All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or
transmitted, in any form by any means, electronic, mechanical, by photocopying, recording, or
otherwise without the prior written permission of Meilhaus Electronic GmbH.
Important note:
All the information included in this user’s gide were put together with utmost care and to best
knowledge. However, mistakes may not have been erased completely.
For this reason, the firm Meilhaus Electronic GmbH feels obliged to point out that they cannot be take
on neither any warranty (apart from the claims for warranty as agreed) nor legal responsibility or
liability for consequences caused by incorrect instructions.
We would appreciate it if you inform us about any possible mistakes.
The trademark Personal Measurement Device, TracerDAQ, Universal Library, InstaCal, Harsh
Environment Warranty, Measurement Computing Corporation, and the Measurement Computing logo
are either trademarks or registered trademarks of Measurement Computing Corporation.
Windows, Microsoft, and Visual Studio are either trademarks or registered trademarks of Microsoft
Corporation.
LabVIEW is a trademark of National Instruments.
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All other trademarks are the property of their respective owners.
.
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Table of Contents
Preface
About this User's Guide .......................................................................................................................6
What you will learn from this user's guide .........................................................................................................6
Conventions in this user's guide .........................................................................................................................6
Where to find more information.........................................................................................................................6
Chapter 1
Introducing the RedLab 1008...............................................................................................................7
Unpacking the RedLab 1008 ............................................................................................................................11
Installing the software ......................................................................................................................................11
Installing the hardware .....................................................................................................................................11
USB connector.................................................................................................................................................................14
Status LED.......................................................................................................................................................................14
Digital I/O connector and pin out.....................................................................................................................................15
Main connectors and pin outs ..........................................................................................................................................18
Analog input terminals (CH0 In - CH7 In) ......................................................................................................................18
Digital I/O terminals (DIO0 - DIO3) ...............................................................................................................................21
Power terminals ...............................................................................................................................................................22
Channel gain queue ..........................................................................................................................................25
Digital connector cabling..................................................................................................................................26
Analog Input.....................................................................................................................................................28
Analog output ...................................................................................................................................................29
Digital input / output (screw terminal DIO3:0) ................................................................................................30
Digital input / output (DB37) ...........................................................................................................................30
General .............................................................................................................................................................32
Main connector and pin out..............................................................................................................................32
DB37 connector and pin out.............................................................................................................................33
5
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Preface
About this User's Guide
What you will learn from this user's guide
This user's guide explains how to install, configure, and use the RedLab 1008. This guide also refers you to
related documents available on our web site, and to technical support resources.
Conventions in this user's guide
For more information on …
Text presented in a box signifies additional information and helpful hints related to the subject matter you are
reading.
Caution! Shaded caution statements present information to help you avoid injuring yourself and others,
damaging your hardware, or losing your data.
<#:#> Angle brackets that enclose numbers separated by a colon signify a range of numbers, such as those assigned
to registers, bit settings, etc.
bold text Bold text is used for the names of objects on the screen, such as buttons, text boxes, and check boxes. For
example:
1. Insert the disk or CD and click the OK button.
italic text Italic text is used for the names of manuals and help topic titles, and to emphasize a word or phrase. For
example:
The InstaCal installation procedure is explained in the Quick Start Guide.
Never touch the exposed pins or circuit connections on the board.
Where to find more information
The following electronic documents provide helpful information relevant to the operation of the RedLab 1008.
The Quick Start Guide is available on our RedLab CD in the root directory.
The Guide to Signal Connections is available on our RedLab CD under „ICalUL\Documents“.
The Universal Library User's Guide is available on our RedLab CD under „ICalUL\Documents“.
The Universal Library Function Reference is available on our RedLab CD under „ICalUL\Documents“.
The Universal Library for LabVIEW
„ICalUL\Documents“.
™
User’s Guide is available on our RedLab CD under
6
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Chapter 1
Introducing the RedLab 1008
This user's guide contains all of the information you need to connect the RedLab 1008 to your computer and to
the signals you want to measure.
