ROC827 Instruction Manual

The EIA-232 (RS-232) communications includes LED indicators that display the status of the Receive (RX), Transmit (TX), Data Terminal Ready (DTR), and Ready To Send (RTS) control lines.

Table 5-7 defines the built-in EIA-232 (RS-232) terminals at the Comm2 port and their function signals.

Table 5-7. Built-in EIA-232 (RS-232) Signal Routing – Comm2

Signal

LED Function

Terminal

RX

Lit when Comm2 is currently receiving.

1

TX

Lit when Comm2 is currently transmitting.

2

RTS

Lit when Comm2 ready to send is not active.

3

DTR

Lit when Comm2 data terminal ready is active.

4

GND

Common.

5

The EIA-232 (RS-232) communications module provides for EIA-232 (RS-232C) signals on the Comm3, Comm4, or Comm5 port depending on where the module is installed. Refer to Table 5-8.

Table 5-8. EIA-232 (RS-232) Communication Module Signal Routing – Comm3, Comm4, and Comm5

Signal

LED Function

Terminal

RX

Lit when module (Comm3, Comm4, or Comm5) is

1

 

currently receiving.

 

TX

Lit when module (Comm3, Comm4, or Comm5) is

2

 

currently transmitting.

 

RTS

Lit when module (Comm3, Comm4, or Comm5) is

3

 

ready to send is not active.

 

DTR

Lit when module (Comm3, Comm4, or Comm5)

4

 

data terminal ready is active.

 

GND

Common.

5

5.8EIA-422/485 (RS-422/485) Serial Communications Module

EIA-422/485 (RS-422/485) communication modules meet all EIA- 422/485 (RS-422/485) specifications for differential, asynchronous serial communication transmissions of data over distances of up to 1220 meters (4000 feet). EIA-485 (RS-485) communications are commonly used to multi-drop units on a serial network over long distances using inexpensive twisted-pair wiring.

EIA-422 (RS-422) drivers are designed for party-line applications where one driver is connected to, and transmits on, a bus with up to ten receivers. EIA-422 (RS-422) allows long distance point-to-point communications and the drivers are designed for true multi-point applications with up to 32 drivers and 32 receivers on a single bus.

The default values for the EIA-422/485 (RS-422/485) communications are 19200 Baud Rate, 8 Data Bits, 1 Stop Bit, and No Parity. The maximum rate is 57.6K bps.

Issued Mar-06

Communications

5-10

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Image 102
Emerson ROC827 EIA-422/485 RS-422/485 Serial Communications Module, Built-in EIA-232 RS-232 Signal Routing Comm2