Intab PC-Logger 3100i How To Use Manual

How to use

PC-logger 3100i

and

accessories

INTAB Interface-Teknik AB

e-mail: [e-mail]

www.intab.se

3100i-eng.doc

iii

CONTENTS

BASIC UNIT ................................................................................................................5

1 AN OVERVIEW ................................................................................................5

1.1 General .........................................................................................................5

1.2 ”On-line” measurements .............................................................................6

1.3 ”Off-line” measurements.............................................................................6

2 DISPLAY AND KEYS.......................................................................................7

2.1 CLOCK..............................................................................................................7

3 STORAGE CAPACITY....................................................................................8

3.1 Storage capacity in your computer..............................................................8

3.2 Storage capacity in the ”3100i”...................................................................9

4 POWER SUPPLY............................................................................................10

5 INPUTS - RANGES .........................................................................................11

5.1 Preset ranges ..............................................................................................12

5.2 Software Switchable Ranges......................................................................12

5.3 RANGES AND THEIR RESOLUTION .................................................................13

5.4 Temperature measurements - T/C:s..........................................................13

6 CONNECTORS ...............................................................................................16

6.1 Power ..........................................................................................................16

6.2 Computer ....................................................................................................16

6.3 Connecting Sensors and Transducers.......................................................17

7 MISCELLANEOUS ........................................................................................23

7.1 Reset............................................................................................................23

7.2 Program......................................................................................................23

8 TECHNICAL SPECIFICATIONS.................................................................24

8.1 Analog Data................................................................................................24

8.2 Storage Memory .........................................................................................26

8.3 Computer communication..........................................................................26

8.4 Commands..................................................................................................26

8.5 Power ..........................................................................................................27

8.6 Mechanical specifications..........................................................................27

8.7 Environmental conditions..........................................................................27

OPTION: DIGITAL I/O AND PULSE COUNTERS............................................29

1 AN

OVERVIEW ..............................................................................................29

1.1 Digital Outputs ...........................................................................................29

1.2 Digital Inputs..............................................................................................30

2 COUNTERS .....................................................................................................31

2.1 Reset mode..................................................................................................31

2.2 Normal mode..............................................................................................31

3 CONNECTIONS..............................................................................................32

3.1 Digital outputs............................................................................................33

3.2 Digital inputs..............................................................................................33

4 TECHNICAL

DATA (@ 25C +/-10C)............................................................35

4.1 Digital Outputs ...........................................................................................35

4.2 Digital Inputs..............................................................................................35

4.3 Auxiliary Power..........................................................................................36

INTAB Interface-Teknik AB

iv

OPTION : CONSTANT CURRENT SOURCES....................................................37

1 AN

OVERVIEW ..............................................................................................37

1.1 Temperature Measurements with Pt-100 Sensors ....................................38

2 DESCRIPTION................................................................................................39

3 CONNECTING SENSORS.............................................................................40

3.1 Screw Terminals.........................................................................................40

3.2 Measurement Methods...............................................................................41

4 TECHNICAL DATA.......................................................................................44

OPTION : MODEM PORT......................................................................................45

1 DATA FORMAT..............................................................................................45

2 CONNECTOR STANDARD...........................................................................45

3 ”3100I” MODEM SETTINGS ........................................................................46

4 C

OMPUTER MODEM SETTINGS.......................................................................47

INDEX.........................................................................................................................48

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BASIC UNIT

BASIC UNIT

1 AN OVERVIEW

1.1 General

The PC-logger model 3100i finds its use mostly in long term recording of
process signals and/or temperatures. Possible input ranges are +/-50mV,
+/-100mV, +/-1000mV, +/-10V, 20mA and thermoelectric voltages.
Very high resolution (25 000 steps or divisions) and excellent accuracy
(better than 400ppm) makes it possible to achieve remarkably good results
from the most difficult measuring task.
A 3100i together with software and a personal computer constitute a powerful
data acquisition/recording system. It is an excellent and up to date substitute
for strip chart recorders.

The rugged case lets you apply the ”3100i” in very harsh environments.
Noteworthy are the rubber edges that spare your table tops.

The scope of this manual is to enable the user to correctly connect transducers
and use the ”3100i” off-line.
How the ”3100i” is handled using our software and a PC is explained in the
program manuals and by the programs themselves by their user-friendly and
self-explanatory menus.

Those users who intend to write their own programs to collect data with the
”3100i” are recommended to study the special ”Command manual” that
describes available commands and their syntax.

In order to conserve battery capacity when the mains fail, the ”3100i” ”falls
asleep” when it hasn’t been called upon for about 2 minutes. It is woken by
incoming RS-232 serial data or by pressing the C key (see 2.).

Correct time is always supplied by our software.
On-line recordings are ”timed” by the computer.
Transferring off-line parameters will also supply correct time to the logger
RTC.
Check your computer clock, should the recording time information be
incorrect.

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INTAB Interface-Teknik AB

1.2 ”On-line” measurements

On-line measurements are performed with the ”3100i” connected to the
computer’s RS-232 port. Measurements can in this mode be monitored in real­time on the computer’s display. Incoming data are continuously transferred to
disk.

1.3 ”Off-line” measurements

Off-line recordings are only possible with units that are equipped with
“Display and 64k data memory” and optionally, “expansion memory”.
Off-line measurements should be preceded by the transferral of measurement
parameters from the computer to the ”3100i”.

These parameters contain, among others (see program manual), information
about time and date, measurement interval and which channels are to be
active.

These parameters are effective until a new set is downloaded. The ”3100i”
can, after downloading of the parameters, be disconnected from the computer
and started with the help of the keys next to the LCD (see 2.).
After all measurements are completed the ”3100i” is again connected to a
computer for transferral of collected data.

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2 DISPLAY AND KEYS

The LCD (Liquid Crystal Display) with adjacent keys are supplied with all
3100i:s that are equipped with internal memory.
This display and key combination is indispensable when making off-line
recordings. You indicate which function you want using the up/down arrows
and then confirm your choice with the OK-key.
The MULTIMETER is used to check transducer connections and function
before recording is started. You scroll up and down among the channels using
the up/down arrow keys. Automatic scrolling is started with the key under the
logo. A new channel is then shown every three seconds Try this feature by
pressing the ”intab°” logo.
RECORD is selected when you intend to collect data. Verify your choice with
”OK”. See illustration below.

