigger when you depress the external trigger button (connected via BNC cable). 5. Now transfer the logic to the Model 725 by clicking the Set All Channels button 6. Plug an oscilloscope to Output A to observe the channel output. Remember, the output voltage will vary from 0 to 5 V. .
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. To try fixed output mode: On the Properties tab of Channel A, choose Fixed Output from the pop-up. Choose Low or High as the output state, then click Apply to save the settings. At Output A, the signal will remain a steady TTL logic low or high, depending on your selection.
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. In the Function box, choose Output=Input, then Click Apply to save the settings. When the external trigger button is not depressed (i.e.
Clocked Pulse Stream Mode In clock mode, the output of the channel is a steady stream of pulses. You set the pulse duration and delay between pulses. A clock channel’s input does not affect its output. The front panel LED for a clock channel will glow green when the output is low or red when the output is high. NOTE: For a high-frequency clock the LED will alternate between red and green so quickly that it will appear as a continuous pale green, yellow or orange light.
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. To set the duration of the low state, select the units, then enter the duration in the Clock low duration box.
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 range Duration range Delay / Duration resolution 100 (high res mode) 20 ns to 21.47 s 7.7 µs to 21.47 s 10 ns 100/64 (low res mode) 1.28 µs to 1374 s 493 µs to 1374 s 640 ns Triggering This tab lets you control how the channel will trigger: Normal The channel can retrigger an unlimited number of times Skip N triggers The channel triggers only after the specified number of input pulses (between 0 and 2,147,483,647).
reaching the limit, press the Reset button on the Model 725 or choose Program>Reset Channels in timerPRO. Trigger on rising input Sets the channel to be edge triggered. In other words, an input signal that stays high triggers the channel only once. Trigger on input high Allows the channel to be repeatedly triggered while an input is high. This setting could be used for generating a low-precision gated clock, for example.
To facilitate time-delay scanning experiments, the delay of the pulse relative to the trigger can be “swept” or incremented by a specified value each time the channel is triggered. The sweep value must be positive. The increment resolution is 5 ns. However, the actual delay is rounded to the nearest 10 ns at full internal clock. For example if the increment is set to 5 ns, the actual delay is incremented by 10 ns every second trigger event.
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. 11. Click the Reset button on the Channel A properties screen. 12. Again on the Triggering tab, select Rising Input (Edge Trigger) then click Apply.
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. For example, in the diagram below, two trigger pulses arrive 100 μs apart.
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,” a pulse of user-specified duration will be sent to the channel output.
Duration of pulse The duration of the output signal Until Reset The output will remain high after a valid trigger, until the channel is reset Inverted Output Check the box to set the output high until a valid trigger. On the Triggering tab choose: Normal The channel can retrigger an unlimited number of times Skip N triggers The channel triggers only after the specified number of valid input pulses (between 0 and 2,147,483,647).
To try validated trigger mode: 1. On the General Settings screen, select 100/64 (low-resolution) mode for Channels A and B. 2. Click OK to save the change. A warning may appear listing channels for which the clock range settings are invalid. Click OK to close the warning. The software will go into “offline” mode allowing you to adjust the timing settings for the listed channels. 3. In Channel A’s properties screen, select Validated Trigger Input mode. 4.
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). For example, if the logic reads “in1 and in2;” the counter will determine the time delay between a pulse at Input 1 and the next pulse from Input 2.
NOTE: To switch from counter mode, first click the Disable button and ensure the channel LED is unlit, indicating that the channel is disabled. This will help you avoid unexpected behaviors when the counter is transmitting measurements rapidly (e.g., >1000 measurements per second).
6. On Channel A’s Logic tab, enter: inA = outB and outC; (You’ll learn more about channel logic in the Logic section above). 7. On Channel A’s Counter tab, select milliseconds as the units. 8. Click Disable, then click Apply. 9. Lastly, go “on line” and click Send Logic on the Main screen to update the new logic for all channels. 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.
Scaling In the calculation of the delay, the measured delay between two pulses is scaled by a factor of 2N, where –16 < N < 16, or N/16, where 0< N < 256. The former scaling is faster and a scaling of 1:1 is fastest. Scaling can typically be done at rates > 50 kHz. The maximum delay between input pulses is 52 ms in hi-res mode (100 MHz) and 3.3 s in low-res mode (100/64). The maximum delay resulting from the scaling and offset calculations is respectively 21.47 s and 1374 s in hi-res and low-res modes.
