National Instruments FieldPoint cFP-RTD-122 Bedienungsanleitung

323348B-01 April 2003

FieldPoint™, National Instruments™, NI™, and ni.com™ are trademarks of National Instruments Corporation.

Product and company names mentioned herein are trademarks or trade names of their respective companies.

For patents covering National Instruments products,refer to the appropriate location: Help»Patents in your software,

the patents.txt file on your CD, or ni.com/patents.

FieldPoint Operating Instructions

FP-RTD-122 and

cFP-RTD-122

Eight-Channel Three-Wire RTD and

Resistance Input Modules

These operating instructions describe how to install and use the

National Instruments FP-RTD-122 and cFP-RTD-122 three-wire

RTD and resistance input modules (referred to inclusively as the

[c]FP-RTD-122). For details on configuring and accessing the

[c]FP-RTD-122 over a network, refer to the user manual for the

FieldPoint network module you are using.

Features

The [c]FP-RTD-122 is a FieldPoint RTD and resistance input

module with the following features:

• Inputs for 100 and 1,000 Ωplatinum RTDs (resistance

temperature detectors)

• Built-in linearization for six TCR (temperature coefficient of

resistance, or alpha) values of RTDs

• Direct resistance measurements in 400 and 4,000 Ωranges

• True three-wire compensation

• 16-bit resolution

• Filtering against 50 and 60 Hz noise

• Hot swappable

• 2,300 Vrms transient overvoltage protection

• –40 to 70 °C operation

FP-RTD-122 and cFP-RTD-122 2 ni.com

Installing the FP-RTD-122

The FP-RTD-122 mounts on a FieldPoint terminal base (FP-TB-x),

which provides operating power to the module. Installing the

FP-RTD-122 onto a powered terminal base does not disrupt the

operation of the bank.

To install the FP-RTD-122, refer to Figure 1 and complete the

following steps:

1. Slide the terminal base key to either position X, used for any

module, or position 1, used for the FP-RTD-122 module.

2. Align the FP-RTD-122 alignment slots with the guide rails on

the terminal base.

3. Press firmly to seat the FP-RTD-122 on the terminal base.

When the module is firmly seated, the terminal base latch locks

it into place.

Figure 1. Installing the FP-RTD-122

Installing the cFP-RTD-122

The cFP-RTD-122 mounts on a Compact FieldPoint backplane

(cFP-BP-x), which provides operating power to the module.

Installing the cFP-RTD-122 onto a powered backplane does not

disrupt the operation of the bank.

1 I/O Module

2TerminalBase

3 Alignment Slot

4Key

5Latch

6 Guide Rails

To install the cFP-RTD-122, refer to Figure 2 and complete the

following steps:

1. Align the captive screws on the cFP-RTD-122 with the holes

on the backplane. The alignment keys on the cFP-RTD-122

prevent backward insertion.

2. Press firmly to seat the cFP-RTD-122 on the backplane.

3. Using a number 2 Phillips screwdriver with a shank of at least

64 mm (2.5 in.) length, tighten the captive screws to 1.1 N ⋅m

(10 lb ⋅in.) of torque. The nylon coating on the screws prevents

them from loosening.

Figure 2. Installing the cFP-RTD-122

1 cFP-RTD-122

2 Captive Screws

3 cFP Controller Module

4 Screw Holes

5 cFP Backplane

3 5

FP-RTD-122 and cFP-RTD-122 4 ni.com

Wiring the [c]FP-RTD-122

The FP-TB-xterminal bases have connections for each of the eight

input channels on the FP-RTD-122. The cFP-CB-xconnector

blocks provide the same connections for the cFP-RTD-122.

Table 1 lists the terminal assignments for the signals associated

with each channel. The terminal assignments are the same for the

FP-TB-xterminal bases and the cFP-CB-xconnector blocks.

If you are using shielded wiring, you can reduce input signal noise

by connecting one end of the shield to the COM terminal. Do not

connect the shield to any of the wires at the signal end.

Taking RTD Measurements

with the [c]FP-RTD-122

The [c]FP-RTD-122 has eight input channels. All eight channels

share a common ground reference that is isolated from other

modules in the FieldPoint system. Each channel pulses a 0.25 mA

excitation current out of the EX+ terminal. The excitation current

returns through the COM terminal. The SENSE terminal measures

resistance and compensates for lead resistance errors. Each

channel is filtered, then sampled by a 16-bit analog-to-digital

converter.