Starting a new recording will delete the previous one.

Don’t forget to transfer data to the computer between recordings.

RECORD will also tell you ”Recording on”, if it is.
See Option: Modem Port for information on Modem Baudrate.

2.1 Clock

Logger time and date are shown in the display. They are set every time
recording parameters are supplied by the software. Correct time and date are
transferred from the computer together with off-line recording parameters.

The clock is only used by off-line recordings. Start time and sampling interval
(∆t) are used by the software to calculate data point time and date.

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3 STORAGE CAPACITY

The number of measurements that can be stored by the ”3100i” and/or
computer is dependent on the size and type of memory used.
The longest possible duration of a recording is a function of the number of
channels that are active, sampling rate and the size of the storage medium.

A discussion of how the maximum length of a recording can be calculated
from known parameters follows below.
It is assumed that recordings are made using software supplied by INTAB.

3.1 Storage capacity in your computer

The data storage capacity of your computer depends on the amount of free
space on the disk that is to store your measurements.

Modern computers usually have such large disks that the storage capacity is
enough for any recording task.

The only “problem” may be that it is too easy to over-sample, resulting in
cumbersome amounts of data.

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3.2 Storage capacity in the ”3100i”

The storage capacity of the ”3100i” is dependent on memory size.
Three sizes of memory can be supplied: 64k, 576k or 1088k.
Every value stored uses two bytes, making it easy to calculate available
recording time.
(Note that units without memory can only be used in on-line applications.)

An example: having 64k memory you want to measure four channels 10 times
every minute. The interval is then 6 seconds.
The formula will be: 6*64 000/2*4=48 000 seconds (or more than 13 hours).

The internal memory of the ”3100i” will only store one recording at a time.
Starting a new recording will erase the previous one. Recordings have to be
transferred to your computer before loading new parameters or starting new
measurements.

There is no limit to the number of times the same recording can be transferred
to the computer.
Measurement data will also not be lost if the internal batteries run down. A
backup lithium battery will retain data for more than 10 years.
Rotating (or endless) memory is described in the program manual.

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4 POWER SUPPLY

The ”3100i” is normally powered by the supplied mains adapter.

The ”3100i” is fitted with internal rechargeable batteries. They will give the
user at least two hours of measuring time without mains supply. The batteries
are trickle-charged when the mains adapter is connected.

There is no danger of overcharging the batteries. They should be left on
charge to keep them ready to use at all times. This will also prolong the
life of the batteries.

The internal accumulators may be disconnected from the rest of the circuitry
by removing a jumper on the analogue board.

< Jumper

Completely discharged batteries may at first take up to about 15 minutes to
charge to a point where the ”3100i” again will be operational. Two days of
charging should be enough to bring them up to full capacity.

Some applications require the ”3100i” to be powered by other sources.
Use a cable fitted with a TA3F (Switchcraft) connector to connect to, for
example, a car battery.
Don’t use sources supplying more than 15 Volts as this is the maximum
allowed.

When the mains fails or is disconnected, the ”3100i” will ”fall asleep” about
two minutes after the last command or keystroke has been entered. This
feature saves your rechargeable batteries for when they are needed.
Incoming serial (RS-232) commands or pressing the C-key will wake the
”3100i”.
Recordings will of course proceed uninterrupted. Long sampling intervals
(>10s) will allow the logger to fall asleep between samplings thus conserving
battery power.

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5 INPUTS - RANGES

All analogue channels are DIFFERENTIAL. They measure the voltage
between - and GND and the voltage between + and GND. The subtraction is
then performed internally.

NOTE
The GND is logger reference or signal ground. It has nothing in common with
other system or safety grounds unless the operator interconnects them.

When we in the following pages refer to GND or ground we only mean the
logger ground. NOTHING ELSE!

Standard inputs are balanced. This makes them very insensitive to noise if the
signal source is correctly connected. A signal cable consisting of a twisted pair
can be very long if the lowest potential of the source is connected to ground
via a separate cable.

The input ranges are set, adjusted and calibrated at factory prior to shipment.
Two main types of inputs are available: preset channels and ”Software Range
Switchable”.
Preset channel units are individually ”ranged”, adjusted and calibrated, and
cannot be altered by the user. They have to be returned to factory for
modification.
”3100i”:s with Software Range Switching has four programmable ranges per
channel. The range (or Full Scale Reading) of each channel is selected, or
programmed, together with the rest of the ”parameters” before the recording is
started.

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5.1 Preset ranges

The channels of ”3100i”:s are in groups of eight.
The channels in such a group may be individually set to one of the available
ranges.
Available ranges are +/-10V, +/-1000mV, +/-100mV, +/-50mV, 20mA and
thermo emf:s.

Temperature inputs measure thermoelectric voltages. These are then cold
junction compensated and linearized to present a correct value. All
temperature channels are presumed to have the same type of T/C connected.
”3100i” has, as standard, linearization tables for types B, E, J, K, R, S, T and
N.

All inputs (channels) have at least 25000 divisions. A division is the smallest
discernible change in input signal. The resolution of an input can be expressed
as FSR divided by the no. of divisions. Two examples:
a) A 10V input has a resolution of 10V/25000= ca 0.4mV.
b) A 50mV input has a resolution of 50mV/25000= ca 2µV.

5.2 Software Switchable Ranges

The ”3100i” can, as an option, be fitted with software switchable input ranges.
This versatile option can be compared to the switch on an ordinary multimeter
with the difference that the user has to press a number of keys on the computer
instead of the meter.
Channels are individually programmable. T/C linearization is individually
selectable so that channels may even have different types of thermocouples
connected.

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BASIC UNIT

5.3 Ranges and their Resolution

An ”3100i” is especially suited for monitoring process type signals and still
has the very sensitive 50mV range available.
The ranges and their resolutions are:

RANGE RESOLUTION
+/- 10V 0.4 mV
+/- 1000mV 40µV
+/- 100mV 4µV
+/- 50mV 2µV

An input set to the 50mV range can measure temperature with a resolution of

0.1°C using T/C:s type K. The temperature range will in this case be -100 to
+1200 °C.

