LabSmith LC220 User manual

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LC220 Logic Controller
User Guide
Documentation for the LC220™ Controller
and Trig220™ Control Software v. 1.0

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Table of Contents
INTRODUCTION 3
Parts list 3
Specifications 3
Basic functions 4
How you will use the LC220 4
Installing Trig220 Software 5
Setting up the LC220 5
Field upgradeable software 6
Getting help 6
OVERVIEW OF LC220 CONTROLS 7
Inputs and outputs 8
Panel controls 8
TRIG220 SOFTWARE INTERFACE 9
Main screen 9
Time base settings 11
Clock source 11
Clock multiplier 11
Time base 12
General options 12
Disable/enable outputs 12
Lock/unlock panel 12
CHANNEL PROPERTIES 13
Channel properties screen 13
Quiescent states 14
Logic 14
Logic assignments 15
Experimenting With Channel Logic 16
Timing modes 17
“Apply” versus “Program All Channels” 18
Fixed output mode 19
Passive mode (Output = Input) 20
Clocked pulse stream mode 21
Statically delayed pulse mode 22

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Important delay timing considerations 27
Validated trigger input mode (noise suppression) 28
Timer mode 30
Dynamically-delayed pulse mode 31
Toggled output mode 36
RUNNING EXPERIMENTS 37
Storing and recalling experiment files 37
Panel controls and indicators 37
GLOSSARY 41

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INTRODUCTION
The LC220 is a programmable logic and timing controller for coordinating and
synchronizing lab equipment and physical experiments. The LC220 provides
clocks, counters, triggers, and many other useful functions, with up to 5 ns
resolution and 100 ps accuracy.
As you are well aware, controlling and synchronizing 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 LC220 simplifies your control setup, so you can go
about the business of gathering data.
The LC220 consists of two components: Trig220 software and the LC220 logic
and timing controller. Trig220 lets you configure and run experiments from a
simple graphical interface. The LC220 controller provides the connections and
control for your experimental devices.
Parts list
Your LC220 package should include the following items:
1. LC220 controller
2. AC wall transformer
3. Trig220 software installation CD with user’s manual
4. 9-pin RS232 cable
If any parts are missing or damaged please contact LabSmith support.
Specifications
Trig220 software will run on any PC-compatible computer running Microsoft®
Windows®XP, or newer. Drivers for National Instruments’® LabVIEW™
software are also available for download. See http://www.labsmith.com for more
information.
The LC220 includes two TTL-compatible inputs and two TTL-compatible
outputs. Voltages in the range 2.5 –5 V are TTL “highs” and voltages in the

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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 LC220 can be connected to/ disconnected from the PC at any time without
damage to either unit. This ability allows you to program to LC220 at your
computer, then to take the unit to the experiment area for stand-alone use.
Basic functions
The LC220 provides two 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 time base derived from an internal or
external clock, allowing resolution down to 5 ns.
Each channel also includes logic settings which specify the conditions that will
trigger the channel. A channel can be triggered by logical combinations of
signals from the inputs and/or the output of the other channel.
All settings and setting profiles for a particular experiment can be stored as an
experiment file on your computer. Experiment files bear a .tr2 extension.
How you will use the LC220
In most cases, you’ll use the LC220 as follows:
1. Using the Trig220 software, open an existing experiment file, or create a
new file.
2. In Trig220 (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 LC220’s memory.
4. Test your program by simulating triggers and examining the outputs using
the LC220’s channel LEDs and/or an oscilloscope or other diagnostic tool.
5. Plug your experimental equipment to the LC220.

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6. Run the experiment, using the LC220 by itself or leaving it tethered to the
PC.
Installing Trig220 Software
Insert the Trig220 Software disk in your CD-ROM drive and execute the
setup.exe file.
Setting up the LC220
1. Verify that your wall socket provides AC voltages within the range setting
on the wall transformer supplied with the LC220. If the voltage range is not
correct, contact LabSmith ([email protected]) for an alternate. DO
NOT connect the wall transformer to a socket that is beyond the
transformer’s range setting. Plug the transformer into an appropriate
socket and connect the power to the LC220.
2. Connect the 9-pin cable to the back of the LC220 and to a free serial port on
the PC.
3. Press the Power button on the front of the LC220.
4. From your computer, run Trig220.exe to launch the Trig220 software.
5. From within Trig220, select View>Communications options…. The
Communications properties screen will open.
6. Select the port to which the LC220 is connected. The LC220 will
automatically detect the baud rate, which is typically set to 38400. If the
RS232 cable running to your LC220 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 LC220 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.labsmith.com.
Then choose “Update Firmware” on the Actions menu to load data from that file.
Getting help
This guide is your main source for information on operating the LC220 and
Trig220 software. The guide is also available in an Abobe®Acrobat®Portable
Document Format (pdf) file for electronic viewing.
Check the LabSmith web site (www.labsmith.com) for helpful applications notes
and other technical information to help you use the LC220.
If you are unable to find the information you need, please contact our technical
support team at [phone], or e-mail us at [e-mail].
If you need to contact support, please let us know your LC220 serial number
(located on the bottom of the unit) and the version of software you are using. To
determine the software version number, select “About Trig220” from the
Help menu.

