Multichannel Systems STG1000 User Manual

Stimulus Generator 1000 Series

Manual

Information in this document is subject to change without notice.

No part of this document may be reproduced or transmitted without the express written
permission of Multi Channel Systems MCS GmbH.

While every precaution has been taken in the preparation of this document, the publisher and the
author assume no responsibility for errors or omissions, or for damages resulting from the use of
information contained in this document or from the use of programs and source code that may
accompany it. In no event shall the publisher and the author be liable for any loss of profit or any
other commercial damage caused or alleged to have been caused directly or indirectly by this
document.

© 2011 Multi Chann

el Systems MCS GmbH. All rights reserved.

Printed: 2008-10-10

Multi Channel Syst

ems

MCS GmbH

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72770 Reutlingen

Germany

Fon [phone] - 0

Fax [phone]

[e-mail]

www.multichannelsystems.com

Microsoft and Windows are registered trademarks of Microsoft Corporation. Products that are
referred to in this document may be either trademarks and/or registered trademarks of their
respective holders and should be noted as such. The publisher and the author make no claim to
these trademark.

Table of Contents

Introduction 1

About this Manual 1
Terms of Use for MC_Stimulus 1
Limitation of Liability 1

Important Information and Instructions 3

Operator's Obligations 3
Guaranty and Liability 3
Important Safety Advice 3

First Use of the Stimulus Generator 5

Welcome to the STG and MC_Stimulus 5
Setting Up and Connecting the STG 6
Installing the Software 7

Operating the STG 9

Operation Overview 9
Operating Multiple STGs 10

Programming Stimulus Protocols 11

MC_Stimulus Worksheet 11
Pulse Types 12
Autorepeating Pulses and Protocols 14
Autocreating Entries and Editing Columns 15
Auto Sync for Autocreating Trigger Pulses 22

ASCII Import/Export 25

Loading Files 25
Exporting Files 26
Supported File Formats 26

Stimulus Display 33

Selecting Channels 33
Display Tools 33

Downloading Stimuli 37

Downloading Stimulus Files 37

General Software Features 39

Customizing the Main Window 39
Menu Bar 39
Toolbar 39
Shortcut Keys 40
File Menu 40
Settings Menu 41

Synchronizing Events 43

Digital Output Signals (Sync Out) 43
Triggering Stimulation (Trigger In) 44

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Stimulus Generator 1000 Series User Manual

Batch Mode 45

Analog Output Signals 49

Output Modes 49
Voltage Mode 49
Current Mode 54
Measuring Output Signals with an Oscilloscope 57
Rise Time 58
Amplitude-Dependant Time Lag 61
Capacitive Behavior of Stimulating Electrodes 67

Troubleshooting 69

About Troubleshooting 69
Technical Support 69
Error Messages 69
Strong Peak Artifacts 71
Output Signal Does not Match Programmed Signal 71

Appendix 73

Technical Specifications STG1001/2 73
Technical Specifications STG1004/8 74
Contact Information 75
Ordering Information 75

Index 77

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1 Introduction

1.1 About this Manual

This manual comprises all important information about the installation and operation of the
stimulus generator STG1000 series and MC_Stimulus software. It is assumed that you have already
a basic understanding of technical and software terms. No special skills are required to read this
manual.

If you are using the STG for the first time, please read the important safety advice before
installing the hardware and software (see Important Safety Advice, where you will find
important information about the installation and first steps).

The printed manual and Help are basically the same, so it is up to you which one you will use.
The Help offers you the advantage of scrolling through the text in a non-linear fashion, picking up
all information you need, especially if you use the Index, the Search function, and the Browse
Sequences. If you are going to read larger text passages, however, you may prefer the printed
manual.

The device and the software are part of an ongoing developmental process. Please understand
that the provided documentation is not always up to date. Check also the MCS Web site
(www.multichannelsystems.com) from time to time for downloading up-to-date manuals and new
software versions.

1.2 Terms of Use for MC_Stimulus

You are free to use MC_Stimulus for its intended purpose. You agree that you will not decompile,
reverse engineer, or otherwise attempt to discover the source code of the software.

1.3 Limitation of Liability

Multi Channel Systems MCS GmbH makes no guaranty as to the accuracy of any and all tests and
data generated by the use the MC_Stimulus software. It is up to the user to use good laboratory
practice to establish the validity of his findings.

