ROC800-Series Instruction Manual
Revised July-2017 Communications 5-11
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
communication 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 EIA-422/485 (RS-422/485) communication are
19200 baud rate, 8 data bits, 1 stop bit, and no parity. The maximum
rate is 57.6 Kbps.
EIA-422/485 (RS-422/485) communication modules include LED
indicators that display the status of receive and transmit activity. Refer
to Tables 5-8 and 5-9.
Table 5-8. EIA-422 (RS-422) Signal Routing – Comm3, Comm4, and Comm5
Lit when module (Comm3, Comm4, or Comm5) is currently receiving.
Lit when module (Comm3, Comm4, or Comm5) is currently transmitting.
Table 5-9. EIA-485 (RS-485) Signal Routing – Comm3, Comm4, and Comm5
Lit when module (Comm3, Comm4, or Comm5) is currently receiving.
Lit when module (Comm3, Comm4, or Comm5) is currently transmitting.
You can induce ground loops by tying commons from various modules
together.
EIA-422/485 (RS-422/485) communication provides EIA-422/485 (RS-
422/485) signals on the Comm3, Comm4, or Comm5 port, depending
on where you have installed the module. Wiring should be twisted-pair
cable, one pair for transmitting, and one pair for receiving. The EIA-422
(RS-422) module uses four wires and the EIA-485 (RS-485) uses two
wires for connectivity.
5.8.1 EIA-422/485 (RS-422/485) Jumpers & Termination Resistors
Four jumpers—J3, J4, J5, and J6—are located on the EIA-422/485 (RS-
422/485) communication module (see Figure 5-5). These jumpers
determine the mode in which the module runs (RS-422 or RS-485) and
if the module is terminated.
To Next Page
Loading...
Need help?
General