The RedLab 1008 is a USB 1.1 low-speed analog and digital I/O device that is supported under popular
Microsoft
2.0 ports.
The RedLab 1008 features eight 12-bit analog input signal connections and 28 digital I/O connections. It is
powered by the +5 volt USB supply. No external power is required.
Two screw terminals rows provide connections for eight analog inputs, two 10-bit analog outputs, four
bidirectional digital I/O lines, and one 32-bit external event counter. You can configure the analog input
connections with software as either four single-ended or eight differential channels. All analog connections
terminate at the screw terminals.
24 bidirectional digital I/O lines are also available on a 37-pin connector.
An on-board industry standard 82C55 programmable peripheral interface chip provides 24 digital I/O lines that
terminate at a 37-pin connector.
The RedLab 1008 USB device is shown in Figure 1.
®
Windows® operating systems. The RedLab 1008 is fully compatible with both USB 1.1 and USB
Figure 1. RedLab 1008
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RedLab 1008 User's Guide Introducing the RedLab 1008
RedLab 1008 block diagram
RedLab 1008 functions are illustrated in the block diagram shown here.
Screw Terminal
I/O Connector
4 Auxillary
DIO Bits
USB1.1
Compliant
Interface
USB
Microcontroller
82C55
DIO
DB37 I/O Connector
12-Bit
Analog Input
8 SE / 4 Diff.
10-Bit
Analog Output
2 channel
32-Bit Event
Counter
Software features
For information on the features of InstaCal and the other software included with your RedLab 1008, refer to the
Quick Start Guide that shipped with your device. The Quick Start Guide is also available in PDF on our RedLab
CD in the root directory.
Figure 2. RedLab 1008 Functional Block Diagram
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RedLab 1008 User's Guide Introducing the RedLab 1008
Connecting a RedLab 1008 to your computer is easy
Installing a data acquisition device has never been easier.
The RedLab 1008 relies upon the Microsoft Human Interface Device (HID) class drivers. The HID class
drivers ship with every copy of Windows that is designed to work with USB ports. We use the Microsoft
HID because it is a standard, and its performance delivers full control and maximizes data transfer rates for
your RedLab 1008. No third-party device driver is required.
The RedLab 1008 is plug-and-play. There are no jumpers to position, DIP switches to set, or interrupts to
configure.
You can connect the RedLab 1008 before or after you install the software, and without powering down
your computer first. When you connect an HID to your system, your computer automatically detects it and
configures the necessary software. You can connect and power multiple HID peripherals to your system
using a USB hub.
You can connect your system to various devices using a standard four-wire cable. The USB connector
replaces the serial and parallel port connectors with one standardized plug and port combination.
You do not need a separate power supply module. The USB automatically delivers the electrical power
required by each peripheral connected to your system.
Data can flow two ways between a computer and peripheral over USB connections.
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Installing the RedLab 1008
What comes with your RedLab 1008 shipment?
As you unpack your RedLab 1008 device, verify that the following components are included:
Hardware
RedLab 1008 device
Chapter 2
USB cable
Additional documentation
In addition to this hardware user's guide, you should also receive the Quick Start Guide (available on our
RedLab CD (root directory)). This booklet supplies a brief description of the software you received with your
RedLab 1008 and information regarding installation of that software. Please read this booklet completely before
installing any software or hardware.
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RedLab 1008 User's Guide Installing the RedLab 1008
Unpacking the RedLab 1008
As with any electronic device, you should take care while handling to avoid damage from static
electricity. Before removing the RedLab 1008 from its packaging, ground yourself using a wrist strap or by
simply touching the computer chassis or other grounded object to eliminate any stored static charge.
If your RedLab 1008 is damaged, notify Measurement Computing Corporation immediately by phone, fax, or email. For international customers, contact your local distributor where you purchased the RedLab 1008.
Phone: +49 (0) 89/8901660
Fax: +49 (0) 89/89016628
E-Mail: support@meilhaus.com
Installing the software
Refer to the Quick Start Guide for instructions on installing the software Guide (available on our RedLab CD
(root directory)).