To the maximum extent permitted by applicable law, in no event shall Multi Channel Systems MCS
GmbH or its suppliers be liable for any special, incidental, indirect, or consequential damages
whatsoever (including, without limitation, injuries, damages for data loss, loss of business profits,
business interruption, loss of business information, or any other pecuniary loss) arising out of the
use of or inability to use MC_Stimulus or the provision of or failure to provide Support Services,
even if Multi Channel Systems MCS GmbH has been advised of the possibility of such damages.

1

2 Important Information and Instructions

2.1 Operator's Obligations

The operator is obliged to allow only persons to work on the device, who

• are familiar with the safety at work and accident prevention regulations and have been instructed
how to use the device;

• are professionally qualified or have specialist knowledge and training and have received
instruction in the use of the device;

• have read and understood the chapter on safety and the warning instructions in this manual and
confirmed this with their signature.

It must be monitored at regular intervals that the operating personnel are working safely.

Personnel still undergoing training may only work on the device under the supervision of an
experienced person.

2.2 Guaranty and Liability

The General conditions of sale and delivery of Multi Channel Systems MCS GmbH always apply.
The operator will receive these no later than on conclusion of the contract.

Multi Channel Systems MCS GmbH makes no guaranty as to the accuracy of any and all tests and
data generated by the use of the device or the software. It is up to the user to use good
laboratory practice to establish the validity of his findings.

Guaranty and liability claims in the event of injury or material damage are excluded when they
are the result of one of the following.

• Improper use of the device

• Improper installation, commissioning, operation or maintenance of the device

• Operating the device when the safety and protective devices are defective and/or inoperable

• Non-observance of the instructions in the manual with regard to transport, storage, installation,

commissioning, operation or maintenance of the device

• Unauthorized structural alterations to the device

• Unauthorized modifications to the system settings

• Inadequate monitoring of device components subject to wear

• Improperly executed and unauthorized repairs

• Unauthorized opening of the device or its components

• Catastrophic events due to the effect of foreign bodies or acts of God

2.3 Important Safety Advice

Warning: Make sure to read the following advice prior to install or to use the device and the
software. If you do not fulfill all requirements stated below, this may lead to malfunctions or
breakage of connected hardware, or even fatal injuries.

Warning: Obey always the rules of local regulations and laws. Only qualified personnel should
be allowed to perform laboratory work. Work according to good laboratory practice to obtain
best results and to minimize risks.

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Stimulus Generator 1000 Series User Manual

The product has been built to the state of the art and in accordance with recognized safety
engineering rules. The device may only

• be used for its intended purpose;

• be used when in a perfect condition.

• Improper use could lead to serious, even fatal injuries to the user or third parties and damage to

the device itself or other material damage.

Warning: The device and the software are not intended for medical uses and must not be used
on humans.

Malfunctions which could impair safety should be rectified immediately.

High Voltage

Electrical cords must be properly laid and installed. The length and quality of the cords must be in
accordance with local provisions.

Only qualified technicians may work on the electrical system. It is essential that the accident
prevention regulations and those of the employers' liability associations are observed.

• Each time before starting up, make sure that the mains supply agrees with the specifications of
the product.

• Check the power cord for damage each time the site is changed. Damaged power cords should
be replaced immediately and may never be reused.

• Check the leads for damage. Damaged leads should be replaced immediately and may never be
reused.

• Do not try to insert anything sharp or metallic into the vents or the case.

• Liquids may cause short circuits or other damage. Keep the device and the power cords always

dry. Do not handle it with wet hands.

Requirements for the installation

• Make sure that the device is not exposed to direct sunlight. Do not place anything on top of the
device, and do not place it on top of another heat producing device. Otherwise, the device may
overheat.

4

3 First Use of the Stimulus Generator

3.1 Welcome to the STG and MC_Stimulus

Product line overview

Stimulus generators of the 1000 and 2000 series are
general/purpose stimulators designed to serve a very wide variety
of applications, both in vitro and in vivo.

Flexible and easy-to-use MC_Stimulus software enables complex
stimulus waveforms (both current and voltage). Waveforms
designed in the program or imported from an external ASCII file
are converted by the connected STGs into pulses, which are sent
to stimulating electrodes. Stimulus isolation units (SIU) for each
channel are included. Thus, no external SIUs are required.

A trigger input and output for TTL signals allows to synchronize the stimulus generator with other
instruments. Triggering of other devices via programmable TTL pulses (Sync Out) is possible, as
well as triggering of the STG by external devices via the Trigger In input. For example, you can
synchronize stimulation and recording with a digital trigger signal sent from the Sync Out
output of the STG to the MC_Card.