Each channel has a shunt resistor that is connected across the input via a
switch on the analogue board adjacent to the screw terminals. This resistor has
to be switched in manually when current measurements are to be taken (see

6.3.2.).
Range here is 0 - 20mA which resolves the signal to 6µA.

Note that 4 - 20mA signals are beautifully transformed into correct magnitude
and unit by the ”transform” function of the software.

NOTE that the shunt resistor will overheat if subjected to more than
80mA.

5.4 Temperature measurements - T/C:s

The ”3100i” is specially adapted for temperature measuring using
thermocouples.
Thermocouples are active sensors that don’t require powering to supply a
signal. They are non-linear but are linearized by the ”3100i”.
A thermocouple is in its simplest form a pair of wires of dissimilar materials
that are soldered together at one end. The other end is connected to the two
screw terminals of a channel. The difference in temperature between the
soldered end and the screw terminals gives rise to a voltage that can be
measured.
This voltage is different for different thermocouple materials so tell the
software which type(s) you are using!

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INTAB Interface-Teknik AB

5.4.1 Ranges and linearization

Different types of thermocouples have differing levels of output. They
therefore have differing fields of application most often depending on the
temperature range to be measured.
What two materials make up the couple may also be of a certain importance.
We will however, have to assume that this is known to the user.
Below is a short summary of the properties of the most common types of
thermocouples. It is included to help in selecting type and range for your
application.
”K” is the most common type.

”Cold Junction” = 0°C

TYPE

mV at
200°C

mV at
600°C

mV at
1200°C

MAX temp °C
K 8.137 24.902 48.828 1370
N 5.912 20.609 43.836 1300
J 10.777 33.096 ---------- 760
T 9.286 --------- ---------- 400
S 1.440 5.237 11.947 1760
R 1.468 5.582 13.224 1760

Thermocouples are non-linear. This is corrected by the internal program of the
”3100i”.
Thermoelectric voltage is measured (in mV) and then adjusted for the cold
junction temperature according to the type specified. This adjusted voltage is
then used as input variable to a linearizing table. The table (one for each
thermocouple type) is constructed so that its contribution to the measurement
error is negligible.

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BASIC UNIT

5.4.2 Cold Junction Compensation

When using thermocouples to measure temperature it is almost always
necessary to know the temperature of the ”cold junction”. Thermoelectric
voltage has to be ”adjusted” with respect to this temperature.
Thermoelectric voltage is the result of the temperature difference between
the cold junction and the hot junction.
A solid state temperature sensor has been placed centrally in the screw
terminal area of the analogue board. Its temperature is automatically sampled
every time a temperature measurement is taken. All temperature
measurements are thus compensated for the actual temperature of the
terminals themselves.

Some precautions have to be taken if the ”3100i” is exposed to rapid
temperature gradients. Since temperature is measured in one point only, a
gradient from one side of the unit to the other may cause misreadings.

By giving the unit time to reach a stable temperature before recordings are
started and by protecting it from sudden changes of ambient temperature a
very high degree of accuracy can be achieved.

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6 CONNECTORS

6.1 Power

Power is applied through a TA3F (Switchcraft) female connector connected as
follows :
Pin 1 : + 12-15VDC
2 : 0V
3 : + 20-28VDC (this is an alternative to pin 1)

6.2 Computer

”3100i” connects to a serial port of the computer using the supplied spiral
cable.
The 15 pin D-SUB connector has the following pin-outs:

pin 2 : Tx
pin 3 : Rx
pin 5 : CTS
pin 6 : DTR
pin 7 : GND

Leave the rest of the pins unconnected or damage may result!!

Typical Computer to ”3100i” cables:

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6.3 Connecting Sensors and Transducers

Sensors or Transducers are connected to the screw terminals that are
accessible under the lid.
The terminals are detachable and can be tilted 90°. Terminal assignment and
polarity can be seen in the figure below.
Use the 16 hole bracket as strain-relief for transducer cables. You can use a
tie-wrap or simply thread the wire trough two holes.

21

22

23

24

13

14

15

16

DIFF GND

5

6

7

8

DIFF GNDDIFF GND

+

-

-

CHANNEL 7

CHANNEL 8

­+

-

CHANNEL 15

CHANNEL 16

+

-

-

CHANNEL 23

CHANNEL 24

U I

13

14

15

16

U I

12

10

11

U I

21

22

23

24

9

+

-

+

-

+

CHANNEL 21

CHANNEL 22

+

­+

­+

CHANNEL 13

CHANNEL 14

+

-

+

-

+

CHANNEL 5

CHANNEL 6

GND GND

U I

17

18

19

20

+

-

-

CHANNEL 20

­+

-

CHANNEL 12

+

-

-

CHANNEL 4

+

-

+

-

CHANNEL 1

CHANNEL 2

CHANNEL 3

+

-

+

-

CHANNEL 9

CHANNEL 10

CHANNEL 11

+

-

+

-

CHANNEL 17

CHANNEL 18

CHANNEL 19

U I

8
7
6
5

4
3

U I

17

18

19

20

2
1

+

9

10

11

12

DIFF GND

+

1

2

3

4

DIFF GND

+

DIFF GND

Switches for choice
between single ended
(GND) or differential
inputs

Software Range­Switchable units have
these switches.

In position ”I” they
connect a shunt
resistor across the
input for current
measurements.

Note the irregular
numbering of the
switches.

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Connecting Sensors and Transducers (cont.)

The following information also applies to units fitted with jack panels.
The panel is only an extension of the screw terminals. GND is also made
available through two black banana jacks at the logger end.

There are a few basic rules that have to be followed when connecting sensors
and transducers.
Let us first take a look at a block diagram of the inputs. They are differential
and, as can be seen, have no internal connection to signal ground.

Input block diagram

Differential channels measure (as the name implies) the difference in voltage
between the + and - input in relation to signal ground.

Another way of saying this is that each channel measures TWO voltages:

- a) between GND and minus and

- b) between GND and plus.

- The difference is then calculated internally and presented as the channel
value.

