Yokogawa VJA7 User Manual

User’s Manual

IM 77J01A07-01E

Model VJA7 Distributor (Multi-function)

(Isolated Single-output and Isolated Dual-output Types)

1. CAUTIONARY NOTES FOR SAFE USE OF THE PRODUCT

For the correct use of this product, read through this manual before use. The following safety symbol is indicated on the product to ensure safe use.

CAUTION

If this symbol is indicated on the product, the operator should refer to the explanation given in the instruction manual in order to avoid personnel injury or death to either themselves or other personnel, and/or damage to the instrument. The manual describes the special care the operator should exercise to avoid shock or other dangers that may result in injury or loss of life.

The following symbol marks are used only in this manual.

IMPORTANT

Indicates that operating the hardware or software in a particular manner may damage it or result in a system failure.

NOTE

Draws attention to information that is essential for understanding the operations and/or features of the product.

4. MOUNTING METHODS

4.1 Wall Mounting

Loosen the main unit-fixing screw of the distributor to disconnect the main unit from the socket. Next, anchor the socket onto the wall with screws. Then, plug the main unit into the socket and secure the main unit with the main unit-fixing screw.

Socket

Threaded hole for fixing the main unit

Main unit

Main unit-fixing screw

29.5 or more 22±0.2

2-M4 or 2-ø4.5 or more

Unit: mm

Mounting screws

2. CHECKING PRODUCT SPECIFICATIONS AND THE CONTENTS OF PACKING

(1) Model Number and Specification Check

Check that the model number and specifications shown on the nameplate attached on the side of the product are as ordered.

(2) Contents of the Packing

Check that the packing contains the following items:

● VJA7 main unit, 1

● Instruction Manual (IM 77J1A07-01E), 1

● Tag number label, 1

3. GENERAL

This distributor, which belongs to the JUXTA series of signal conditioners, receives 4 to 20 mA DC signals from two-wire transmitters while supplying power to transmitters and converting the received signal to pairs of isolated current and voltage signals.

• Output-2 signal is selectable from a DC voltage signal, DC

current signal, communication function (RS-485), and alarm output (two relay contacts).

59±0.3

Fig. 4.1

4.2 DIN Rail Mounting

Locate the distributor so that the DIN rail fits into the upper part of the DIN-rail groove at the rear of the socket, and fasten the socket using the slide lock at the lower part of the socket.

DIN rail

VIEW A

Fig. 4.2

VIEW A (Rear of socket)

DIN rail

Slide lock

Keep this manual in a safe place.

Network Solutions Business Divisiion

2-9-32, Naka-cho Musashino-shi, Tokyo 180-8750 Japan Phone: +81-422-52-7179 Facsimile: +81-422-52-6793

IM 77J01A07-01E

1st Edition Nov. 1999

2nd Edition June 2004

NOTE

4.3 Mounting Using a Multi-mounting Base

For mounting using a multi-mounting base, see the Instruction Manual for VJCE (VJ Mounting Base).

4.4 Using Ducts

Wiring ducts should be installed at least 30 mm away from the top or bottom of the main unit.

4.5

In case of top-and-bottom close mounting

Transmitter should be mounted horizontally with its top and bottom slits being vertical. The top and bottom slits should not be covered. The area for wiring is required above and below the transmitter (the area with slant lines).

40 or more40 or more

ALM1

ALM2

29.5 or more

ALM1

ALM2

(72)

(29.5)

78 or more

150 or more

ALM2

ALM1

ALM2

• For mounting, use M3 screws and crimp-on terminals with insulating sleeves appropriate for the wires used. Tool of the crimp-on terminals to be used should be appropriate for the crimp-on terminals.

• Mount a breaker on the external place. Mount a switch or 5A circuit breaker on the place near by the instrument, within operator’s reach. And attach the indication that it is for disconnecting the instrument.

Input signal

Example of using

COM

ALM1

COM

ALM2

a Zener barrier to configure an intrinsically safe system

PS+

RS-485

B+

A-

COM

communication

3 2

1011

1 4

789

When internal power is used

PS+

COM

Output-2 signal

Analog output

Output-1 signal

Analog output

When external power is used

Alarm output

Fig. 4.3

5. INSTALLATION LOCATION

• For installation, avoid any location where the product may be subject to vibrations, corrosive gases, or large amounts of dust, or where the product is exposed to water, oil, solvents, direct sunlight, radioactive rays, or strong electric or magnetic fields.

• If there is a possibility that lightening could induce a high surge voltage on the power and signal lines, provide lightening arresters on the line between the field instrument and indoor instrument in order to protect the product. Install a dedicated arrester on the field side and another on the indoor side.

6. EXTERNAL WIRING

WARNING

Turn OFF the power supply and make sure that none of the cables are not in the hot-line state before carrying out the wiring to avoid the possibility of electric shock.

Wires are connected to the terminals of the distributor’s socket. M3 screw terminals are provided for the connection of external signals. Attach a crimp-on lug to each wire for connection to the terminals.

• Recommended cables: A nominal cross-sectional area of 0.5 mm2 or thicker for signal cables, and that of 1.25 mm2 or thicker for power cables, and shielded twisted-pair cables (AWG24) for communication wiring cables.

Power Supply

L+

N-

GND

Fig. 6.1

● Keep all sources of noise away from the power and sig-

nal cables. Otherwise, accuracy cannot be assured.

● Provide grounding to a grounding resistance of 100 ⍀.

The length of the grounding cable should be 20 m or less. Directly connect the lead from the ground terminal (terminal no. 8) of the distributor to the ground. Do not carry out daisy-chained inter-ground terminal wiring.

● Direct Current

●

“Overvoltage category (Installation category)” describes a number which defines a transient overvoltage condition. It implies the regulation for impulse withstand voltage. “II” applies to electrical equipment which is supplied from the fixed installation like distribution board.

●

“Pollution degree” describes the degree to which a solid, liquid, or gas which deteriorates dielectric strength or surface resistivity is adhering. “2” applies to normal indoor atmosphere. Normally, only non-conductive pollution occurs. Occasionally, however, temporary conductivity caused by condensation must be expected.

● Rated fuse of 125VDC, 1A is stored. However, opera-

tors can not replace the fuse.

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