Q Corresponding Serial Communication Module User's Manual

3 SPECIFICATIONS

MELSEC-Q

3.2 RS-232 Interface Specification

The following shows the RS-232 interface specifications.

3.2.1 RS-232 connector specifications

The following shows the specifications of the RS-232 connector that connects the Q series C24 to an external device.

1

4

5

2

3

Full-duplex communication

Half-duplex communication

8

9

6

7

Pin number

Signal abbreviation

7

8

5

6

9

3

4

1

2

CD

RD(RXD)

SD(TXD)

DTR(ER)

SG

DSR(DR)

RS(RTS)

CS(CTS)

RI(CI)

Signal name

Carrier detect

Receive data

Send data

Data terminal ready

Signal ground

Dataset ready

Request to send

Clear to send

Call Indicate

C24

Signal direction

External device

(1) The control signals are described below. (The pin numbers of the connector are enclosed in parentheses.)

1) CD signal (1)

• The Q series C24 operates according to the setting CD terminal check (see

Section 8.4.5) of the Q series C24.

CD terminal check enabled CD terminal check disabled

• The Q series C24 performs send and receive processing when the CD signal (receive carrier detection) is ON.

• If the CD signal is turned off during data communication, the Q series C24 initializes the transmission sequence.

• The Q series C24 performs send and receive processing regardless of the ON/OFF status of the CD signal.

• Data communications is possible with an external device that cannot turn the CD signal ON/OFF.

See Chapter 8 of User's Manual (Application) Setting impossible.

2) RD signal

This is a signal to receive data.

3) SD signal

This is a signal to send data.

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3 SPECIFICATIONS

MELSEC-Q

4) DTR signal (4)

• When communicating data using the non procedure protocol, the Q series

C24 turns on or off (on when data is receivable) depending on the amount of unused memory in the OS area allocated for receive data storage, if

DTR/DSR control is being performed.

Read the receive data from the sequence program, as the receive data is stored in the OS area when the DTR signal is OFF.

If DTR/DSR control is not implements, the DTR signal is always ON.

• If an MC protocol or bidirectional protocol is performing data communication, the Q series C24 turns ON when communications is enabled.

5) DSR signal (6)

• During DTR/DSR control, if this signal is OFF, the Q series C24 does not send data to the external device.

Be sure that this signal is always turned ON when the external device is ready to receive.

• If DTR/DSR control is not implemented, the DSR signal status is ignored.

6) RS signal (7)

• The Q series C24 turns ON/OFF the RS signal as shown below.

• When the communication system is full-duplex communications, if the Q series

C24 ready signal (X1E) is ON, the Q series C24 turns ON the RS signal.

• When the communication system is half-duplex communications, when the

Q series C24 sends data to an external device, it turns ON the RS signal.

• The RS signal is not turned OFF even when the receive data cannot be stored in the Q series C24.

7) CS signal (8)

• The Q series C24 does not send data to an external device when this signal is OFF.

• Be sure that this signal is always turned ON when the external device is ready to receive.

8) RI signal (9)

• The RI signal is used when the modem status is monitored on the Q series

C24 side. It should be connected as needed. The RI signal is not needed to be connected when the modem is not connected.

(2) The ON and OFF states of each signal indicate the following conditions:

(Output side) (Input side)

ON ……… 5 V DC to 15 V DC, 3 V DC to 15 V DC

OFF ……… –5 V DC to –15 V DC, –3 V DC to –15 V DC

(3) Interface connector

The Q series C24 uses the following type of RS-232 interface connector.

9-pin D sub (female) screw fixing type

Use one of the following as a connector shell for the connection cable of the Q series C24 side.

• 3M

Plug model: 8209-6009

• Tyco Electronics AMP K.K.

Plug model: 747904-2

Shell model: 3702-2209 M2.6

Shell model: 747515 or 174469-2

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3 SPECIFICATIONS

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REMARK

(1) Confirmation of RS-232 control signal status

The control signal status of DTR, DSR, RS, and CD can be confirmed during data communication by the RS-232 control signal status storage area (address

254

H

, 264

H

) of the GX Configurator-SC or Q series C24 buffer memory.

Buffer memory address

Bit position CH1 side

254

H

CH2 side

264

H b0 b1 b2 b3 b4 b5 b6 to b15

1 System area for QJ71C24 (-R2)

RS

DSR

DTR

CD

CS

1

RI

—

(2) Designation of RS and DTR signal status

When the Q series it turned on or off, the on and off states of the RS and DTR signals can be designated when the buffer memory of the RS and DTR signal status designation area (address: 92

H

, 132

H

) for the corresponding bit is turned on or off by the RS signal or DTR signal.

1 2 3

Buffer memory address 92

H

/132

H b15 b3 b2 b1 b0

1/0 1/0

[Default 0005

H

]

System

RS

DTR

1:ON

0:OFF

1 The RS signal is controlled by the Q series C24 in the following cases. (Ignore setting contents.)

• When data is communicated with half-duplex communication

• When communication time and the RS and CS signals are controlled by the modem function

2 The DTR signal is controlled by the Q series C24 in the following cases. (Ignore setting contents.)

• When the DTR and DSR signals are controlled

• When data is communicated by the modem function

3 After writing in the buffer memory, a lag of 0 to 20 ms occurs until it is reflected in the signal.

POINT

Be sure to control the RS and DTR signals with the Q series C24. Control of the RS and DTR signals by the user is a prime factor for data communication errors.

3.2.2 RS-232 cable specification

• Use a 15 m (49.21 ft.), or shorter, cable conforming to the RS-232 standard as the

RS-232 cable.

(Recommended cable)

7/0. 127 P HRV-SV… : Designates the number of pairs. (For 13 pairs 7/0.127

13P HRV-SV)

(Oki Electric Cable Co., Ltd)

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