Installing the hardware
Be sure you are using the latest system software
Before you connect the RedLab 1008, make sure that you are using the latest versions of the USB drivers.
Before installing the RedLab 1008, download and install the latest Microsoft Windows updates. In particular,
when using Windows XP, make sure you have XP Hotfix KB822603 installed. This update is intended to
address a serious error in Usbport.sys when you operate a USB device. You can run Windows Update or
download the update from www.microsoft.com/downloads/details.aspx?familyid=733dd867-56a0-4956-b7fe-
e85b688b7f86&displaylang=en. For more information, refer to the Microsoft Knowledge Base article
"AvailabilityoftheWindowsXPSP1USB1.1and2.0update." This article is available at
support.microsoft.com/?kbid=822603.
To connect the RedLab 1008 to your system, turn your computer on, and connect the USB cable to a USB port
on your computer or to an external USB hub that is connected to your computer. The USB cable provides power
and communication to the RedLab 1008.
When you connect the RedLab 1008 for the first time, a
or dialog (other Windows version) displays as the RedLab 1008 is detected by your computer.
Another FoundNew Hardware balloon or dialog opens after the first closes that identifies the RedLab 1008 as
a USB Human Interface Device. This balloon or dialog indicates that your RedLab 1008 is installed and ready
to use.
Found New Hardware popup balloon (Windows XP)
When the balloon or dialog closes, the LED on the RedLab 1008 should flash and then remain lit. This indicates
that communication is established between the RedLab 1008 and your computer.
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RedLab 1008 User's Guide Installing the RedLab 1008
Caution! Do not disconnect any device from the USB bus while the computer is communicating with the
RedLab 1008, or you may lose data and/or your ability to communicate with the RedLab 1008.
If the LED turns off
If the status LED is illuminated but then turns off, the computer has lost communication with the RedLab 1008.
To restore communication, disconnect the USB cable from the computer, and then reconnect it. This should
restore communication, and the LED should turn back on.
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Chapter 3
Functional Details
Theory of operation - analog input acquisition modes
The RedLab 1008 can acquire analog input data in three different modes – software paced, continuous scan, and
burst scan.
Software paced mode
In software paced mode, the RedLab 1008 gathers data in a single acquisition or as a group of single
acquisitions. An analog-to-digital conversion is initiated with a software command, and the single data point
result is returned to the host. This operation may be repeated until the required number of samples is obtained
for the channel (or channels) in use. Software pacing is limited by the 20 mS round-trip requirement of a USB
interrupt-type endpoint operation. This yields a maximum throughput in software paced mode of 50 S/s.
Continuous scan mode
In continuous scan mode, the RedLab 1008 gathers data in a single-channel or multi-channel sequence. This
sequence converts, transfers, and stores data to a user buffer until the scan is stopped. In this mode, digitized
data is continuously written to an on-board FIFO buffer. This FIFO is serviced in blocks as the data is
transferred from the RedLab 1008 to the user buffer in the host PC.
The maximum continuous scan rate of 1.2 kS/s is an aggregate rate. The total acquisition rate for all channels
cannot exceed 1.2 kS/s. You can acquire data from one channel at 1.2 kS/s, two channels at 600 S/s and four
channels at 300 S/s. You can start a continuous scan with either a software command or with an external
hardware trigger event.
Burst scan mode
In burst scan mode, the RedLab 1008 gathers data using the full capacity of its 4 K sample FIFO buffer. You
can initiate a single acquisition sequence of one, two, or four channels by either a software command or an
external hardware trigger. The captured data is then read from the FIFO and transferred to a user buffer in the
host PC.
Since the data is acquired at a rate faster than it can be transferred to the host, burst scans are limited to the
depth of the on-board memory. As with continuous mode, the maximum sampling rate is an aggregate rate.
Consequently, the maximum burst mode rates are 8 kS/s, 4 kS/s and 2 kS/s for one, two and four channels,
respectively.