By ”GROUND” we mean the internal signal ground of the ”3100i”. It has
nothing to do with safety or system ground of other systems unless you
interconnect them.
Also note that the ”3100i” analogue ground is the same electrical point as
the RS-232 signal return AND the 0V of the power supply input
connector.

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Connecting Sensors and Transducers (cont.).

The impedance between the positive and negative inputs to ground is of the
order of several MΩ. They must therefore never be allowed to float outside
the specified common mode range, but must be referenced to ground in some
way.
Use the miniature switches to set up the channels as single ended inputs.
These switches ground the negative input of corresponding channels.
Before doing this, you have to make sure that no potential exists between the
negative outputs of your transducers as his could burn out your wiring or
worse.
You must also be careful not to introduce ground loops in your signal paths.

To maintain the validity of your measurements you have to take the common
mode range into account.
Common mode range is +/-10V for most ranges.

LOGGED
SIGNAL

+

-

CHANNEL

GND (ref)

MAX 10V

COMMON MODE SIGNAL

AAC-2 : "COMMON MODE"

The inputs will not be damaged by voltages above this as long as they are
within 30V off signal ground.
The following sections of this manual will provide some examples of how
transducers can be connected.

NOTE that these instructions also are valid for units with jack panels. You
have to open the lid to make those channels single ended that should be single
ended.
”3100i” signal ground is here also available as two black banana jacks on one
of the sides of the casing.

The jack panel must be looked upon as a device external to the logger itself. It
is built into the logger casing only for practical reasons.

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6.3.1 Thermocouples

Thermocouples can be connected in two ways (see fig. below). Which one you
choose will depend on your particular application. As a general rule it would
appear to be more practical to connect the negative input to ground by setting
the switch in the single-ended position. Never leave any transducers without
some type of connection to ground.

The two methods can be combined but you have to make sure that your
ground leads don’t carry any current or connect to the same point from two
directions. Ground leads that carry current will, at best, ruin your
measurements. At worst it will burn out your wiring.
Avoid these problems by using a one-point grounding scheme.

1) T/C ”hot” junction in contact with conducting object.

+

­+

-

DIFF

1

2

GND

Connect object to signal
GND

Connect your T/C:s

Place switch in position
”DIFF”

2) T/C ”hot” junction isolated from measured object.

+

­+

-

1

2

GNDDIFF

Do NOT connect object
to signal GND

Connect your T/C:s

Place switch in position
”GND” making them
single ended

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6.3.2 Current Loops

Current loops are usually process type signals (0 - 20mA).
The transmitters that output this type of signal are usually ”floating” and don’t
present any problem in so far as grounding is concerned. Problems can,
however, arise because other equipment that receives this signal may or may
not be grounded.

Care must also be taken so that other equipment don’t introduce common
modes outside the permitted range. Least problems should arise if the ”3100i”
is inserted as near the most negative end of the loop as possible.

1) ”Grounded” current loops.

0-20mA

ANDRA INSTRUMENT

+

­+

-

1

2

GNDDIFF

0-20mA

Connect ”3100i” signal
GND to system
ground.

Connect your loops

Place switch in
position ”DIFF”

2) “Floating” current loops.

0-20mA

0-20mA

+

­+

-

1

2

GNDDIFF

Leave signal GND
unconnected.

Connect your loops

Refer loops to signal
GND by placing
switch in position
”GND”

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6.3.3 Voltages

Voltages are measured by connecting in one of the two indicated ways (see
figure below). The two methods can be combined if care is taken to avoid
ground loops.

1) Signals with Common ground reference.

+

­+

-

1

2

GNDDIFF

Connect ”3100i” signal
GND to system ground.

Connect sensors

Place switch in position
”DIFF”

2) ”Floating” signals.

+

­+

-

1

2

DIFF GND

Leave signal GND
unconnected.

Connect your sensors

Refer signals to GND by
placing switch in position
”GND”

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7 MISCELLANEOUS

As is implied by the topic, this section is intended for information that is not
readily covered by the other sections of this manual. The information is,
however, considered important or interesting enough to be included.

7.1 Reset

A master reset of the ”3100i” can be performed by temporarily shorting pins 7
and 8 of the 15 pin D-SUB connector. A master reset will erase the internal
program of the ”3100i”.
You will then have to re-boot the program from your computer. Rebooting is
done from Intab PC-logger software. Please consult your software manual for
details.
Bootable files have the extension .LDM. The Intab PC-logger software
automatically selects the correct one if there are several present on the disk.

Front view of the D-SUB connector

7.2 Program

The program that controls the ”3100i” is stored in Random Access Memories
in the ”3100i” itself. This makes it possible to modify the way the ”3100i”
operates by simply downloading (or booting) a new controller program (see

7.1).

Bootable files reside on the same directory as your Intab PC-logger software.
They are recognised by the .LDM extension. These Load Modules are
different for different models of loggers. Your Intab logger software will
always select the one appropriate for your logger.

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8 TECHNICAL SPECIFICATIONS

8.1 Analog Data

8.1.1 Method

Σ-∆ converter

8.1.2 Measurement interval

Programmable in 1s steps - min 1s
N.B. : All channels are measured within the same second

8.1.3 Time Base

X-tal reference
Uncertainty 20ppm at 20°C
Stability 50ppm (-20°C to +60°C)

8.1.4 Inputs

8,16 or 24 differential inputs.
Impedance:
Overvoltage protection:

Min 400 kΩ.
30V continuous.
Higher voltages may damage the inputs

N.B.: current inputs are shunted by 51Ω

8.1.5 Ranges

Preset: 0-20mA, +/-10V, +/-1000mV, +/-100mV or +/-50 mV

Temperatures: 50mV thermo emf
Thermoelectric voltages are linearized and cold junction
compensated

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Switchable:

Four Voltage Ranges per Channel
+/- 10V
+/- 1000mV
+/- 100mV
+/- 50 mV

One Current Range
0 - 20 mA
Each channel has a switchable 51Ω shunt for the 20mA range.
It is connected across the input by using the on-board switch
(see 5.2).