Stimulus generators are available for simultaneous stimulation on up to 8 channels
(STG1001STG1008, STG2004, STG2008).

2000 Series

The real-time stimulus generator of the 2000 series is an advanced version and the world's first
STG that is able to send continuous pulse streams to stimulating electrodes. In addition, you can
trigger all (up to 8) channels separately by external TTL pulses. 4 trigger inputs (Trigger In)
and4 trigger outputs (Sync Out) are shared by 8 channels in the 8-channel version.

MC_Stimulus

Stimuli are created user-friendly by entering the desired pulses (rectangular, ramp, or sine
waveforms) into a worksheet. Waveforms can be combined freely to create virtually any stimulus
pattern.

Created stimuli are displayed in a WYSIWYG stimulus display. All channels are set up
separately.

For even more convenience, repetitive stimulus patterns do not have to be entered separately,
but can be grouped and looped. You can also import waveforms in ASCII file format and use
them for stimulation. You can print and save stimuli and comments for later use and
documentation of your experiments.

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Stimulus Generator 1000 Series User Manual

3.2 Setting Up and Connecting the STG

Provide a power supply and a computer with RS232 serial port in the immediate vicinity of the
installation site. Make sure the STG is switched off before you connect it to the power supply.

1. Place the STG on a stable surface, where the air can circulate freely and the STG is not exposed to
direct sunlight.

2. Plug the main cable into the socket on the back of the STG.

3. Connect the main cable to the power outlet.

4. Connect the RS232 connector to the serial port of the computer. The computer connection is
necessary for programming the STG, but not for operating it (except in Batch mode).

5. Connect the required output channels with 2 mm plug cables to the stimulating electrodes. Use
the +U or U outputs for voltage stimuli, and +I or I outputs for current stimuli. Connect the
appropriate ground to the ground input of the stimulation setup, for example to the ground
input of the MEA1060 amplifier. See also chapter "Output Signals" for more information and
illustrations showing suggested setups.

6. (Optional) Connect the required Trigger In input with a BNC cable to an instrument that produces
TTL signals for triggering the STG.

7. (Optional) Connect the required Sync Out output with a BNC cable to a following instrument that
you want to be triggered by TTL signals from the STG, for example to one of the 16 digital inputs
of the MC_Card.

8. Switch the STG on by pressing the toggle switch on the rear panel.

6

3.3 Installing the Software

System requirements

First Use of the Stimulus Generator

Software: One of the following Windows© operating systems is required: Windows 200
Windows

software errors.

Hardware: RS232 serial port

Installing the software

Please check the system requirements before you install the software. MCS cannot guarantee that
the software works properly if these requirements are not fulfilled.

Important: Please make sure that you have full control over your computer as an administrator.
Otherwise, is possible that the installed software does not work properly.

1. Double-click Setup.exe on the installation volume.
The installation assistant will show up and guide you through the installation procedure.

2. Follow the instructions of the installation assistant. Please select the appropriate maximum
number of analog output channels according to the connected STG. If you have different STGs in
use, choose the highest number.

XP (English and German versions supported). Other language versions may lead to

0 or

When you have finished the installation of the MC_Stimulus software, you can now operate the
STG.

7

4 Operating the STG

4.1 Operation Overview

Warning: Make sure that you do not come in contact with the cables or the connectors of the
STG after you have started the STG. The high voltage and power can lead to injuries.

Warning: Do not start the STG if you are unsure about the channel configuration or the nature
of the downloaded file.

1. Set up your experiment.

2. Switch the STG on.

3. Set up your stimuli with the MC_Stimulus program.

4. Send the stimulus sequence from an MC_Stimulus file to the STG.

5. Start the STG either manually by pressing the Start/Stop button on the front panel, with the

software controls, or with an external trigger.

Creating stimuli

Stimuli are created user-friendly by entering the desired pulses (rectangular, ramp, or sine
waveforms) into an MC_Stimulus worksheet. Waveforms can be combined freely to create virtually
any stimulus pattern. Created stimuli are displayed in a WYSIWYG window.

Starting stimulation

Note: You need a computer connection only when you are using the software controls for starting
and stopping the stimulus generator. When you are using the STG interface or an external control
(trigger), you can disconnect the stimulus generator from the computer and operate it
independently. But you cannot remove the STG from the power connection. The memory is
cleared when the STG has lost power.

After the download of the stimulus file on the STG, you can start the stimulation. There are
several ways to start the STG.