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RedLab 1008 User's Guide Functional Details
p
p
g
External components
The RedLab 1008 has the following external components, as shown in Figure 3.
USB connector
Status LED
Digital I/O connector
Screw terminal banks (2)
ital I/O connector
Di
STATUS LED
Pin 1
Pin 16
Screw terminal
ins 1 to 15
Pin 15
USB connector
Figure 3. RedLab 1008 external components
Screw terminal
ins 16 to 30
USB connector
The USB connector is located on the bottom edge of the RedLab 1008. This connector provides +5 V power
and communication. The voltage supplied through the USB connector is system-dependent, and may be less
than 5 V. No external power supply is required.
Caution! The USB +5V Out pins on the DB37 connector are outputs. Do not connect an external 5 V supply
or you may damage the RedLab 1008 and possibly the computer.
Status LED
The STATUS LED on the front of the RedLab 1008 indicates the communication status. It uses up to
5 milliamperes (mA) of current and cannot be disabled. The table below explains the function of the RedLab
1008 LED.
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RedLab 1008 User's Guide Functional Details
LED Illumination
When the LED is… It indicates…
Steady The RedLab 1008 is connected to a computer or external USB hub.
Blinks continuously Data is being transferred.
Blinks three times Initial communication is established between the RedLab 1008 and the computer.
Blinks at a slow rate
The analog input is configured for external trigger. The LED stops blinking and illuminates
steady green when the trigger is received.
Digital I/O connector and pin out
Digital I/O connections are made to the DB37 connector on the top edge of the RedLab 1008. This connector
provides connections for 24 digital lines (
output terminals (
USB +5V Out). Refer to Figure 4 and the table below for the DB37 connector pin out.
Digital I/O connections (Port A0 through Port C7)
Port A0 to Port C7), six ground connections (GND), and two power
The 24 digital I/O pins (
Port A0-A7, Port B0-B7 and Port C0-C7) are TTL-level compatible. Each pin has a
47 kilohm (kΩ) pull-up resistor and is configured as an input by default. If needed, the RedLab 1008 can be
factory configured to provide pull-down resistors.
Caution! Port A0 through Port C7 have no overvoltage/short circuit protection. Do not exceed the voltage
limits or you may damage the pin or the RedLab 1008. To protect these pins, you should use a series
resistor.
37
19
Figure 4. DB37 Digital I/O connector
DB37 connector pin out
Pin Signal Name Pin Signal Name
1 n/c 20 USB +5V Out
2 n/c 21 GND
3 Port B7 22 Port C7
4 Port B6 23 Port C6
5 Port B5 24 Port C5
6 Port B4 25 Port C4
7 Port B3 26 Port C3
8 Port B2 27 Port C2
9 Port B1 28 Port C1
10 Port B0 29 Port C0
11 GND 30 Port A7
12 n/c 31 Port A6
13 GND 32 Port A5
14 n/c 33 Port A4
15 GND 34 Port A3
16 n/c 35 Port A2
17 GND 36 Port A1
18 USB +5V Out 37 Port A0
20
1
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RedLab 1008 User's Guide Functional Details
Pin Signal Name Pin Signal Name
19 GND
Refer to the "Digital connector cabling
digital I/O connector. (Phone:: +49 (0)89/890166-0, Fax: +49 (0)89/890166-28 or E-Mail: info@meilhaus.de
" section for descriptions of cables that are compatible with the DB37
.
Caution! The USB +5V Out pins on the DB37 connector are outputs. Do not connect an external 5 V supply
or you may damage the RedLab 1008 and possibly the computer.
Screw terminal wiring
The RedLab 1008 has two rows of screw terminals. Each row has 15 connections. Pin numbers are identified in
Figure 5. The pins are labeled for eight-channel single-ended mode operations.
