LabSmith LC880 User Manual

LC880 Experiment Controller

User Guide

Documentation for the LC880™ Controller

and Trigger™ Control Software v. 5.0

Trigger software ©1996--2002 LabSmith.
This manual ©2002 LabSmith. No part of this document may be reproduced or distributed without the consent of LabSmith.

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INTRODUCTION 5

Parts List 5
Specifications 5
Basic Functions 5
How You’ll Use the LC880 6
Installing Trigger Software 6
Setting Up the LC880 6
Getting Help 7

OVERVIEW OF LC880 CONTROLS 8

Back Panel Inputs and Outputs 8
Front Panel Controls 9

TRIGGER SOFTWARE INTERFACE 10

Main Screen 10
General Settings 11

Disable/Enable I/O 11
Lock/Unlock Panel 11
Time base settings 12

CHANNEL PROPERTIES 13

Channel Properties Screen 13
Quiescent States 14
Timing Modes 14

“Apply” versus “Program All Channels” 15
Fixed Output Mode 15
Passive Mode (Output = Input) 16
Clocked Pulse Stream Mode 17
Delayed Pulse After Trigger Mode 18
Validated Trigger Input Mode (Noise Suppression) 21
Counter/Timer Mode 23
Dynamically-Delayed Pulse Mode 25
Toggled Output Mode 28

Logic 28

Predefined Variables 30
Global Variables 31
Parsing 31
Sending Logic 31

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RUNNING EXPERIMENTS 33

Storing and Recalling Experiment Files 33
Front Panel Controls and Indicators 33

Channel LEDs 33
ALL Channel LED 33

Selecting a Channel from the Front Panel 34
Performing a Front Panel Function 34

Enable/Disable ALL 35
Enable/Disable Channel 35
Trigger a Channel 35
Reset 35

Store/Recall Settings Profiles 36

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INTRODUCTION

The LC880 is a fully programmable logic and timing controller for coordinating and synchronizing lab equipment
and physical experiments. LC880 provides clocks, counters, triggers, and many other useful functions, with 10 ns
resolution and 100 ps accuracy.

As you are well aware, controlling and synchronizing your experimental equipment are often the most tedious tasks
you’ll face in the lab. Experimenters regularly build their own controls from scratch or piece together systems from
the limited offerings on the market. The LC880 simplifies your control setup, so you can go about the business of
gathering data, and making knowledge.

The LC880 consists of two components: Trigger software and the LC880 experiment controller. Trigger lets you
design and run experiments from a simple graphical interface. The LC880 controller provides the connections and
control for your experimental devices.

Parts List

Your LC880 package should include the following items:

1. the LC880 controller

2. AC power cable

3. Trigger software installation CD

4. 9-pin RS232 cable

5. User’s manual

If any parts are missing or damaged please contact LabSmith support.

Specifications

Trigger software will run on any PC-compatible computer running Microsoft® Windows® 95, 98, Me, NT, 2000 or
XP. Drivers for National Instruments’® LabView® software are also available for download. See

http://www.labsmith.com for more information.

The LC880 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 LC880 can be connected to/ disconnected from the PC at any time without damage to either unit. This ability
allows you to program to LC880 at your computer, then to take the unit to the experiment area for stand-alone use.

Basic Functions

The LC880 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 triggers, etc. You can set various properties for each timing mode—for example, the delay length on a
Delayed 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 Trigger can be transferred and stored in the memory of the LC880.
You can store up to 64 variations of these properties in settings profiles in the LC880. You can then switch between

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settings profiles to switch experiments, compare different timing scenarios, or simulate different real world
conditions.

All settings and settings profiles for a particular experiment can be stored as an experiment file on your computer.
Experiment files bear a .trg extension.

How You’ll Use the LC880

In most cases, you’ll use the LC880 as follows:

1. Using the Trigger software, open an existing experiment file, or create a new file.

2. In Trigger (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 LC880’s memory.

4. Test your program by simulating triggers and examining the outputs using the LC880’s channel LEDs, an

oscilloscope or other diagnostic tool.

5. Store variations of the channel properties in one of the 64 settings profiles in the LC880.

6. Plug your experimental equipment to the LC880.

7. Run the experiment, using the LC880 by itself or leaving it tethered to the PC. Switch between settings profiles

during the experiment to handle or simulate various timing conditions.

Installing Trigger Software

Insert the Trigger Software disk in the CD-ROM drive and execute the setup.exe file.

Setting Up the LC880

1. Plug the power cable from the back of the unit into a 110–250 VAC power outlet.

2. Connect the 9-pin cable to the back of the LC880 and to a free serial port on your PC.

3. Press the Power button on the front of the LC880.

4. From your computer, run Trigger.exe to launch the Trigger software.

5. From within Trigger, select View>Options>Com Port. The Serial Communications screen will open.

6. Select the port to which the LC880 is connected. The LC880 will automatically detect the baud rate, which is

typically set to 38400. If the RS232 cable running to your LC880 is greater than 30m long, you may need to
lower the baud rate to achieve reliable communication.