NOTE: Max. allowed current through shunt is 80mA

8.1.6 Divisions

Min 25000 divisions

8.1.7 Resolution

(Examples)

Range Resolution (approx.)
10V 0.4mV
1000mV

40µV

100mV

4µV

50mV

2µV

20mA 800nA

Thermoelectric voltage, 50mV FSR: (Examples)
Thermocouple J :
Thermocouple K :
Thermocouple T :
Thermocouple S :
Thermocouple E :

0.1°C

0.1°C

0.1°C

0.3°C

0.1°C

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8.1.8 Uncertainty

(at 23°C +/-5°C)

Ranges (ppm of reading + divs.)

Voltage 10V : +/-(100ppm+2divs.)
1000mV : +/-(200ppm+2divs.)
100mV : +/-(300ppm+2divs.)
50mV : +/-(400ppm+2divs.)
Current 20mA : +/-(300ppm+2divs.)
Noise +/-1 bit
Temp. co. 50ppm/°C
T/C linearization
error

+/-0.1°C

Cold Junction +/-0.5°C

8.1.9 Common Mode

Common mode range:

CMR

: min +/-5V at 10V FSR
: min +/-10V other ranges
: min 80dB

8.2 Storage Memory

Sizes : 0k Bytes (only for on-line recordings)
64k Bytes (optional)
64k +512k Bytes (optional)
64k + 1024k Bytes (optional)

8.3 Computer communication

Data is transferred in a serial form to and from the computer.
The serial standard conforms to a subset of RS-232.
Format: 8 bit ASCII
1 start bit
8 data bits
1 stop bit
19200 baud

8.4 Commands

See “Command Manual”

27

BASIC UNIT

8.5 Power

Voltage:
Operating current:
Charging current:

12 - 15 VDC
Max 400 mA (charging + operating)
Max 200 mA (initial)
Max 60 mA (trickle)

8.5.1 Rechargeable Batteries

Charging time: Min 40 hours with supplied mains adapter.
Should be continuously (trickle-)charged.
Capacity: Min 2 hours of operation with fully charged
accumulators

8.5.2 Charger/Mains Adapter

Voltage: 12 - 15VDC
Current: Min 500 mA

8.6 Mechanical specifications

Width: 165mm
Length: 315mm
Height: 62 or 88mm (depending on model)
Weigh: 1.7 - 2.5kg (depending on model)

8.7 Environmental conditions

Min operating temp -20°C
Max operating temp +50°C
Min storage temp -30°C
Max storage temp +55°C

Max rel. humidity 80% non-condensing

28

INTAB Interface-Teknik AB

29

OPTION: Digital I/O and Pulse Counters

OPTION: Digital I/O and Pulse Counters

1 AN OVERVIEW

The ”3100i” can, in addition to the analogue inputs, be fitted with a digital
I/O-interface.
This digital board is mainly used in event-counting applications but can also
be used where status or on/off signals must be detected.
INTAB PC-logger software support the use of the relay outputs as alarms.

This card is available in two versions: with or without counters.

A fully equipped card has the following I/O’s:

- 4 digital outputs (relays)

- 8 digital inputs, 6 of which are used as inputs to the counters.

1.1 Digital Outputs

Four digital outputs in the form of (relay) contact closures are available. They
find their use as alarms and in simple regulating functions and are as such
supported by the EasyView Pro software.

The relay coils are, to prolong battery life, powered directly by the mains
adapter and not by the internal batteries.

The EasyView Pro PC-logger software supports programming of alarm levels
that can be assigned to these relays.

Digital output status is reflected in channel 32.
The binary sum of active outputs are presented with DO1 as LSB.

30

INTAB Interface-Teknik AB

1.2 Digital Inputs

Eight digital inputs are available. Input status of these can be monitored by the
computer.
This way you can measure temperature and at the same time make sure that
control signals assume the correct level at the right time.

Six event counters can be paralleled with these inputs.
By connecting pulse type transducers (flowmeters are often of this type) to
these inputs you will get values that represent pulses/time interval. This is the
easily transformed into litres per second.
The ”3100i” software can be said to be treating these values as if they were
ordinary analogue values or voltages.

The digital inputs are on request fitted with filters for electrically noisy
environments.

Digital input status is reflected in channel 31.
The binary sum of active inputs are presented with DI1 as LSB.

1.2.1 Opto isolated inputs

The Opto isolated inputs (DI1 - DI8) are used to detect high-level (>10V)
signals or where isolation is essential.

The a and b inputs are equivalent and insensitive to reversal of polarity.

The auxiliary output (VO) will power the opto-couplers if no external source
is available. This output is connected directly to the mains adapter. Make sure
you have connected it if you want to use this output.
Remember also that you lose isolation when you use VO.

1.2.2 TTL-compatible inputs.

TTL- or low-level signals are connected to the so called pulse inputs (P1-P6).
These are paralleled with the corresponding DO inputs and do not provide any
isolation to the measured/monitored object.
The auxiliary power output for these inputs is Vp.
This voltage is derived from the internal battery through a current limiting
resistor

31

OPTION: Digital I/O and Pulse Counters

2 COUNTERS

The digital I/O card can be fitted with six sixteen bit counters. Each of these
counts up to 65535 and then wraps around to zero.
They can be read with constant time intervals resulting in measurements
values representing pulses per delta-t.

Flowmeters output a set number of pulses per given unit of volume. They are
therefore an excellent example of how the counters can be used to measure
flow.

Counter values are presented in channels 25 through 30

2.1 Reset mode

Reset mode will reset (or zero) the counters as soon as their values are taken
care of. These values are then treated as if they were ordinary analogue
measurements. (Litres/second maybe?)

2.2 Normal mode

Normal (or accumulating) mode does not reset the counters when they have
been read. Values that are taken with this mode could be said to represent the
time-integral of the transducer output.

32

INTAB Interface-Teknik AB

3 CONNECTIONS

Connections are made to the screw terminals under the lid of the ”3100i”.
Note that Vo is un-fused and should not be loaded by more than the mains
adapter is able to supply and never more than 500mA.

Terminal configuration is shown in the illustration below.

