Measurement DBK52 User Manual

DBK52 14-Channel Thermocouple Input Module

Overview …… 1
Hardware Setup …… 2

Module Connection …… 2
Module Configuration …… 3
DaqBook/100 Series & /200 Series and DaqBoard [ISA type] Configuration …… 3
DaqBook/2000 Series and DaqBoard/2000 Series Configuration …… 3

Software Setup …… 4
DBK52 – Specifications …… 4

Reference Notes:

o Chapter 2 includes pinouts for P1, P2, P3, and P4. Refer to pinouts applicable to

Overview

The DBK52 provides the ability to scan and input thermocouple data for various computer-based
temperature-monitoring systems. Features include:

• Each DBK52 can connect up to 14 thermocouples. Up to 16 DBK52s may attach to a single

your system, as needed.

o In regard to calculating system power requirements, refer to DBK Basics located

near the front of this manual.

DaqView Users: When DBK52 is used with /2000 Series Devices, the Internal Clock Speed
should be set to 100 kHz as described in Chapter 3, DBK Setup in DaqView.

LogBook or Daq Device to measure a maximum of 224 (16 × 14) temperatures.

• Standard, miniature jacks can connect to all T/C types.

• Onboard cold junction sensor (CJS) circuitry is accessible via a built-in channel to the system.

• A built-in short-to-ground channel back to the system eliminates offset errors via software.

• RC low-pass input filters reject high frequency noise for thermocouple shields.

• An external analog-common access jack provides a bias-current return path for differential

signal inputs.

• An onboard programmable gain amplifier supports most thermocouple types and temperature

ranges.

• Software-based linearization (in LogView and DaqView) converts analog signals into

temperature values.

Reference Note:

In regard to Daq devices, related material for programmers is included in the separate
Programmer’s Manual (p/n 1008-0901).

The following table shows the temperature range for each thermocouple type.

T/C Type J K T E N28 N14 S R B
Temperature
Range °C
Temperature
Range °F

-200 to
760

-328 to
1400

-200 to
1260

-328 to
2300

-200 to
400

-328 to
752

-270 to
1000

-454 to
1832

-270 to
400

-454 to
752

0 to
1300

32 to
2372

0 to
1780

32 to
3236

0 to
1780

32 to
3236

0 to
1820

32 to
3308

Thermocouple accuracy depends on the thermocouple itself, the cold-junction sensor, A/D conversion, and
linearization. The DBK52, LogBook, and Daq device systems use quality components and software
compensation to minimize error from these sources. Systems achieve a ±1°C CJS accuracy that contributes
to the overall accuracy. When the software is calibrated, gain and offset errors are virtually eliminated.
The DBK52’s built-in auto-zero channel dynamically eliminates any other system offset-errors.

DBK Option Cards and Modules 989594 DBK52, pg. 1

True differential measurements of T/Cs require bias-current referenced to the analog common. Resistors
from each input T/C are connected to the analog common. Filter capacitors across each input operate with
input protection resistors to form a single-pole RC low-pass filter.

Hardware Setup

Module Connection

The DBK52 has miniature T/C jacks to connect different types of thermocouples and an analog-ground
access point. Connections are provided for 14 thermocouples. Thermocouple polarities must be
observed. Thermocouple types J, K, T, E, N28, N14, S, R and B are supported by the LogView or
DaqView software and may be connected to DBK52 board channels CH2 through CH15.

Note: CH0 is reserved for the cold-junction compensation sensor (factory installed).

Thermocouple wire is standardized and color-coded as shown in the table. T/Cs have a very small output.
Long T/C leads can pickup lots of noise. Use shielding as needed, and average several readings in
software to minimize noise effects.

T/C
Type

J White Red
K Yellow Red
T Blue Red
E Violet Red
N28 Orange Red
N14 Orange Red
S Black Red
R Black Red
B Gray Red

(+) Lead to
Channel-Hi

(-) Lead to
Channel-Lo

CH1 is permanently shorted to allow software-driven auto-zero to compensate for
temperature drift.

After all connections are in place, secure wires to captive areas (pre-drilled holes) at the rear edge of the
board. Nylon tie wraps (not included) work well for this purpose.

DBK52, pg. 2 989594 DBK Option Cards and Modules