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Getting Help

This guide is your main source for information on operating the LC880 and Trigger software. The guide is also
available in an Adobe® Acrobat® Portable Document Format (pdf) file for electronic viewing.

While running Trigger, press F1 to view this document on-line. Or, press SHIFT-F1, then select a button or menu
option to view help topics for a particular feature.

The LabSmith web site (www.labsmith.com) also includes helpful applications notes and other technical information
to help you use the LC880.

If you are unable to find the information you need, please contact our technical support team at [phone], or e­mail us at [e-mail].

If you need to contact support, please let us know the version of software you are using. To determine the software
version number, select “About Trigger” from the Help menu.

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OVERVIEW OF LC880 CONTROLS

The LC880 is the control unit and interface for your experimental equipment. You will program it using the Trigger
software. Once you’ve designed, tested and downloaded your program, you can control the LC880 from the
computer, or you can run it in stand-alone mode.

Indicators and controls on the LC880 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 Trigger software.

Back Panel Inputs and Outputs

Channel Inputs

Channel Outputs

The back panel includes the following connectors:

- an internally-fused jack for a standard 110–250 VAC power cord

- a 9-pin RS232 jack to connect to the Comm port of your PC

- eight BNC channel input jacks (in1–in8), normally-high (5 Volts)

- eight BNC channel output jacks (outA–outH), normally low (0 Volts)

- 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.

Clock Input

RS232 PC Input

110-220 VAC

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Front Panel Controls

Power Switch

Power LED

Channel LEDs

Channel Buttons

Function Buttons

The LC880 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 a steady color . When it glows a steady green, the front panel is unlocked and accepting button pushes.
When it glows red, the front panel is locked. When the front panel is locked, even the power switch is deactivated,
providing security against accidental 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). Some
useful exceptions will be discussed in the Timing modes section below.

The All Channel LED shows the status for all channels. A green LED indicates that the LC880 will respond to
external inputs and that external outputs are active. A red LED indicates that the LC880 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.

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TRIGGER SOFTWARE INTERFACE

Trigger has been designed exclusively for setup and control of the LC880. You’ll use Trigger 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 Trigger, you’ll be greeted by the Main screen:

From this screen you’ll control or access all of Trigger’s functions. Most Trigger 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.

1. Menu options:

The File menu lets you open, close and save experiment files. Trigger files bear a .trg suffix.
The Edit Menu lets you cut, copy and paste text as you edit your program.
The View menu lets you set up the Trigger interface. Choose to display or hide the tool bars and status bar,

select the font used in Trigger, and set up communications with the LC880.

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 LC880. You can send logic, send

properties, reset all channels, or enable/ disable the LC880’s inputs and outputs.

2. The buttons are as follows:

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The General Settings button opens the General Settings screen.

The Channel buttons open the Settings screens for all channels.

1. The Program button updates the LC880 with all current settings.

2. The Reset button resets all channels of the LC880. Retriggering Counters and delay settings will be

reset as well.

3. The Main window panel shows a text summary of all of the settings that have been entered. 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 LC880 control bar can be hidden or displayed by clicking View>LC880.

General Settings

The “General Settings” screen lets you control functions that affect all channels of the LC880. To reach this screen,
click the “General Settings” button, or choose “General” from the Channel menu.

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 LC880. 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 state are restored on power cycle.

You can also disable or enable inputs and outpus from the LC880 front panel (see Experimenting: Disable/Enable
All).

Lock/Unlock Panel

You may lock or unlock the front panel buttons using the “Lock Panel” and “Unlock Panel” buttons. This ability
comes in handy for example in embedded control applications where the LC880 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, this LED glows green and front-panel buttons are illuminated.

Like the enable/disable IO functions, these settings are nonvolatile and are restored on power up. Because the power
button is disabled, the LC880 must be disconnected from AC power to turn it off, if the front panel is locked.

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Time base settings

Each pair of channels of the LC880 can independently utilize one of four different time bases so you can control and
measure events that occur a few nanoseconds apart, or a few hundred seconds apart.

In “100” MHz time base mode (the default) , the LC880 aligns signals to an internal 100 MHz clock, for timing
resolution of 10 ns. Use this “hi-res.” mode when the events of your experiment occur in rapid succession
(milliseconds or less).

“100/64” MHz time base mode allows the LC880 to control events that occur over longer time periods (milliseconds
to minutes). This mode is called “low-res.” 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 input on the back of the LC880. This allows multiple LC880s
to be synchronized to the same time base, high-precision external time bases to be used, or variable-frequency time
bases to be used. This time base cannot be produced by a channel using the 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. For example, if this setting is 10% higher than actual, the channels using this time base will be 10%
long on delays and durations.

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