Table 1. Terminal Assignments

Channel

Terminal Numbers

EX+ SENSE COM

0 1 2 18

1 3 4 20

2 5 6 22

3 7 8 24

4 9 10 26

5 11 12 28

6 13 14 30

7 15 16 32

Figure 3. [c]FP-RTD-122 Input Circuitry

Taking Measurements from Three-Wire RTDs

Three-wire RTDs often have a wire of one color (usually white,

sometimes red) for positive excitation, and two wires of another

color (usually red, sometimes black). Connect the positive

excitation wire to the EX+ terminal of the module, and connect the

other two wires to the SENSE and COM terminals.

Figure 4. Three-Wire RTD Connections on One Channel

Taking Measurements from Four-Wire RTDs

For the best accuracy, use the NI [c]FP-RTD-124 for input from

four-wire RTDs. Otherwise, leave any one of the RTD wires

unconnected and connect the remaining three as you would for a

three-wire RTD. Refer to Figure 5.

RTD

[c]FP-RTD-122

Pulsed

16-bit

ADC

Input

Circuitry

EX+

SENSE

COM

3-wire RTD

[c]FP-RTD-122

EX+

SENSE

COM

FP-RTD-122 and cFP-RTD-122 6 ni.com

Figure 5. Four-Wire RTD Connections on One Channel

Taking Measurements from Two-Wire RTDs

Connect either wire of a two-wire RTD to the EX+ terminal and the

other wire to the COM terminal, and connect a short jumper wire

between the COM and SENSE terminals.

Figure 6. Two-Wire RTD Connections on One Channel

Measuring Resistance Directly

You can use the [c]FP-RTD-122 to measure resistance in ohms.

In this way, you can take measurements from RTDs of types that

the [c]FP-RTD-122 does not directly support (such as 120 Ωnickel

RTDs) and from resistive devices other than RTDs. You can choose

one of two resistance ranges: 0–400 and 0–4,000 Ω. Resistance

values outside the range you select, including open circuits, result

in an Out of range error for the affected channels. The

[c]FP-RTD-122 ignores any configuration of RTD type for

channels with resistance ranges selected.

4-wire RTD

[c]FP-RTD-122

Leave this wire

unconnected

EX+

SENSE

COM

2-wire RTD

EX+

SENSE

COM

[c]FP-RTD-122

Short Jumper Wire

Converting Resistance Measurements

to Temperature Measurements

The [c]FP-RTD-122 has built-in linearization algorithms for

platinum RTDs of either 100 or 1,000 Ωnominal resistance,

and for six TCR (or alpha, α) values. The TCR is the average

temperature coefficient of resistance of an RTD from 0 to 100 °C.

This document specifies TCR in units of mΩ/Ω/°C.

The [c]FP-RTD-122 linearizes resistance values and returns

readings in units of temperature. The available ranges are

73 to 1,123 K, –200 to 850 °C, and –328 to 1,562 °F. You can

configure each channel independently, so you can connect different

types of RTDs to each channel.

Note You must configure each channel of the

[c]FP-RTD-122 for the RTD type connected to it. The

module does not automatically recognize RTD types.

RTD Types

RTD types are specified by material composition, nominal

resistance at 0 °C, and TCR. The [c]FP-RTD-122 can directly

measure the temperature of platinum RTDs of either 100 or

1,000 Ωnominal resistance. These RTDs are commonly referred to

as PT100 or PT1000 RTDs, respectively.

Different types of platinum RTDs have different TCRs. The

[c]FP-RTD-122 supports the following TCRs: 3.750, 3.851, 3.911,

3.916, 3.920, and 3.928 mΩ/Ω/°C. The most common TCR for

RTDs is 3.851 mΩ/Ω/°C. It is defined in international standards

such as IEC-751, DIN 43760, BS 1904, and ASTM E1137.

The TCR of 3.928 mΩ/Ω/°C is used in the reference function for

platinum thermometers in the International Temperature Scale

of 1990 (ITS-90) for high-accuracy metrology applications.

Unfortunately, not all TCR values are as well defined by standards

organizations, and the behavior of RTDs with the same TCR value

may vary from vendor to vendor. The variations are usually small,

and the built-in linearization algorithms of the [c]FP-RTD-122 are

appropriate for nearly all applications.

FP-RTD-122 and cFP-RTD-122 8 ni.com

The [c]FP-RTD-122 uses a linearization curve known as the

Callendar-Van Dusen equation to measure the temperature of

RTDs. The equation is as follows:

Temperatures below 0 °C:

RT= R0[1 + A × T+ B × T2+ C ×T3× (T– 100 °C)]

Temperatures above 0 °C:

RT= R0[1 + A ×T+ B ×T2]

T= temperature in °C

RT= RTD resistance at temperature T

R0= RTD nominal resistance at 0 °C

A, B, C are coefficients given in Table 2.