MC_Stimulus
interface:

STG
interface:

External
control:

You can start the stimulation directly after the download (with the command
Download and Start (sel.) or Download and Start (all), or also later with
the command Start. You can stop stimulation with the command Stop.

You can start the stimulation by pressing the Start/Stop button on the front
panel of the STG. Press the button again to stop the stimulation.

You can start the stimulation on a trigger from an external device, for example,
a switch. The trigger works the same way as when you press the Start/Stop
button.The STG is stopped when a trigger event occurs during the time when
any channel is still active.

STG status control

Two status control LEDs (light-emitting diode) are present on the front panel of the STG to give
you a quick overview on its status.

POWER Lights yellow during startup. Lights green if STG is on. Lights red if STG is in a bad

state.

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Stimulus Generator 1000 Series User Manual

SWEEP Lights green if stimulus file has been downloaded to STG. STG is now ready to use.

Lights orange when stimulation is running, that is, output channels are active.

4.2 Operating Multiple STGs

If you have more than one STG connected to the same computer, you can choose which STG you
like to control from the currently active MC_Stimulus program.

• The serial port of the currently active STG is displayed on the status bar of the currently active
instance of the MC_Stimulus program.

• Click Port Settings and then select the serial port to which the
selected STG is connected.

• You can open multiple instances of the MC_Stimulus program
and control multiple STGs at the same time. Please make sure
that you control each STG only by one MC_Stimulus instance.

• You can also open only one MC_Stimulus instance and control
multiple STGs one after the other by the same instance. Simply
change the Port Settings and select the next STG when you
have finished to program the first. The STGs can be operated
without a computer connection.

10

5 Programming Stimulus Protocols

5.1 MC_Stimulus Worksheet

You can freely combine any pulse types. Use a separate row for each pulse type.

Hint: Several tools are provided for editing whole columns at once or autocreating entries.

1. Select the desired output type first. Click either Voltage or Current under Output Mode on
the file window of MC_Stimulus.

2. Click a tab to select an output channel.
The according channel worksheet is brought to front.

3. Now you can enter the pulses into the worksheet. Select a Pulse type (either rectangular, ramp,
or sine).

4. Enter the desired voltage steps and a time length for each step.

The according pulse is displayed in the WYSIWYG display at once.

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Stimulus Generator 1000 Series User Manual

5.2 Pulse Types

Three basic pulse types are available in MC_Stimulus. You can create virtually any pulse by
combining different types.

• Rectangular

• Ramp

• Sine wave

Note: The time resolution is 20 μs. When you enter time steps that are not a multiple of 20 μs,
the length of the step is internally adjusted to a valid value. The changed values do not show up
in the worksheet, but invalid values are highlighted in yellow or red. The minimum voltage
resolution is 2 mV, the current resolution is 1 μA. Please regard also the minimum and

maximum output voltage/current of your STG version.

Note: If you work near the resolution limits of the STG, the output pulses may differ from the

programmed pulses. In this case, you should check the output with an oscilloscope. Please see

also the "Analog Output Signals" chapter.

Note: The total pulse length of all channels has to be identical. If the stimuli of two channels
have different lengths of time, the last used value of the shorter channel is kept until the longest
stimulus has been finished. You will be notified with an error message at the beginning of the
download.

Please note that the memory of the STG is limited. You will get an error message if the memory is
full. The new generation of stimulus generators (STG2004/8) has 16 times more memory and an
improved internal memory management, perfect for sophisticated or long-term stimulus
protocols.

For the digital Sync channel, only bit patterns of 0 (LOW) and 1 (HIGH) can be programmed. A
logical state of 1 (HIGH) results in a 5 V output signal, and a logical state of 0 (LOW) results in a 0
V output. Please note that the digital output is sent about 20 μs faster than the analog output.
Please see also the "Triggering Stimulation" chapter.

Rectangular pulse type

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Programming Stimulus Protocols

• Enter each voltage/current level and the duration of the pulse. The voltage/current jumps
directly to the specified level. In one row, you can enter up to three voltage/current levels. Use the
next row for programming more levels.

Ramp pulse type

• Define the starting point, end point, and the length of the ramp. The ramp is then build
according to these parameters in small single steps of 20 μs.

Sine wave pulse type

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Stimulus Generator 1000 Series User Manual

• Define the amplitude and the period of the sine wave. The sine wave is then computed
according to these parameters with a minimum resolution of 2 mV and 20 μs. If you enter a
negative amplitude, the sine wave starts with its negative alternation.