DI 8b

DI 8a

DO 4b

DO 4a

DO 3b

DO 3a

DO 2b

DO 2a

DI 7b

DI 7a

DI 6b

DI 6a

DI 5b

DI 5a

DO 1b

DO 1a

GND

GND

P6

P5

VO

GND

DI 4b

DI 4a

DI 2b

DI 2a

DI 3b

DI 3a

P2

P1

P4

P3

Vp

Vp

DI 1b

DI 1a

DO = Digital Output
DI = Digital Input
P = Pulse Input
Vo = Auxiliary Power (for DI)
Vp = Auxiliary Power (for P)

33

OPTION: Digital I/O and Pulse Counters

3.1 Digital outputs

The digital outputs are in the form of four normally open relays.
These potential free contacts are accessible on DO1a,b - DO4a,b; see figure.

DIGITAL OUTPUTS

RELAY SPST

DO a

DO b

Switching Capability:
Power - 30W/50VA
Voltage - 45V AC/DC
Current - 1.25A AC/DC

N.B. No voltage above 45V may be
applied to any part of the logger.

3.2 Digital inputs

The figure below shows how the opto-isolated and TTL inputs are
interconnected.

FILTER

OPTO
ISOL.

RECTI­FIER

DI a

DI b

Px

FILTER

1
2

3

34

INTAB Interface-Teknik AB

3.2.1 Opto Isolated

The opto-isolated inputs can be used in two ways. Which method you use
depends on your particular application.
See figure!
The transducer marked ”PULSE” has to be able to drive the input:
see 4.2.1 for levels and frequencies.
Remember that mechanical contacts always bounce when brought together.
This bouncing will, unless filtered, result in a burst rather than one pulse.

VO

GND

OR

DI b

DI a

PULSE

MAX 24V

OPTO ISOLATION
ANY POLARITY

DI a

DI b

3.2.2 TTL Compatible

The TTL-compatible inputs (P = Pulse in) are connected as in the figure.
Note that signal ground (GND) of the digital card has to be connected to
signal ground of the system or transducer that is used with these inputs.

1 2

TTL/CMOS

AND/OR

GND

GND

P2

P1

Vp

Vp

35

OPTION: Digital I/O and Pulse Counters

4 TECHNICAL DATA (@ 25°C +/-10°C)

4.1 Digital Outputs

No of outputs : 4
Type : Potential-free relay contacts (NO, SPST)
Switching capability :
Power

Voltage
Current
Max. operating current

: 30W/50VA
: 45V AC/DC
: 1.25A AC/DC
: 1A @ 60°C

4.2 Digital Inputs

4.2.1 Opto-Isolated Inputs

No of inputs
”Low” level
”High” level
Max input voltage
Impedance
Input current
Max frequency

: 8
: Max 4V
: Min 8V
: 30V
: Min 1k Ohms
: Max 30mA at 30V in
: Min 30kHz at duty cycle50%

4.2.2 TTL-compatible inputs

No of inputs
”Low” level
”High” level
Max input voltage
Impedance
Input current
Max frequency

Min pulse width

: 6
: Max 1.5V
: Min 3.5V
: 20V
: Min 50k Ohms
: Max 30mA at 30V in
: Min 70kHz at 5V and duty cycle=50%
: Min 30kHz at 10V and duty cycle=50%
: Min 20kHz at 15V and duty cycle=50%
: Max 15µs

36

INTAB Interface-Teknik AB

4.3 Auxiliary Power

4.3.1 for Opto-Couplers

Voltage : mains adapter output, max 15V.
Current : mains adapter rating -300mA or max 200mA

4.3.2 for TTL-Inputs

Voltage : 4-6V
Impedance : 1kΩ

OPTION : Constant Current Sources

37

OPTION : Constant Current Sources

1 AN OVERVIEW

Constant Current Sources have their natural use when measuring resistance.
A resistor is in itself passive and does not lend itself to be measured unless
special arrangements are made. It has to be tricked into revealing its value as a
voltage that can be measured and logged.
This voltage has to be proportional to the resistance.

An excursion in time, back to the old school days, may make you remember
”Ohm’s Law”. It states that U=R*I. I.e. ”the voltage across a resistor is the
product of the current through it and its resistance”.
Juggle the letters a bit and you get R=U/I (School maths again).
As current (I) is known and constant it is easily seen that measured voltage is
directly proportional to resistance.

The constant current is almost always set to 0.500mA. I.e. every measured mV
corresponds to 2Ω. Insert these values into the formula above and you get:
1mV/0.500mA=
10-3/0.5*10-3 (V/A)=
1/0.5 (V/A) =2Ω (V/A=Ω)! QED

Below is a schematic diagram of how a constant current source can be put to
work.

R

I

+

U=R*I

-

This method is called ”four-wire resistance measurement”.
How to do the practical wiring is shown in a later section in this manual.

INTAB Interface-Teknik AB

38

1.1 Temperature Measurements with Pt-100 Sensors

A Pt-100 is a resistance temperature sensor or RTD (Resistance Temperature
Detector). Its resistance changes with temperature. By measuring resistance
using the four-wire technique described above, it is easily converted to
temperature. The conversion can be either a linear transform (y=kx+l) or for
more accurate conversions a polynomial.

One linear transformation can be defined as the line that passes through 0°C at
100Ω and f. ex. 266,4°C at 200Ω. In other words: 50mV corresponds to 0°C and
100mV corresponds to 266.4°C
(I=0.5mA)

If you want to transform resistance into temperature you can of course use this
equation: Rt=Ro(1+At+Bt2)
where Ro ~ 100
A ~ 3.9083 x 10-3
B ~ -4.183 x 10-7

Concerning accuracy of the ”3100i” when performing Pt-100
measurements, the following should be noted:

In four-wire techniques total uncertainty is the sum of ”3100i” analog channel
uncertainty and constant current uncertainty. The analog inputs have an
uncertainty of +/- 300ppm. Using the 100mV range and reading 50mV, this
translates to about 15µV. The constant current sources have an uncertainty of +/-

0.5 µA. At a resistance of 100Ω this corresponds to 100Ω * 0.5 µA = 0.050 mV.

A Pt-100 sensor changes its resistance from 100.0Ω to 100.39Ω as a result of a
temperature change from 0°C to 1°C.
As the constant current is 0.5mA this corresponds to:

0.39Ω * 0.5mA = 0.195mV. Therefore:

• uncertainty due to input is 0.015/0.195 = 0.08°C.

• uncertainty due to constant current is 0.050 / 0.195 = 0.26°C.