Table 2 lists the coefficients used in this equation for each of the

TCR values that the [c]FP-RTD-122 supports. If you have a

nonstandard RTD that does not match one of these linearization

curves, measure the resistance with the [c]FP-RTD-122 and

convert the resistance to temperature in the manner suggested by

the RTD vendor.

Three-Wire Compensation of Lead

Resistance Errors

The [c]FP-RTD-122 uses a three-wire compensation technique to

compensate for the lead resistances. The SENSE lead measures the

resistance of the return COM lead. If the EX+ lead has the same

resistance as the COM lead, the [c]FP-RTD-122 corrects for the

Table 2. Callendar-Van Dusen Coefficients Used by the [c]FP-RTD-122

TCR

mΩ/Ω/°C

(°C)–1

(°C)–2

(°C)–4

3.750a3.81 ×10–3 –6.02 ×10–7 –6.0 ×10–12

3.851b3.9083 ×10–3 –5.775 ×10–7 –4.183 ×10–12

3.911c3.9692 ×10–3 –5.8495 ×10–7 –4.233 ×10–12

3.916d3.9739 ×10–3 –5.870 ×10–7 –4.4 ×10–12

3.920e3.9787 ×10–3 –5.8686 ×10–7 –4.167 ×10–12

3.928f3.9888 ×10–3 –5.915 ×10–7 –3.85 ×10–12

effects of the leads. The only residual errors are those caused by

mismatching the EX+ and COM leads. Most RTDs have lead

resistances within 5% of each other, so the compensation of the

[c]FP-RTD-122 corrects for 95% or more of the errors introduced

by lead resistances. This is a more accurate method than the typical

bridge completion methods described in many reference books.

The bridge methods not only have the same sensitivity to lead

resistance mismatch, but also are effective only for temperatures

very near those at which the bridge is balanced (usually 0 °C).

The temperature measurement accuracy specifications for the

[c]FP-RTD-122 at the end of these instructions include the effects

of a typical application using 10 m of 22 gauge copper wire

(approximately 0.5 Ωper lead), with 5% mismatch in the lead

resistances. If you are using leads with greater resistances, the

additional errors are approximately 3 °C per Ωof mismatch in the

lead resistances for 100 ΩRTDs, and 0.3 °C per Ωof mismatch in

the lead resistance for 1,000 ΩRTDs. For example, for 2 Ωleads

matched to 5% of each other, the lead resistance mismatch is

5% ×2 Ω= 0.1 Ω, which would cause 0.3 °C of error in

measurements of a 100 ΩRTD.

If you are using the [c]FP-RTD-122 with two-wire RTDs, the

errors due to lead resistances are much greater because three-wire

compensation is not used. With two-wire RTDs, the additional

errors are approximately 3 °C per Ωof the sum of the lead

resistances for 100 ΩRTDs, and 0.3 °C per Ωof the sum of lead

resistances for 1,000 ΩRTDs. For example, a 1,000 Ωtwo-wire

RTD with 2 Ωleads has a total lead resistance of 4 Ω(2 Ωper lead),

which causes 1.2 °C of error.

Status Indicators

The [c]FP-RTD-122 has two green status LEDs, POWER and

READY. After you insert the [c]FP-RTD-122 into a terminal base

or backplane and apply power to the connected network module,

the green POWER indicator lights and the [c]FP-RTD-122

informs the network module of its presence. When the network

module recognizes the [c]FP-RTD-122, it sends initial

configuration information to the [c]FP-RTD-122. After the

[c]FP-AI-111 receives this initial information, the green READY

indicator lights and the module is in normal operating mode.

FP-RTD-122 and cFP-RTD-122 10 ni.com

Upgrading the FieldPoint Firmware

You may need to upgrade the FieldPoint firmware when you add

new I/O modules to the FieldPoint system. For information on

determining which firmware you need and how to upgrade your

firmware, go to ni.com/info and enter fpmatrix.

Isolation and Safety Guidelines

Caution Read the following information before

attempting to connect the [c]FP-RTD-122 to any circuits

that may contain hazardous voltages.

This section describes the isolation of the [c]FP-RTD-122 and its

compliance with international safety standards. The field wiring

connections are isolated from the backplane and the inter-module

communication bus. The isolation is provided by the module,

which has optical and galvanic isolation barriers designed and

tested to protect against transient fault voltages of up to 2,300 Vrms.