Pin 1
Pin 16
Pin 15 Pin 30
Figure 5. RedLab 1008 screw terminals
Screw terminal pins 1-15
The screw terminals on the left edge of the RedLab 1008 (pins 1 to 15) provide the following connections:
Eight analog input connections (
Four GND connections (
GND)
One calibration terminal (
Two power connectors (
PC +5 V)
CH0 IN to CH7 IN)
CAL)
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RedLab 1008 User's Guide Functional Details
Screw terminal pins 16-30
The screw terminals on the right edge of the RedLab 1008 (pins 16 to 30) provide the following connections:
Four digital I/O connections (
Two analog output connections (
DIO0 to DIO3)
D/A OUT 0 to D/A OUT 1)
One external event counter connection (
One testing and calibration terminal (
Five ground connections (
Two power connectors (
GND)
PC +5 V)
TST)
CTR)
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RedLab 1008 User's Guide Functional Details
Main connectors and pin outs
Connector type
Wire gauge range
4-channel differential mode pin out
Note that the pins are labeled for 8-channel
single-ended mode on the RedLab 1008.
8-channel single-ended mode pin out
Screw terminal
16 AWG to 26 AWG
CH0 IN HI1
CH0 IN LO2
GND3
CH1 IN HI4
CH1 IN LO5
GND6
CH2 IN HI7
CH2 IN LO8
GND9
CH3 IN HI10
CH3 IN LO11
GND12
PC +5 V13
PC +5 V14
CAL15
Connect up to eight analog input connections to the screw terminal connections labeled CH0 In through CH7 In.
Refer to the pinout diagrams
on page 18 for the location of these pins.
You can configure the analog input channels as eight single-ended channels or four differential channels. When
configured for differential mode, each analog input has 12-bit resolution. When configured for single-ended
mode, each analog input has 11-bit resolution, due to restrictions imposed by the A/D converter.
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RedLab 1008 User's Guide Functional Details
Single-ended configuration
When all of the analog input channels are configured for single-ended input mode, eight analog channels are
available. In single-ended mode, the input signal is referenced to signal ground (GND). The input signal is
delivered through two wires:
The wire carrying the signal to be measured connects to CH# IN.
The second wire connects to GND.
The input range for single-ended mode is ±10 V max, with a gain of 2. No other gains are supported in singleended mode.
Figure 6 illustrates a typical single-ended measurement connection.
CH0
+
1.5
-
CH1 (differential configuration)
GND
Figure 6. Single-ended measurement connection
Single-ended measurements using differential channels
To perform a single-ended measurement using differential channels, connect the voltage to an analog input with
an even-number, and ground the associated odd-numbered analog input. This configuration is shown in Figure
6.
Differential configuration
When all of the analog input channels are configured for differential input mode, four analog channels are
available. In differential mode, the input signal is measured with respect to the low input.
The input signal is delivered through three wires:
The wire carrying the signal to be measured connects to CH<0, 2, 4, 6> IN. In differential mode, the even
numbered channels are considered HI inputs. Hence, CH0 IN, CH2 IN, CH4 IN and CH6 IN are considered
HI input channels.
The wire carrying the reference signal connects to CH<1, 3, 5, 7> IN. In differential mode the odd
numbered channels are considered the LO input. Hence, CH1 IN, CH3 IN, CH5 IN and CH7 IN are
considered LO input channels.
The third wire connects to GND.
When should you use a differential mode configuration?
Differential input mode is the preferred configuration for applications in noisy environments, or when the signal
source is referenced to a potential other than PC ground.
A low-noise precision programmable gain amplifier (PGA) is available on differential channels to provide gains
of up to 20 and a dynamic range of up to 16-bits.
In differential mode, the following two requirements must be met for linear operation:
Any analog input must remain in the −10 V to +20 V range with respect to ground at all times.
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RedLab 1008 User's Guide Functional Details
The maximum differential voltage on any given analog input pair must remain within the selected voltage
range.
The input [common-mode voltage + signal] of the differential channel must be in the −10 V to +20 V range in
order to yield a useful result.
For example, you input a 4 volt peak-to-peak (Vpp) sine wave to CHHI, and apply the same sine wave 180° out
of phase to CHLO. The common mode voltage is 0 V. The differential input voltage swings from 4 V-(-4 V) =
8 V to -4 V-4 V = -8 V. Both inputs satisfy the -10 V to +20 V input range requirement, and the differential
voltage is suited for the ±10 V input range (see Figure 7).
