Omega Products OM-SC User Manual

⻬ Measures and Records

DC Current, DC
Voltage Temperature,
Contact Closure and
Ambient Light

⻬ Time Extension

Recording—Automatic
Sampling up to 1 Year

⻬ Automatic

Scaling Provides for
Best Resolution

⻬ Easy-to-Use

Windows

®

Software

Portable Low Cost Datalogger

Part of the NOMAD®Family

Whether the OM-SC datalogger
records for an hour, a week or a year,
by using its innovative time extension
recording technique, the completed
recording is at a sampling interval
that is appropriate for the length of
the recording session. Initially the
datalogger samples every 0.88
seconds. In 2 hours, its memory is
full. It then doubles its sampling
interval and continues recording.
After 4 hours, its memory is full again
using a sampling interval of 1.76
seconds. Each time its memory fills
up, the OM-SC doubles its sampling
interval and repeats the process.
Refer to the table above for a list of
sampling intervals corresponding to
various lengths of recording sessions.

The OM-SC records temperature with

its internal thermistor temperature
sensor or with an optional external
temperature sensor. The datalogger
also measures DC voltage, DC
current (the OM-SC datalogger can
be used to record 4 to 20 mA current
loop signals and then to scale, plot,
print, totalize and save the data in the
process units being measured) and
contact status. It is not necessary to
specify the recording function in
advance; you specify it when
downloading to your computer.

Automatic scaling permits the
OM-SC to operate over wide ranges
of DC voltage and DC current signal
levels. The datalogger starts
recording at its lowest scale range
and rescales each time the signal
exceeds the scale range. Automatic
scaling also functions when the
OM-SC is recording temperature;
it allows the datalogger’s 256 steps of
resolution to be used to maximum
advantage. When recording
temperature, the scale range
is determined by the maximum
temperature recorded, and the
resolution is best at the top of the
range. The OM-SC initially scales
itself on its first reading and is limited
to four scale changes after that.

The OM-SC software produces a
clear, well-formatted presentation
quality graph. The vertical grid lines
fall on major time increments. A zoom

function permits the user to examine
details in the record and select a
portion of the graph for display. The
graph includes the datalogger’s serial
number, complete date and time
information, title provided by the user,
sample rate, min/max and average
signal readings, and the online signal
reading. The finished graph can be
printed or exported to other software.
The data can be saved to disk and
imported into common spreadsheet
programs.

The operation of the datalogger is
controlled by a button on the front of
the unit. The mode of operation is
indicated by a light to the left of the
button. There are three modes of
operation: RECORD, STANDBY, and
SLEEP. RECORD is entered from
SLEEP by a press of the button; the
light makes double blinks to indicate
that the datalogger is recording.
STANDBY is entered from RECORD
by a press of the button; it is indicated
by single blinks on the light. In the
STANDBY mode the datalogger does
not record; it keeps time and retains
data for later downloading to the
computer. SLEEP is entered from
RECORD or STANDBY by a long (2
seconds or more) press of the button.
In the SLEEP mode the datalogger is
inactive, and the light does not blink.
Data can be downloaded from the
datalogger only when it is in the
RECORD or STANDBY modes.

OM-SC

$

235

OM-SC-KIT, $465, datalogger
complete with RS-232 cable
and DC voltage input cable.
Shown close to actual size.

E-53

E-54

E

Samples Length of

Sampling Intervals Per Hour Recording Session

0.88 seconds 4096 2 hours

1.76 seconds 2048 4 hours

3.52 seconds 1024 8 hours

7.03 seconds 512 16 hours

14.06 seconds 256 32 hours

0.47 minutes 128 2.66 days

0.94 minutes 64 5.33 days

1.88 minutes 32 10.8 days

3.75 minutes 16 3.02 weeks

7.5 minutes 8 6.1 weeks
15 minutes 4 12 weeks
30 minutes 2 5.63 months

1 hour 1 11.2 months

Specifications

No. of Channels: 1
Input Types: Temperature via

internal thermistor, DC voltage,
DC current, contact closure,
ambient light
Input Connection: DC voltage, DC
current, contact closure, ambient
light via plug-in cable
Measurement Range: DC voltage;
400 mV to 27 Vdc: DC current; 4 to
20 mA; temperature via internal
sensor; 0 to 70°C (32 to 158°F);
temperature via external sensor;

-55 to 140°C (-67 to 284°F); contact
closure; dry contacts: ambient light;
10 to 2000 lumens/sq. meter via
external ambient light sensor with
plug-in cable
Accuracy: DC Voltage; ±1.4% of
scale: DC Current; ±0.3 mA:
temperature; ±1.0 °C or better when
range of recorded temperature is
0 to 70 °C: ambient light; ±2 lumens
±20% of rdg
Resolution: DC Voltage; 0.4%
of scale: DC Current; 0.1 mA:
temperature; 0.3°C or better when
range of recorded temperature
is 0 to 70°C

Sample Rate: 4096/hr max
Data Storage: 8192 readings
Storage Technique:

Time extension recording

Power: 3V lithium battery
Battery Life: Up to 1 year of

continuous recording at 25°C

Operating Temperature:

-20 to 70°C (-4 to 158°F)

Storage Temperature:

-40 to 85°C (-40 to 185°F)

Relative Humidity:

0 to 100% non-condensing

Dimensions:

38 H x 57 W x 21 mm D
(1

1

⁄2 x 21⁄4 x 13⁄16")

Weight: 28 g (1 oz)

To Order

(Specify Model Number)

Model No. Price Description

OM-SC-KIT $465 Datalogger kit*
OM-SC 235 Portable datalogger
OM-SC-C-T 45 Remote temperature input cable, 20 to 80°C
OM-SC-C-HT 45 Remote temperature input cable, 25 to 140°C
OM-SC-C-LT 45 Remote temperature input cable, -55 to 25°C
OM-SC-C-I 95 Current (4 to 20 mA) input cable
OM-SC-C-V 45 DC voltage/contact closure input cable
OM-SC-C-AL 109 Ambient light sensor
OM-SC-S-I 118 Windows software (on CD ROM) and RS-232

cable with DB9F termination

* Includes OM-SC datalogger, OM-SC-C-T (temperature input cable), OM-SC-C-I (4 to 20 mA
input cable), OM-SC-C-V (DC voltage/contact closure input cable), OM-SC-C-AL (ambient
light sensor), and OM-SC-S-I (Windows software and RS-232 cable)

Comes with complete operator’s manual.

Ordering Example: OM-SC datalogger, OM-SC-C-T remote temperature input cable,
OM-SC-C-V voltage/contact closure input cable and OM-SC-S-I Windows software
and RS-232 cable, $235 + 45 + 45 + 118 = $443.

Accuracy

(Including

Range Resolution)

419 mV ±6 mV
851 mV ±12 mV

1.72 V ±24 mV

3.44 V ±48 mV

6.90 V ±96 mV

13.8 V ±192 mV

27.6 V ±384 mV

OM-SC-C-I

PC
SENSOR

TYPICAL
2 WIRE
TRANSMITTER

POWER
SUPPLY

Range

Input

BLK

RED

S

Z

-

-

-

-

+

+

+

+

LOAD

OR

LOAD

4/20mA LOOP

PS

PS

1

2

3

4

5

H

SINGLE RTD

3 WIRE

Recording Current
Loop Signals

Sampling