Follow these guidelines to ensure a safe total system:

• The [c]FP-RTD-122 has a safety isolation barrier between the

I/O channels and the inter-module communication bus. There

is no isolation between channels unless otherwise noted. If any

of the channels on a module are wired at a hazardous potential,

make sure that all other devices or circuits connected to that

module are properly insulated from human contact.

•Donot share the external supply voltages (the V and C

terminals) with other devices (including other FieldPoint

devices), unless those devices are isolated from human contact.

• For Compact FieldPoint, you must connect the protective earth

(PE) ground terminal on the cFP-BP-xbackplane to the system

safety ground. The backplane PE ground terminal has the

following symbol stamped beside it: . Connect the

backplane PE ground terminal to the system safety ground

using 14 AWG (1.6 mm) wire with a ring lug. Use the 5/16 in.

panhead screw shipped with the backplane to secure the ring

lug to the backplane PE ground terminal.

• As with any hazardous voltage wiring, make sure that all

wiring and connections meet applicable electrical codes and

commonsense practices. Mount terminal bases and backplanes

in an area, position, or cabinet that prevents accidental or

unauthorized access to wiring that carries hazardous voltages.

Dieses Handbuch passt für folgende Modelle

Inhaltsverzeichnis

Andere National Instruments Netzwerk-Hardware Handbücher

National Instruments

National Instruments NI 9149 Bedienungsanleitung

National Instruments

National Instruments NI WLS/ENET-9163 Bedienungsanleitung

National Instruments

National Instruments GPIB-100 Bedienungsanleitung

National Instruments

National Instruments GPIB Series Bedienungsanleitung

National Instruments

National Instruments DAQ PCI-4451 Bedienungsanleitung

National Instruments

National Instruments PXI Terminal Block NI TB-2708 Bedienungsanleitung

National Instruments

National Instruments IMAQ PCI-1411 Bedienungsanleitung

National Instruments

National Instruments NI Vision CVS-1454 Bedienungsanleitung

National Instruments

National Instruments USB Digitizers NI USB-5132 Bedienungsanleitung

National Instruments

National Instruments 2806 Bedienungsanleitung

National Instruments

National Instruments FIELDPOINT FP-1600 Bedienungsanleitung

National Instruments

National Instruments NI 9203 Bedienungsanleitung

National Instruments

National Instruments SCB-68 Bedienungsanleitung

National Instruments

National Instruments GPIB GPIB-ENET/100 Bedienungsanleitung

National Instruments

National Instruments NI 9375 Bedienungsanleitung

National Instruments

National Instruments FIELDPOINT cFP-DO-403 Bedienungsanleitung

National Instruments

National Instruments SC-2040 Bedienungsanleitung

National Instruments

National Instruments NI 447 Series Bedienungsanleitung

National Instruments

National Instruments AT-232/2 Bedienungsanleitung

National Instruments

National Instruments NI Vision CVS-1456 Bedienungsanleitung

National Instruments

National Instruments NI WAP-3701 Bedienungsanleitung

National Instruments

National Instruments NI-488.2 Bedienungsanleitung

National Instruments

National Instruments R Series Bedienungsanleitung

National Instruments

National Instruments NI ELVIS III Bedienungsanleitung

Beliebte Netzwerk-Hardware Handbücher anderer Marken

Matrix Switch Corporation

Matrix Switch Corporation MSC-HD161DEL Bedienungsanleitung

B&B Electronics

B&B Electronics ZXT9-IO-222R2 Bedienungsanleitung

Yudor

Yudor YDS-16 Bedienungsanleitung

D-Link

D-Link ShareCenter DNS-320L Bedienungsanleitung

Samsung

Samsung ES1642dc Gebrauchsanweisung

Honeywell Home

Honeywell Home LTEM-PV Montageanleitung

evertz

evertz 7700 Series Bedienungsanleitung

D-Link

D-Link ShareCenter DNS-343 Bedienungsanleitung

Asante

Asante AsanteBridge 1012 Bedienungsanleitung

FireBrick

FireBrick FB2700 Bedienungsanleitung

Audiovox Electronics

Audiovox Electronics ARWH2T Bedienungsanleitung

ADC

ADC DSX-1 Handbuch

NetComm

NetComm NF2 Bedienungsanleitung

Alcatel-Lucent

Alcatel-Lucent 5620 Bedienungsanleitung

Dell EMC

Dell EMC XC6420 Series Bedienungsanleitung

Lanner

Lanner NCA-1020A Bedienungsanleitung

Allied Telesis

Allied Telesis AT-TN121-A Bedienungsanleitung

Lanner

Lanner NCA-1525 Bedienungsanleitung