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OVERVIEW OF LC220 CONTROLS
The LC220 is the control unit and interface for your experimental equipment.
You will program it using the Trig220 software. Once you’ve designed, tested
and downloaded your program, you can control the LC220 from the computer,
or you can run it in stand-alone mode.
Indicators and controls on the LC220 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 Trig220 software.
LED Indicators:
Channel A
Channel B
Outputs
Inputs
Outputs
PC Link
Power

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Inputs and outputs
The LC220 includes the following connectors:
- a 2.1 mm power jack (center positive) for 6 to 9 V DC, 0.6 A power
source
- a 9-pin RS232 jack to connect to the Com port of your PC
- two channel input BNC jacks (in1 and in2), normally high (5 V)
- two channel output BNC jacks (outA and outB), normally low (0 V)
- in1 doubles as an input jack for an optional external clock source.
The input and output voltages conform to the TTL standards.
Panel controls
There are three buttons on the LC220. Trigger A and trigger B respectively
force channels A and B to be triggered. The effect this has on the channels
depends on the timing mode of the channels. The third button, Reset, causes
both channels to have their timing modes reset. Again, the effect of the reset
depends on the channel settings. These settings are detailed in the following
sections.

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TRIG220 SOFTWARE INTERFACE
Trig220 has been designed exclusively for setup and control of the LC220.
You’ll use Trig220 to set the timing properties and logic for each of the channels
and to set up overall properties for the experiment.
Main screen
When you run Trig220, you’ll be greeted by the Main screen:
NOTE: At start-up, the Main screen will show the default
program, which sets both channel outputs to a fixed low state.
From this screen you’ll control or access all of Trig220’s functions. Most
Trig220 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 (.tr2 files).
The Edit Menu lets you cut, copy and paste text as you edit your
program.
The View menu lets you set up the Trig220 interface. Choose to display
or hide the tool bars and status bar, select the font used in Trigger, and
set up communications with the LC220.
The Actions menu lets you modify the LC220 settings.
2. The buttons are as follows:
The Reset button resets both channels of the LC220. Retriggering
counters and delay settings are reset as well.
The Program all settings button updates the LC220 with all
current settings.
The Online/Offline button toggles between Online and Offline
mode. In Online mode this button is depressed, the Com port is open,
and settings are transferred to the LC220. In Offline mode, this button is
not depressed, the Com port is available for other programs and settings
are not transferred to the LC220. Offline mode is convenient for
developing .tr2 settings without an LC220 attached.
The Main window panel shows and controls all of the channel settings.
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.

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Time base settings
The “Time base settings” dialog lets you control the time base used by the
LC220 for timing. The LC220 measures, delays, and pulses in increments of this
time base. For higher timing resolution, you can use a higher clock multiplier.
For longer delays, select a lower clock multiplier. A variety of multipliers are
available to optimize the increment for your needs. To reach this screen, click
“Set time base options…” from the Action menu.
Clock source
The LC220 can derive its time base from an internal 25 MHz oscillator or from a
TTL pulse train provided to In1. If the time base is derived from the external
input, you must specify the frequency of this time base so that Trig220 can set
the LC220 timing correctly. If the clock frequency specified is 10% higher than
actual, the channels using this time base will be 10% long on delays and
duration.
Clock multiplier
The clock source is multiplied by a user-specified factor to form a high-
frequency source for the time base. For example, a multiplier of 4 X on the 25
MHz internal oscillator produces a clock of 100 MHz for a time base of 10 ns.

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Time base
The calculated time base is indicated in this window. This must not be less than
5 ns or greater than 1000 ns for proper operation.
General options
The “General options” dialog lets you enable and disable the channel outputs
and lock or unlock the panel buttons. To open this dialog, click “Set LC220
options…” under the Actions menu.
Disable/enable outputs
Disabling outputs prevents the LC220 from sending trigger pulses to its output
connectors regardless of the inputs or the actions of the channels. Enabling the
outputs allows the LC220 to send trigger pulses to its output connectors. These
functions are nonvolatile: the enabled and disabled states are restored on power
cycle.
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 LC220 should function only in stand-alone or computer-
controlled modes. When the panel is locked the buttons are not illuminated.
When the panel is unlocked, the front-panel buttons are illuminated.
Like the enable/disable I/O functions, these settings are nonvolatile and are
restored on power up.