Total uncertainty can therefore, if you are unlucky, add up to 0.34°C. ( ”3100i”
@ 25°C +/- 10°C)

Don’t forget that Pt-100 sensors by no means are perfect.
A class B Pt-100 has an uncertainty of +/-0.8°C at 100°C and
a class A Pt-100 has an uncertainty of +/-0.35°C at 100°C.
These possible errors have to be added to the ”3100i” uncertainty to get a
reliable estimate of total system uncertainty.

OPTION : Constant Current Sources

39

2 DESCRIPTION

Each constant current sources board may have 8, 16 or 24 constant current
outputs.

Every group of 8 sources is really only one source that is multiplexed in turn to
the eight outputs.

This means that the constant current is not flowing all the time. It is only present
and constant during the time its associated channel is being sampled.

Each channel takes between 80ms and 100ms to sample. The maximum time the
constant current is flowing is actually only this long. Therefore it never
contributes to any self-heating of the sensor.

What are the implications of what we have just said? well!
Channels are sampled one by one within an 8-group.
As channel one is sampled there is a constant current coming out of source #1.
As channel two is sampled there is a constant current coming out of source #2.
And so on.

Note that channel groups 9-16 and 17-24 are ”in step” with the first group. I.e.
channel 9 and channel 17 are sampled concurrently with channel number one.

INTAB Interface-Teknik AB

40

3 CONNECTING SENSORS

3.1 Screw Terminals

The screw terminals for the current sources are placed symmetrically with
respect to corresponding analogue channels. They are therefore easily and
logically connected to sensors.

+

-

-

8

­+

-

16

+

-

-

24

+

-

+

-

+

21

22

23

+

­+

­+

13

14

15

+

-

+

-

+

5

6

7

+

-

-

20

­+

-

12

+

-

-

4

+

-

+

-

2

3

+

-

+

-

10

11

+

-

+

-

18

19

+

17

+

9

+

1

The constant current comes out of the ”+”-terminal whenever the corresponding
channel is sampled.
It should pass through the sensor resistance and return to the ”-”-terminal. This
minus terminal is in actual fact the ”3100i” reference ground or as it is usually
called: GND.

The Diff/Gnd switch should be in the Diff position !!!! (Hopefully you had
realised this already.)

OPTION : Constant Current Sources

41

3.2 Measurement Methods

There are several ways of connecting, and measuring the value of, resistive
components. Here follow a few:

The four-wire resistance measurement method is the most straight forward and
accurate method.

The five-wire method also has its place in some applications.

A three-wire version of the five-wire method can also be employed where the
demand for accuracy is small.

Three-wire resistance measuring where the three-wire device is part of a
Wheatstone bridge is also common. The resistance to be measured is one of the
four resistances of the bridge. Should this method be preferred, the user can
easily calculate the other three legs of the bridge. For more information please
consult applicable school literature on this subject.

INTAB Interface-Teknik AB

42

3.2.1 Four-Wire Resistance Measurements (Pt-100)

The theory behind this method is explained earlier in this manual.

Below is a schematic diagram of how to connect two Pt-100 sensors. It can of
course be expanded to up to 24 sensors.
You realise, of course, that these can be combined with other sensors and
transducers that don’t require current sources.

Analogue board ⇓ ⇓ Constant Current Sources

++

­+

­+

-

+

-

+

-

-

Pt100

Pt100

+

­+

+

­+

With this method all sensors are referenced to ”3100i” signal ground via the
constant current return ( - ). The Diff/Gnd switch must consequently be in the
Diff position ( right? ).

OPTION : Constant Current Sources

43

3.2.2 Five-Wire Resistance Measurements

This method is used when there is a requirement for a wider range than is
possible using the four-wire technique when measuring temperature with an
RTD (Pt-100).
By using the "differentiality" of the analogue channels a base level resistance
(like 100Ω of the Pt-100 at 0°C) can be subtracted.
This is how to do it shown in schematic form:

0.500mA

Constant Current

0.500mA

Constant Current

I

I

R1

(Pt-100)

R2

(100)

-

+

U=R1*I-R2*I

GND

2I

AAC-2

The plus input of the channel measures the voltage developed across the
temperature sensor (R1).
The minus input measures the voltage developed by a similar current source
across a reference resistor (R2).
The lead return resistance is with this method elegantly compensated for as it is
included in both the minus and plus signal and thus subtracted from the sensor
measurement.
How to calculate temperature from resultant voltages using different values for
R2 is common high school mathematics and is left to the operator. We
recommend the use of Pt-100 tables however.
Apply the best fit straight line (equation) transform to the temperature range that
is to be recorded. This will give best and most accurate readings. A very good
accuracy can be achieved if the constant current sources and the reference
resistor are calibrated.

NOTE also that the two current sources needed for each sensor must be ”in
step”. Use for example the pairs 1 and 9, or 2 and 10, or 3 and 11, and so on.

INTAB Interface-Teknik AB

44

3.2.3 Three-Wire Resistance Measurements

This method is a poor version of the five-wire method. Its only excuse is that it
only needs three wires to the sensor. (It must not be mistaken for the three-wire
bridge method that is not dealt with in this manual). This method requires the
lead resistances to be either compensated for by calibration or unimportant
enough to be disregarded. They will otherwise contribute to a considerable
measurement error.

This is how you go about connecting the three wires. Compare this to the five
wire method!

0.500mA

Constant Current

0.500mA

Constant Current

I

R1

(Pt-100)

-

+

U=R1*I-R2*I

GND

R2

(100)

AAC-2

Use ordinary high school maths and Pt-100 tables to convert measured voltage
into temperature. Apply the best fit straight line (equation) transform to the
temperature range that is to be recorded. This will give best and most accurate
readings.

4 TECHNICAL DATA

At 25°C and nominal current 500µA (other ranges on request)

Constant Current

500µA

Accuracy

+/-0.5µA

Compliance

2.5V (0≤RL≤5kΩ)

Tempco (max) +/-150ppm/°C

OPTION : Modem Port

45

OPTION : Modem Port

”3100i”:s may on demand be fitted with a modem port. This serial port is
specially adapted to modems.

