Rockwell Automation 1770-HT8 SMART TRANSMITTER User Manual

Page 50

Installing the Smart Transmitter Interface

Products

Chapter 2

2-25

Table 2.A

RSĆ232C Connector Pinouts

Signal

Abbreviation

I/O

Direction

Pin Number Meaning

БББББ

БББ

Chassis Ground

БББББ

БББ

N/A

ББББ

ББ

ББББ

ББ

ББББББББББББББББББ

ББББББББББББББББ

The cable shield must be connected to chassis ground at one end only.

It is recommended that you do this at the Communications Controller end.

БББББ

БББ

Transmit Data

БББББ

БББ

TXD

ББББ

ББ

Output

ББББ

ББ

ББББББББББББББББББ

ББББББББББББББББ

RSĆ232C serialized data output from the Communications Controller.

БББББ

БББ

Receive Data

БББББ

БББ

RXD

ББББ

ББ

Input

ББББ

ББ

ББББББББББББББББББ

ББББББББББББББББ

RSĆ232C serialized data input to the Communications Controller.

БББББ

БББ

Request to Send

БББББ

БББ

RTS

ББББ

ББ

Output

ББББ

ББ

ББББББББББББББББББ

ББББББББББББББББ

A request from the Communications Controller to the modem to prepare to

transmit. With full duplex protocol, RTS is always asserted. With half

duplex protocol, it is turned on when the Communications Controller has

permission to transmit, otherwise it is off.

БББББ

БББ

БББББ

Clear to Send

БББББ

БББ

БББББ

CTS

ББББ

ББ

ББББ

Input

ББББ

ББ

ББББ

ББББББББББББББББББ

ББББББББББББББББ

ББББББББББББББББББ

A signal from the modem to the Communications Controller that indicates

the carrier is stable and the modem is ready to transmit. The

Communications Controller will not transmit until CTS is on. If CTS is

turned off during transmission, the Communications Controller will stop

transmitting until CTS is restored.

БББББ

БББ

БББББ

Data Set Ready

БББББ

БББ

БББББ

DSR

ББББ

ББ

ББББ

Input

ББББ

ББ

ББББ

ББББББББББББББББББ

ББББББББББББББББ

ББББББББББББББББББ

A signal from the modem to the Communications Controller that indicates

the phone is off-hook. It is the modem's answer to DTR. The

Communications Controller will not transmit or receive unless DSR is on. If

the modem does not control DSR properly, DSR must be jumpered to a

high signal at the Communications Controller. (It can be jumpered to

DTR.)

БББББ

Signal Ground

БББББ

GND

N/A

ББББ

ББББББББББББББББББ

Signal ground - a reference point for the data signals.

БББББ

БББ

БББББ

Data Carrier

Detect

БББББ

БББ

БББББ

DCD

ББББ

ББ

ББББ

Input

ББББ

ББ

ББББ

ББББББББББББББББББ

ББББББББББББББББ

ББББББББББББББББББ

A signal from the modem to the Communications Controller to indicate

that the carrier from another modem is being sensed on the phone line. It

will not be asserted unless the phone is off-hook. Data will not be

received by the Communications Controller unless DCD is on. With full

duplex protocol, the Communications Controller will not transmit unless

DCD is on. If the modem does not control DCD properly, DCD must be

jumpered to DTR at the module.

БББББ

БББ

БББББ

Data Terminal

Ready

БББББ

БББ

БББББ

DTR

ББББ

ББ

ББББ

Output

ББББ

ББ

ББББ

ББББББББББББББББББ

ББББББББББББББББ

ББББББББББББББББББ

A signal from the Communications Controller to the modem to connect to

the phone line (i.e., "pick up the phone"). The Communications Controller

will assert DTR all the time except during the phone hang-up sequence.

Modems built to North American standards will not respond to DTR until

the phone rings. The Communications Controller will not work correctly

with modems which always pick up the phone upon receiving DTR,

whether the phone is ringing or not.

The connector you use at the computer end of the cable depends on
whether or not your application makes use of handshake signals, whether
or not you are connecting to a 9 pin serial port for an IBM AT, and whether
or not your computer uses standard IBM pinouts. The following diagrams,
Figure 2.21 through Figure 2.26, are for IBM computers with either 9 or 25
pin connectors. If your computer has a different pinout, construct a cable
using the appropriate signal names for your computer.

If you are not using handshake signals, use the three wire connections
shown in Figure 2.21 or Figure 2.22.

This manual is related to the following products:

1770-HT16 SMART TRANSMITTER 1770-HT1 SMART TRANSMITTER