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CHANNEL PROPERTIES
Channel properties screen
Both channels have a Settings screen in the main application window in which
you’ll select the timing mode, set the timing properties, and establish the logic
that will determine when the channel will trigger.
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:

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-Enable restores channel functions following a temporary disable. The
front panel LED for that channel will glow to indicate the channel's
status.
-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).
-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
LC220 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.
Logic
A channel can be triggered by logical combinations of signals from the inputs
and/or other channel output. Channel logic determines the combination of
signals that triggers the channel.
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 select a trigger logic assignment for the channel from a list of
options.

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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 its input.
Logic assignments
The logic processor assigns the logical combination of external inputs (In1 and
In2) and other channel output that will trigger each channel. Logic assignments
have the following format:
[the channel to be triggered] = [the conditions that will trigger it].
Here is an example:
InB = In2.
This assignment means, “Channel B will be triggered when the signal on In2
goes TRUE (reaches ~5 V).”

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The assignment:
InB = Not In2
means “Channel B will trigger when the signal on In2 goes FALSE (drops below
0.2 V).”
You can employ compound arguments in logical assignments, such as:
InB = Not OutA And In2.
This means, “Channel B will trigger when the output of Channel A is FALSE
and In2 is TRUE.”
NOTE: LC220 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.
Experimenting With Channel Logic
This brief example will show you more about channel logic:
1. Connect a normally-open switch to In1 and another to In2.
2. Connect an LED to OutA.
3. Choose “Output = Input” from the “Timing mode” list for Channel A.
In this mode, the output of Channel A is always the same as its input.
4. Select the “Passive” tab and choose “Output = Input.”
5. Select the “Logic” tab and select
inA = in1.
6. Click the “Program all settings” button .
The OutA LED should be glowing, indicating that the output is TRUE, or
HIGH (since LC220 inputs are normally HIGH). When you close Switch 1
the LED will turn off, indicating that the output is FALSE, or LOW.

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NOTE: The Channel A LED on the LC220 glows green while the
channel output is LOW, or red when the output is HIGH. But don’t be
confused! 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.
7. Next, change the logic assignment to
InA = Not In1.
8. Click the “Program All Settings” button . The LED at Output A
will now remain off until you close the switch.
9. Change the logic assignment to
InA = Not In2.
10. Click the “Program All Settings” button. The LED at Output A will
remain off until you close Switch 2.
11. Lastly, change the logic assignment to:
InA = Not In1 And Not In2;
12. Click the “Program All Channels” button. The LED at Output A will
remain off until both switches are closed.
Timing modes
In the previous section you learned that logic defines how channels are triggered.
In this section you’ll use the LC220 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)
-Statically delayed pulse
-Clocked pulse stream
-Validated trigger input (Noise suppression mode)

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-Dynamically delayed pulse
-Timer
-Toggled output.
When a timing mode is selected, the relevant property tabs will be displayed.
NOTE: All timing property tabs include a space for Notes. These notes
are saved and appear in the Main Screen program summary area. It is
good practice to document your settings extensively. As with all
programming, good documentation will simplify the process of
creating, debugging and running your experiments.
For each timing mode you’ll be able to set up a simple example to view the
output of the channel.
To set up for the experiments later in this section:
1. Make sure that the LC220 is connected to the PC.
2. Plug a normally open push-button trigger switch into In1. The button will
represent our triggering “event.”
3. Open Channel A’s Setting screen, and select the “Statically delayed
pulse” timing mode (you’ll learn about Statically delayed pulse mode
shortly).
4. Select the “Logic” tab and select the logical assignment:
InA = Not In1.
Then click Apply. With this logic, Channel A will trigger when you
depress the trigger button.
5. Plug an oscilloscope to Output A to observe the channel output.
Remember, the output voltage will vary from 0 to 5 V.
“Apply” versus “Program All Channels”
Each properties screen includes an “Apply” button which, when clicked, will
send the current timing properties to the channel on the LC220. The other
channel function, for example retriggering counters and triggering, is not
affected.

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“Program All Channels” updates the time base settings and all the channel
settings of the LC220. Both channels are reset.
Fixed output mode
In this mode, the channel output remains in the selected state (Low or High),
regardless of the input.
The 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.” 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.