1 DATA FORMAT

The serial data format between the ”3100i” and a modem is:
1 Start Bit
8 Data Bits
1 Stop Bit
No Parity

2 CONNECTOR STANDARD

The connections adhere to a subset of the RS-232C standard.
The connector is 25 pole D-sub connected as a DTE connector.
The following pins and signals are used:

2) Tx

3) Rx

4) DTR

5) CTS

7) Signal Return

8) DCD

20) DTR

22) RI

INTAB Interface-Teknik AB

46

3 ”3100i” MODEM SETTINGS

Press the up or down arrow by the ”3100i” display until you see the ”MODEM
BAUDRATE” menu. See basic unit manual chapter 2 !
Press OK to see the menu ”SET BAUDRATE”. Select desired baud rate using
up or down arrow and end off by OK:ing. The menu should indicate selected
baud rate under the caption ”MODEM BAUDRATE”.

There are four commands that set up the ”3100i” for modem control. See also
the ”Command Manual”.
The command INITANSWER supplies the string that initialises the modem as
the first ring signal arrives.
ANSWER will supply the string to be sent to the modem to make it answer the
call. DIAL” supplies the commands that are to be performed at an alarm
situation.
RING is a command that programs how many rings that must arrive before the
call is answered.
The commands have the following default settings (BPA_0226.LDM or later):

INITANSWER
ANSWER
RING
DIAL

ATE0!
ATA!
3
Has no initial settings.
Can be : ATZ!£ATE0!ATDT123456789!
Consult the Command Manual for more information

To set these parameters the ”3100i” has to be connected to the computer serial
port and some type of terminal software running.
The following commands are examples and may or may not suit your modem:

INITANSWER:”ATZ!£ATE0!£ATW2S95=2!”
ANSWER:”ATA!”

”3100i” responds with OK
”3100i” responds with OK

Settings can be checked by typing:

INITANSWER:?
ANSWER:?

”3100i” responds with ”ATZ!£ATE0!£AT&C0!”
”3100i” responds with ”AT&C1!£ATA!”

The exclamation mark ”!” and pound sign ”£” have special functions:
! :There is no normal way to include the [Enter] character in a string. The !

replaces it.
£ : Some MODEMS are not able to receive multiple commands without a
break in between. The £ introduces a 2 second pause.

OPTION : Modem Port

47

4 Computer MODEM settings

It is not always a trivial task to get modem communications to work. There are
several parameters that have to be correctly set up. MODEMS do not necessarily
have to be of the same type but it usually helps.

MODEMS of your choice have to be set up to report DCE line speed and error
correction method. (xxx = arbitrary letters)
The following two types of messages are accepted:

• CONNECT 14400 No error correction

• CONNECT 14400/xxx Error correction

The highest speed with which the modems are able to operate is the RS-232
baud rate. Computer baud rate is set in the MODEM.INM file

If the logger modem answers CONNECT 14400/ARQ, the computer modem has
to reply with an identical string. (And vice versa).

INTAB Interface-Teknik AB

48

INDEX

A

accumulating · 31
alarm levels · 29
alarms · 29
ANSWER · 46
available ranges · 12

B

B · 12
backup · 9
balanced · 11
Boot · 23
bounce · 34
burn out · 20

C

clock · 5
Clock · 7
CMR · 26
cold junction · 15
cold junction temperature · 14
Common mode · 19
Compliance · 44
computer · 16
computer clock · 5
Constant Current · 44
Constant Current Sources · 37
controller program · 23
Correct time · 5
counters · 29, 31
Current loops · 21
current measurements · 13, 17

D

date · 7
detachable · 17
DIAL · 46
DIFF · 21, 22

differential · 18
DIFFERENTIAL · 11

digital I/O · 29
digital inputs · 30
digital outputs · 33
division · 12
downloading · 6
D-SUB · 16
DTE connector · 45
duration · 8

E

E · 12

endless · 9
erase · 23
error correction · 47
event-counting · 29

F

fall asleep · 10
five-wire · 41
flow · 31

four-wire · 41
four-wire resistance measurement · 37

G

GND · 11, 18, 21, 22
gradient · 15
ground · 20
GROUND · 18
ground loops · 22

H

hard disk · 8
HD disk · 8
hot junction · 15

I

impedance · 19
Impedance · 24
internal memory · 9

J

J · 12, 14
jack panels · 18, 19

K

K · 12, 13, 14
keys · 7

L

LCD · 7
LDM · 23
linear transform · 38
linearization tables · 12
linearized · 13
Load Modules · 23

M

mains adapter · 10
mains fails · 10

INDEX

49

master reset · 23
miniature switches · 19
misreadings · 15
MODEM BAUDRATE · 46
modem control · 46
modem port · 45
multimeter · 12
MULTIMETER · 7

N

N · 12, 14
Normal mode · 31

O

Off-line · 6
Ohm’s Law · 37
OK · 7
On-line · 6
Opto isolated inputs · 30
opto-isolated · 33, 34
overheat · 13
Overvoltage protection · 24

P

P · 34
pinouts · 16
Power · 16
preset channels · 11
process · 13
programmable · 12
Pt-100 · 38
PULSE · 34
pulse inputs · 30

R

R · 12, 14
ranges · 12
Rebooting · 23
rechargeable batteries · 10
RECORD · 7
recording time · 9
relay coils · 29
relay outputs · 29
Reset mode · 31
resistance · 37
resolution · 13
retain data · 9

RING · 46
RS-232 · 26
RTC · 5
RTD · 38

S

S · 12, 14
screw terminal · 15
screw terminals · 17
self-heating · 39
shunt resistor · 13, 17
single ended · 17, 20
single-ended · 20
Software Range Switchable · 11
storage capacity · 8, 9
strain-relief · 17
system ground · 18
system uncertainty · 38

T

T · 12, 14
T/C:s · 20
temperature · 13
temperature sensor · 15
Terminal configuration · 31
thermo emf · 12
thermocouples · 13, 14
Thermoelectric voltage · 15
three-wire · 41
time · 5
time and date · 7
transfer · 9
transferral · 6
trickle-charge · 10
TTL · 33
TTL-compatible · 34

U

U=R*I · 37
uncertainty · 38

W

wake the ”3100i” · 10
Vo · 31
Voltages · 22