+4V
CHHI
0V
-4V
Measured Signal
8V Differential
+4V
CHLO
-4V
+/-8V
Figure 7. Differential voltage example: common mode voltage of 0 V
If you increase the common mode voltage to 11 V, the differential remains at ±8 V. Although the [commonmode voltage + signal] on each input now has a range of +7 V to +15 V, both inputs still satisfy the -10 V to
+20 V input requirement (see Figure 8).
+15V
CHHI
CHLO
+11V
8V Differential
+11V
+7V
+/-8V
Figure 8. Differential voltage example: common mode voltage of 11 V
Measured Signal
If you decrease the common-mode voltage to -7 V, the differential stays at ±8 V. However, the solution now
violates the input range condition of -10 V to +20 V. The voltage on each analog input now swings from -3 V to
-11 V. Voltages between -10 V and -3 V are resolved, but those below -10 V are clipped (see Figure 9).
-3V
CHHI
-7V
-11V
8V Differential
-3V
-7V
CHLO
-11V
Figure 9. Differential voltage example: common mode voltage of -7 V
Measured Signal
3V
+/-7V
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RedLab 1008 User's Guide Functional Details
Since the analog inputs are restricted to a −10 V to +20 V signal swing with respect to ground, all ranges except
±20 V can realize a linear output for any differential signal with zero common mode voltage and full scale
signal inputs. The ±20 V range is the exception. You cannot put −20 V on CHHI, and 0 V on CHLO, since this
violates the input range criteria. The next table shows some possible inputs and the expected results.
Sample inputs and differential results
CHHI CHLO Result
-20 V 0 V Invalid
-15 V +5 V Invalid
-10 V 0 V -10 V
-10 V +10 V -20 V
0 V +10 V -10 V
0 V +20 V -20 V
+10 V -10 V +20 V
+10 V 0 V +10 V
+15 V -5 V +20 V
+20 V 0 +20 V
Additional information on analog signal connections
For general information regarding single-ended and differential inputs, refer to the Guide to Signal Connections
(available on our RedLab CD under „ICalUL\Documents“).
Digital I/O terminals (DIO0 - DIO3)
Connect up to four digital I/O lines to the screw terminals containing pins DIO0 to DIO3. Refer to the pinout
diagrams on page 18 for the location of these pins. You can configure each digital channel independently for
either input or output.
Overvoltage/short circuit protection is provided with a 1.5 kΩ series resistor on each I/O pin. Use of the resistor
may limit the value of the output current, however. For example, if the output current is 1 mA, the resistor drops
1.5 V, resulting in an output of 3.5 V.
You can use the digital I/O terminals to detect the state of any TTL level input. In Figure 10, if the switch is set
to the +5 V input, and the DIO0 reads TRUE (1). If the switch is moved to GND, the DIO0 reads FALSE.
DIO0
+5V+GND
Figure 10. Digital connection DIO0 detecting the state of a switch
Additional information on digital signal connections
For general information regarding digital signal connections and digital I/O techniques, refer to the Guide to
Signal Connections (available on our RedLab CD under „ICalUL\Documents“).
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RedLab 1008 User's Guide Functional Details
Power terminals
The PC +5V connections on the screw terminal draw power from the USB connector. The +5 V screw terminal
is a 5 volt output that is supplied by the computer.
Caution! The PC +5V terminals are outputs. Do not connect an external power supply to a +5 V screw
terminal, or you may damage the device and possibly the computer.
The maximum total output current that can be drawn from all RedLab 1008 connections (power, analog and
digital outputs) is 500 mA. This maximum applies to most personal computers and self-powered USB hubs.
Bus-powered hubs and notebook computers may limit the available output current to 100 mA.