5.3 Autorepeating Pulses and Protocols

For entering complex stimuli easier and faster, you can repeat rows and groups instead of
entering the pulses several times into the worksheet. You can repeat each single row. In the
preceding example, the rectangular pulse in row 1 is repeated twice. You can also group several
rows and repeat them altogether. In the example, pulses from rows 1 to 4 are grouped and
repeated three times.

Repeating rows

• Type the number of repeats into the Row Repeat cell of the appropriate row.
The pulses of the complete row are than repeated the specified number of times.

Grouping and repeating groups

1. Select several cells by clicking and dragging cells in the Group Repeat column.
Selected cells are highlighted in black.

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Programming Stimulus Protocols

2. Point to the selected cells and right-click to open the context menu.

3. Click Group/Ungroup.
The corresponding rows are grouped now. This is indicated by a merging of the Group Repeat
cells.

4. Type the number of repeats into the merged Group Repeat cell.

Repeating complete pulse protocols (autorepeat function), Continuous Mode

1.

2.

You can also repeat all stimuli on all channels, that is, the whole file either continuously (until
stopped manually by the user) or a specified number of times.

• Under Repeat, select continuously for repeating the stimulation until the STG is stopped by the
user.

• Under Repeat, select n times and enter a number for repeating the stimulation n times.

5.4 Autocreating Entries and Editing Columns

Changing time units for a complete column

1. Click any Unit column header to select a column.
The selected column is highlighted in black.

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Stimulus Generator 1000 Series User Manual

2. Right-click and click Change Time Unit.

3. Select the desired time unit.

All units in the column are set to the selected time unit.

Inverting pulses in a column

1. Click any Value column header to select a column.
The selected column is highlighted in black.

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Programming Stimulus Protocols

2. Right-click and click Invert Selection.

The polarity of the signals is switched from positive to negative and vice versa.

Incrementing columns

This feature is very convenient for setting up long and complex stimuli without entering each
value manually. You can enter and edit multiple voltage values or time lengths.

You can keep all zero values unchanged with the option Keep Zero.

Apart from an absolute shift or increment factor, you can modify values by the percentage as
well.

Shifting time or voltage/current values

You enter a value, which is added arithmetically to all values in the selected column. For example,
if you enter "50", 50 is added to all values.

1. Click any Value or Time column header to select a column.
The selected column is highlighted in black.

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Stimulus Generator 1000 Series User Manual

2. Right-click and click Increment Selection.

3. Under Type of Increment, select Shift.

4. Enter the desired value.

All values in the selected column are modified by the selected factor. In the example, 100 is added
to all values, resulting in a total of 100 because the initial value has been 0.

Creating time or voltage/current increments

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Programming Stimulus Protocols

With this option, you enter a base value for modification of all values in the selected column. The
first row is modified by the base value. The second row is modified by the double value, the third
row by thrice the base value, and so on. With this feature, you can easily set up time or voltage
increments.

1. Under Type of Increment, select Count.

2. Enter the desired start value.

The value in the first row is incremented by the selected start value of 10. The next value is
modified by the double value (20), and so on.

You can now fill further columns in the same way. Thus, you can easily set up a stimulus with
incremented pulse lengths like this with only a few mouse-clicks.

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Stimulus Generator 1000 Series User Manual

In the same way, you can set up a stimulus with voltage/current increments.

Shifting absolute time or voltage values

With this option, the signs of the selected values are ignored. Zeros are never changed, that is, the
option Keep Zero cannot be deselected.

1. Under Type of Increment, select Absolute Value.

2. Enter the desired shift factor.

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Programming Stimulus Protocols

The absolute values of 200 and 200 are both 200. This absolute value of 200 is modified by the
shift factor of 50, resulting in 250. The negative value is now 250, and the positive value is 250. (If
you had chosen the option Shift instead, the computed result would have been 200 + 50 = 150.)
All zero values are not changed.

Autocreating entries

You can use the Autofill feature to set up advanced time or voltage/current increments. You
define the Start and End value and either the Step Size (Start - Stop - Step Size) or the
number of Steps (Start - Stop - # of Steps). Alternatively, you can enter the Step Size and the
Number of Steps (Start - Step Size - # of Steps). According to these specifications, rows are
inserted and the column is filled automatically.

In the following example, the Autofill feature has been used to create a voltage step series from
20 mV to 500 mV with an increment of 20 mV.

1. Click any Value or Time column header to select a column.
The selected column is highlighted in black.

2. Right-click and click Autofill.

3. Select one out of three commands and fill in the white text boxes.

The column is filled according to the specifications.

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