MED Associates SG-231 User manual

instrumentation and software for research
28V DC TO TTL ADAPTER
SG-231
USER’S MANUAL
DOC-203
Rev. 1.6
Copyright ©2020
All Rights Reserved
Med Associates, Inc.
P.O. Box 319
St. Albans, Vermont 05478
Phone: [phone]
Fax: [phone]
www.med-associates.com

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MED A SSOCIAT E S, INC.
SG
-
231 28V DC TO TTL
ADAPTER
- iii - DOC-203 Rev. 1.6 Copyright © 2020
Med Associates, Inc.
Table of Contents
Chapter 1 | Introduction ................................................................................................ 1
Specs: .............................................................................................................................................. 1
Chapter 2 | Hardware ..................................................................................................... 2
Configuration 1 .............................................................................................................................. 2
Configuration 2 .............................................................................................................................. 3
Operate LED ................................................................................................................................... 3
28V Input Connector ..................................................................................................................... 4
Med Input Connector .................................................................................................................... 4
TTL Outputs .................................................................................................................................... 5
Chapter 3 | TTL Output Setting .................................................................................... 6
Appendix A | Contact Information ............................................................................... 7

MED A SSOCIAT E S, INC.
SG
-
231 28V DC TO TTL
ADAPTER
- iv - DOC-203 Rev. 1.6 Copyright © 2020
Med Associates, Inc.
Notes
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Diagrams

MED A SSOCIAT E S, INC. SG-23 1 2 8V DC TO T TL ADAPTE R
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Med Associates, Inc.
CHAPTER 1 | INTRODUCTION
The SG-231 is a 28V DC to TTL adapter allows the user to send TTL signals from Med Associates devices
such as response levers, head entry detectors, nose pokes, etc. (Configuration 1).
The SG-231 also allows the user to send TTL signals programmatically, using a Med Associates Interface
and software (Configuration 2).
TTL signals are typically used to synchronize with a third party acquisition interface, operate a TTL
device, or log event markers in a data acquisition system.
Our latest model includes 2 TTL outputs; 1 BNC TTL output and 1 Screw Terminal TTL output. The user
can use either one individually or both simultaneously to trigger 2 TTL devices at the same time.
Specs:
17mA @ Idle
21mA @ Operation
Figure 1.1 – SG-231 28V DC to TTL Adapter

MED A SSOCIAT E S, INC. SG-23 1 2 8V DC TO T TL ADAPTE R
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Med Associates, Inc.
CHAPTER 2 | HARDWARE
Configuration 1
This configuration allows the user to send TTL signals from a Med Associates device in a standalone or
custom application.
In this configuration the SG-231 requires an input from a 28V DC power source and a Med Associates
device, such as a retractable lever (both sold separately). See Figure below.
Figure 2.1 – SG-231 Configuration 1

MED A SSOCIAT E S, INC. SG-23 1 2 8V DC TO T TL ADAPTE R
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Med Associates, Inc.
Configuration 2
This configuration allows the user to convert the 28V DC signal from an available output on a powered
Med Associates Connection Panel to a TTL signal.
The SG-231 does not require a 28V DC input in this configuration; the output on the powered
Connection Panel supplies 28V DC. See Figure below.
Figure 2.2 – SG-231 Configuration 2
Operate LED
The Operate LED indicator, Figure 2.3, will illuminate when the unit receives an input signal to operate
the TTL device.
Figure 2.3 - Operate LED Indicator

MED A SSOCIAT E S, INC. SG-23 1 2 8V DC TO T TL ADAPTE R
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Med Associates, Inc.
28V Input Connector
 Configuration 1 - The 28V INPUT connector must be connected to a 28V DC power supply (e.g.
SG-500T).
 Configuration 2 - The 28V INPUT is not required.
Figure 2.4 - 28V Input Connector
Med Input Connector
 Configuration 1 - The INPUT connector is connected to the output of a Med Associates lever,
head entry detector, nose poke device, etc.
 Configuration 2 - The INPUT connector is connected directly to an available output on a
powered Med Associates Connection Panel.
Figure 2.5 - Input Connector

MED A SSOCIAT E S, INC. SG-23 1 2 8V DC TO T TL ADAPTE R
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Med Associates, Inc.
TTL Outputs
TTL OUTPUT BNC: Connect the TTL OUTPUT BNC to the TTL input device.
Figure 2.6 – TTL Output BNC Connector
TTL OUTPUT Screw Terminal: Connect the TTL Output screw terminal to the TTL input device.
TTL GROUND Screw Terminal: Connect to the TTL input device’s ground.
NOTE: Do not connect the TTL Ground connection to the 28V power supply ground. These grounds
must remain isolated.
NOTE: Place fork lugs between screw head and washer.
The optional Med Associates PHM-155G screw terminal to BNC cable makes for convenient connections
to most TTL devices and if 2 BNC connections are desired.
Figure 2.7 - TTL Ground and Output Screw Terminals

MED A SSOCIAT E S, INC. SG-23 1 2 8V DC TO T TL ADAPTE R
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Med Associates, Inc.
CHAPTER 3 | TTL OUTPUT SETTING
The SG-231’s TTL logic jumper is factory set to the Active High (jumper connecting pins 2 and 3).
In the Active High position, the TTL signal will be LOW (~0V) when off and HIGH (~5V) when operated.
To change the TTL logic jumper to the Active Low (Jumper connecting pins 1 and 2), remove the 2 screws
from the bottom of the SG-231, flip over, and lift the top cover off. Near the center of the printed circuit
board is jumper location JP1, see Figure 3.1.
Figure 3.1 – TTL Logic Jumper
Remove the jumper and reposition it to cover pins 1 and 2 as shown in Figure 3.2.
In the Active Low position the TTL signal will be HIGH (~5V) when OFF and LOW (~0V) when operated.
Figure 3.2 - Active High Jumper Setting

MED A SSOCIAT E S, INC. SG-23 1 2 8V DC TO T TL ADAPTE R
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Med Associates, Inc.
APPENDIX A | CONTACT INFORMATION
Please contact Med Associates, Inc. for information regarding any of our products.
For Technical questions, email suppor[email protected].
For Sales questions, email [email protected].
Visit our website at www.med-associates.com.