Delay Added Delay Set an offset value to subtract from the scaled delay length. This is 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).
Triggering The triggering options are the same as those for Delayed Pulse After Triggering mode: Normal The channel can retrigger an unlimited number of times Skip N triggers The channel triggers only after the specified number of input pulses (between 0 and 2,147,483,647). Retrigger N times Limits the number of retriggers allowed between resets (between 0 and 2,147,483,647).
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. On Channel B’s Triggering Tab select Normal to allow retriggering. 9. On Channel B’s Logic tab enter: inB = outA; This logic will cause the delayed trigger to pulse 100 ms after a signal from Channel A. 10. Click Apply. 11.
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. The front panel LED for the channel will glow green when the output is low or red when the output is high.
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. The channel measures the actual delay between the trigger pulse and the indicator pulse.
Desired delay The delay between the trigger and response signals that timerPRO will attempt to maintain. Duration of pulse The duration of the output signal Inverted Output Check to set the output high until the next valid trigger. Averaging Delay Averaging Determines how the delay compensation will be calculated. Choose None to calculate a new delay compensation time with each trigger pulse; or, choose to use an average compensation based on the last 2 to 256 trigger pulses.
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. If you have more channels, you can also connect Channel C to the oscilloscope.
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. It may take several seconds before you observe the settling of the delay because of the Averaging value of 256 triggers.
RUNNING EXPERIMENTS Once you’ve created a program you’re ready to set up and perform your experiment. Storing and Recalling Experiment Files As mentioned earlier, an experiment file is a document which resides on your PC, containing all of the logic, properties, and settings profiles for a particular experiment. Experiment files bear the .trg extension. To save an experiment, choose File>Save As. Name the file, then store it on your hard drive in an accessible place.
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. 3.
NOTE: Channel LEDs provide important information about the channels, but an oscilloscope remains a useful tool for diagnosing channel outputs, particularly for highspeed 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. (See Running Experiments: Disable/ Enable channels below).
Performing a Front Panel Function Front panel functions can be accessed in one of two ways: - select a channel (or ALL channels), then choose a function - select a function, then choose a channel (or ALL channels). There is no significant difference between these two approaches. In the image below, the Enable button has just been pushed. The channel buttons and the ALL channel button are lit. Pressing one of these buttons will now enable the channel(s).
Trigger a Channel This function lets you simulate an input trigger on a channel, regardless of the channel’s logic settings. This is a useful way to initiate a timing sequence without actually performing the live experiment. You can also trigger a channel from within the timerPRO software (See Channel Properties: Force Trigger above). NOTE: You cannot trigger ALL channels, only individual channels. Reset The Reset button returns the selected channel or ALL channels to the last programmed settings.
To recall a setting profile from within timerPRO: 1. Choose Program > Recall Setting… 2. Click on or type in the desired setting (case insensitive). 3. Click Recall. To store a setting profile from within timerPRO: 1. Choose Program > Store Setting… 2. Click on or type in the desired setting (case insensitive). 3. 58 Click Store.
GLOSSARY Apply Sends a channel’s current timing settings to the Model 725. Baud Rate The speed of communication via the Com port. Channel One of eight internal signal paths in the Model 725. Channel Input The signal which feeds one of the eight channels. A channel input can be triggered by signals from any combination of signals from the input jacks and/or channel outputs. Channel Settings The logic and timing settings which determine how a channel functions.
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. Latest upgrades are available at www.berkeleynucleonics.com. General Settings The settings which govern the function of all channels. Global Variable A shorthand symbol for a logical assignment that may be used repeatedly throughout a program.
Predefines A set of standard variables and operators that can be used in logic assignments. Program All Channels A function which sends all logic and timing settings to the Model 725. Programmable Logic Controller A device which combines logic and timing processors for precise control of physical experiments. Recall Re-loads a stored Settings File. Reset Returns all channels of the Model 725 to their waiting condition. Retriggering Counters and delay settings are reset as well.
Trigger An input signal that initiates a channel function. timerPRO (software) The control software for the Model 725. Trigger Validation Mode Also known as “Noise Suppression” mode. This timing mode eliminates false triggers due to noise on the input signal by requiring the signal to remain high (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.
timerPRO and 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. This manual © 2008 Berkeley Nucleonics Corporation. No part of this document may be reproduced or distributed without the consent of Berkeley Nucleonics.