Just connecting the RedLab 1008 to your computer draws 20 mA of current from the USB +5V supply. Once
you start running applications with the device, each DIO bit can draw up to 2.5 mA, and each analog output can
draw 30 mA. The maximum amount of +5 V current available to the user is the difference between the total current requirement of the PMD (based on the application), and the allowed current draw of the PC platform
(again, 500 mA for desktop PCs and self-powered hubs, or 100 mA for bus-powered hubs and notebook
computers).
With all outputs at their maximum output current, you can calculate the total current requirement of the RedLab
1008 device's USB +5 V as follows:
(RedLab 1008 @ 20 mA) + (28 DIO @ 2.5 mA) + (2 AO @ 30 mA) =150 mA
For an application running on a PC or powered hub, this value yields a maximum user current of
500 mA − 150 mA = 350 mA. This number is the total maximum available current at the PC +5 V screw
terminals. Measurement Computing highly recommends that you figure in a safety factor of 20% below this
maximum current loading for your applications. A conservative, safe user maximum in this case would be in the
280 mA range.
Since laptop computers typically allow up to 100 mA, the RedLab 1008 in a fully-loaded configuration may be
above that allowed by the computer. In this case, you must determine the per-pin loading in the application to
ensure that the maximum loading criteria is met. The per-pin loading is calculated by simply dividing the +5V
by the load impedance of the pin in question.
Ground terminals
There are nine identical ground connections that provide a common ground for all RedLab 1008 functions.
Refer to the pinout diagrams
on page 18 for the location of the GND terminal pins.
Calibration terminal
The CAL connection on the output terminal provides a calibration reference voltage. This terminal should only
be used during calibration of the RedLab 1008 device.
Calibration of the RedLab 1008 is software-controlled via InstaCal.
Testing terminal
The TST terminal is reserved for factory testing only.
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RedLab 1008 User's Guide Functional Details
e
Counter terminal
The input connection to the 32-bit external event counter is made to the screw terminal labeled CTR. Refer to
the pinout diagrams on page 18 for the location of this pin. The internal counter increments whenever the CTR
input voltage changes from <1 volt to more than 4 volts. The counter is capable of counting frequencies up to
1 MHz.
Accuracy
The overall accuracy of any instrument is limited by the error components within the system. Quite often,
resolution is incorrectly used to quantify the performance of a measurement product. While "12-bits" or "1 part
in 4096" does indicate what can be resolved, it provides little insight into the quality of an absolute
measurement. Accuracy specifications describe the actual results that can be realized with a measurement
device.
There are three types of errors which affect the accuracy of a measurement system:
offset
gain
nonlinearity
The primary error sources in the RedLab 1008 are offset and gain. Nonlinearity is small in the RedLab 1008,
and is not significant as an error source with respect to offset and gain.
Figure 11 shows an ideal, error-free, RedLab 1008 transfer function. The typical calibrated accuracy of the
RedLab 1008 is range-dependent, as explained in the "Specifications
" chapter of this document. We use a ±10
V range here as an example of what you can expect when performing a measurement in this range.
Inpu t Volta ge
+FS
Output Cod
0
Figure 11. Ideal ADC transfer function
2048
-FS
4095
The RedLab 1008's offset error is measured at mid-scale. Ideally, a zero-volt input should produce an output
code of 2048. Any deviation from this is an offset error. Figure 12 shows the RedLab 1008 transfer function
with an offset error. The typical offset error specification on the ±10 V range is ±9.77 millivolts (mV). Offset
error affects all codes equally by shifting the entire transfer function up or down along the input voltage axis.
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RedLab 1008 User's Guide Functional Details
e
V
The accuracy plots in Figure 12 are drawn for clarity and are not drawn to scale.
Input Volta ge
+FS
Id ea l
2
2048
9.77mV
Output Cod
4095
0
Ac t ua l
Offset= 9.77mV
-FS
Figure 12. ADC transfer function with offset error
Gain error is a change in the slope of the transfer function from the ideal, and is typically expressed as a
percentage of full-scale. Figure 13 shows the RedLab 1008 transfer function with gain error. Gain error is easily
converted to voltage by multiplying the full-scale (FS) input by the error.
