Omega Products CN7400 Installation Manual

User’s Guide

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CN7400

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CN7400 Temperature Control

Specifications - Installation and Operating Instructions

OMEGA Engineering
One Omega Drive, Stamford, Connecticut 06907-0047
P.O. Box 4047

Page 1 of 25

Telephone
800/848-4286 or 203/359-1660
Fax
203/359-7700

CONTENTS

MODEL IDENTIFICATION.....................................................................2

GETTING STARTED.............................................................................3

INSTALLATION.....................................................................................4

WIRING................................................................................................5

Wiring for 4 to 20mA Transmitter inputs.....................................6

Wiring for Optional Inputs and Outputs......................................6

FRONT PANEL KEY FUNCTIONS........................................................8

NOTATION CONVENTIONS FOR THE MENUS..................................10

THE HOME DISPLAY..........................................................................11

OPERATION AND PROGRAMMING OF OPTIONS.............................11

PRIMARY MENU................................................................................13

SECONDARY MENU..........................................................................13

SECURE MENU.................................................................................15

DIAGNOSTIC ERROR MESSAGES....................................................20

SPECIFICATIONS...............................................................................22

DIMENSIONS.....................................................................................24

MODEL IDENTIFICATION

CN74

Output A
3 = N.O. Relay

Output B
0 = None
4 = N.C. Relay

Options
PV1 = 0-20 mA

Options:

PV1 Analog Retransmission of Process Variable, 4 to 20 mAdc.
LV 12 - 24 Vdc/Vac 50 - 400 Hz power supply (control operates on

low voltage equipment).

Page 2 of 25

GETTING STARTED

1. Install the control as described on page 4.

2. Wire your control following the instructions on page 5. If you are using a
two-wire transmitter as a input, see the drawing and instructions on page 6.
Option wiring instructions are on page 7. Option descriptions are specific
instructions start on page 16.

3. Most controls do not need many (if any) program changes to work on your
process. For best results when programming changes are necessary, make all
the necessary changes in the Secure Menu (page 26) before making changes
to the Secondary Menu (page 19). If error messages occur, check the
Diagnostic Error Messages on page 35 for help.

Take the example of a Model CN7430 that comes from the factory
programmed for type J thermocouples. Suppose for this example you wish to
change the input to type K and limit the set point range between 0° and
1000°C.

First, enter the Secure menu as instructed on Page 5. Press the INDEX key
until the display shows
shows

CCAA

. Don’t forget to press the ENTER key to retain your setting.

IInnpp

and press the DOWN ARROW until the display

Next, press the INDEX key to display
display shows CC. Press ENTER.

Next, press the INDEX key until
selections). Press the UP ARROW until the display shows 00. Press ENTER.

Finally, press INDEX key to display
display shows

The necessary program changes are now complete. After 30 seconds the
display will switch back to the temperature reading. If you want to return faster,
press the UP ARROW and ENTER keys (at the same time) and then press the
DOWN ARROW and INDEX keys (again at the dame time). This will ‘back out’
of the menu and immediately display the temperature reading.

11000000

. Press ENTER.

UUnniitt

. Press the DOWN ARROW until the

SSPPLL

is displayed (pass the

SSPPHH

. Press the DOWN ARROW until the

Page 3 of 25

ddPPtt

and

IInnPPtt

INSTALLATION

Mount the instrument in a location that will not be subject to excessive
temperature, shock, or vibration. All models are designed for mounting in an
enclosed panel.

Select the position desired for the instruments on the panel. If more that one
instrument is required, maintain the minimum of spacing requirements as
shown on the drawing below. Closer spacing will structurally weaken the
panel, and invalidate the IP66, UL type 4 rating of the panel.

Prepare the panel by cutting and deburring the required opening.

From the front of the panel, slide the housing through the cut out. The housing
gasket should be against the housing flange before installing.

From the rear of the panel slid the
mounting collar over the housing.
Hold the housing with one hand
and using the other hand, push
the collar evenly against the panel
until the spring loops are slightly
compressed. The ratchets will
hold the mounting collar and
housing in place.

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Page 4 of 25

WIRING

Do not run thermocouple or other class 2 wiring in the same conduit as power
leads. Use only the type of thermocouple or RTD probe for which the control
has been programmed. Maintain separation between wiring of sensor, auxiliary
in or out, and other wiring. See the “Secure Menu” for input selection.

For thermocouple input always use extension leads of the same type
designated for your thermocouple.

For supply connections use No. 16 AWG or larger wires rated for at least 75°C.
Use copper conductors only. All voltage output circuits must have a common
disconnect and be connected to the same pole of the disconnect.

Input wiring for thermocouple, current, and RTD; limit reset function; and output
wiring for the 15VCD is rated CLASS 2.

Control wiring is as shown.

Alarm Reset

An external
normally open
contact may be
wired across
terminals 9 and
10 for remote
reset.
Multiple units
can not share
common
contacts.
Terminals 9 and
10 share a
common
ground with the
input.

• For 2-wire RTD use terminals 1 & 3 and place a jumper wire between
terminal 3 & 4.

Page 5 of 25

Output A Relay (N.O.) wires to terminals 15 & 16.
Output B Relay (N.C.) wires to terminal 17 & 18.

Wiring for 4 to 20mA Transmitter inputs

Wire power and outputs as shown above. Two-wire transmitters wire as shown
below.

For three of four wire transmitters follow the wiring instructions provided with
your transmitter.

CAUTION: DO NOT WIRE THE 24 VOLT POWER
SUPPLY ACROSS THE INPUT OF THE CONTROL.
DAMAGE TO THE CONTROL INPUT CIRCUITRY WILL
RESULT

Wiring for Optional Inputs and Outputs

Wire power outputs as shown on page 5 and 6. Wiring for options is shown
opposite. All wiring shown below is Class 2.

Page 6 of 25

CAUTION: DO NOT RUN SIGNAL WIRING IN THE
SAME CONDUIT OR CHASE AS THE POWER
WIRING. ERRATIC OPERATION OR DAMAGE TO
THE CONTROL CIRCUITRY WILL RESULT.

OPTION

PV1

11

+

12

-

6

NA

7

NA

8

NA

Page 7 of 25