The accuracy plots in Figure 13 are drawn for clarity and are not drawn to scale.
Inpu t Vol ta ge
+FS
Idea l
Gai n e rror= + 0 .2 %, o r + 2 0 m
Gai n e rror= -0 .2%, o r -2 0 m V
Ac t ua l
0
For example, the RedLab 1008 exhibits a typical calibrated gain error of ±0.2% on all ranges. For the ±10 V
range, this would yield 10V × ±0.002 = ±20 mV. This means that at full scale, neglecting the effect of offset for
the moment, the measurement would be within 20 mV of the actual value. Note that gain error is expressed as a
ratio. Values near ±FS are more affected from an absolute voltage standpoint than are values near mid-scale,
which see little or no voltage error.
Output Code
2048
4095
-FS
Figure 13. ADC Transfer function with gain error
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RedLab 1008 User's Guide Functional Details
Combining these two error sources in Figure 14, we have a plot of the error band of the RedLab 1008 for the
±10 V range. This is a graphical version of the typical accuracy specification of the product.
The accuracy plots in Figure 14 are drawn for clarity and are not drawn to scale
Idea l + 9.77m V + 20 mV
Idea l
Idea l -(9.77mV + 20 mV)
Inpu t Volta ge
9.77mV
0
Figure 14. Error band plot
+FS
2048
-FS
Ideal + 9.77mV + 20 mVIdeal + 9.77mV + 20 mV
Ideal
Idea l -(9.77m V + 20 m V)
Output Code
4095
Channel gain queue
The RedLab 1008's channel gain queue feature allows you to set up a scan sequence with a unique per-channel
gain setting and channel sequence.
The channel gain queue feature removes the restriction of using an ascending channel sequence at a fixed gain.
This feature creates a channel list which is written to local memory on the RedLab 1008. This list is made up of
a channel number and range setting. An example of a four-element list is shown in the table below.
Sample channel gain queue list
Element Channel Range
0 CH0 BIP10V
1 CH0 BIP5V
2 CH7 BIP10V
3 CH2 BIP1V
When a scan begins with the gain queue enabled, the RedLab 1008 reads the first element, sets the appropriate
channel number and range, and then acquires a sample. The properties of the next element are then retrieved,
and another sample is acquired. This sequence continues until all elements in the gain queue have been selected.
When the end of the channel list is detected, the sequence returns to the first element in the list.
This sequence repeats until the specified number of samples is gathered. You must carefully match the gain to
the expected voltage range on the associated channel—otherwise, an over range condition can occur. Although
this condition does not damage the RedLab 1008, it does produce a useless full-scale reading. It can also
introduce a long recovery time from saturation, which can affect the next measurement in the queue.
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RedLab 1008 User's Guide Functional Details
Digital connector cabling
Table 3-1 lists the digital I/O connector, applicable cables and accessory equipment. The x in the compatible
cable name indicates the length in feet of the cable.
Table 3-1. Digital connector and accessory equipment
Connector type 37-pin D-type, shielded
Compatible cables
Compatible accessory products CIO-MINI37
C37FF-x (Figure 15)
C37FFS-x (Figure 16)
C37FM-x (Figure 17)
SSR-RACK24
SSR-RACK08
CIO-ERB24
CIO-ERB08
19
The red stripe
1
20
37
identifies pin # 1
19
1
20
37
Female connectorFemale connector
Figure 15. C37FF-x cable
1
19
20
37
1
19
20
37
Figure 16. C37FFS-x cable
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RedLab 1008 User's Guide Functional Details
The red stripe
1
20
37
19
identifies pin # 1
20
37
1
19
Female connectorMale connector
Figure 17. C37FM-x cable
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Chapter 4
Specifications
Typical for 25 °C unless otherwise specified.
Specifications in italic text are guaranteed by design.
Analog Input
Parameter Conditions Specification
A/D converter type Successive approximation type
Input voltage range for linear operation,
single-ended mode
Input voltage range for linear operation,
differential mode
Absolute maximum input voltage CHx to GND ±40 V max