CHAPTER 1: OVERVIEW
SNAP PAC S-Series User’s Guide
3
3
Serial Communication
SNAP PAC S-series controllers provide RS-232 and RS-485 communication as follows:
•
The
SNAP-PAC-S1
,
SNAP-PAC-S1-FM
, and
SNAP-PAC-S1-W
have two RS-232 serial ports
that support general-purpose communication with serial devices; you can send and receive
data from one or two serial devices connected directly to the controller. By default, Port 0 is set
to be connected to a modem using Point-to-Point Protocol (PPP) for creating TCP/IP networks
over serial or PSTN (Public Switched Telephone Network) lines. To connect Port 0 to serial
devices, change the port configuration in PAC Manager.
The S1 PACs also have one pluggable two-wire RS-485 port that can be used for SNAP PAC
SB-series serial brains and legacy Opto 22
mistic
™
I/O units, including the serial B3000 brain and
remote mistic bricks. The SNAP-PAC-S1-FM is Factory Mutual approved.
•
The
SNAP-PAC-S2
and
SNAP-PAC-S2-W
have four serial ports that can each be configured
using PAC Manager as either RS-232 or RS-485 (2-wire or 4-wire). These ports can be used for
either I/O or general-purpose serial communication. Configured as RS-232, the ports support
remote serial device communication, and any one of the ports can be configured as a PPP
modem connection. Configured as RS-485, the serial ports connect to SNAP PAC serial brains
and to
mistic
I/O units.
If you have a substantial number of serial I/O units, the PAC S2 is the controller to use. For the
default configuration settings of these ports, see
“Assigning Serial Ports on SNAP-PAC-S2
Controllers” on page 24
.
For additional serial interfaces, you can add one or more SNAP serial communication modules on
attached SNAP Ethernet-based I/O units.
I/O Unit Compatibility
The combination of Ethernet (both wired and wireless) and serial network interfaces gives SNAP PAC
S-series controllers the ability to control current and many legacy Opto 22 I/O units. All S1s have one
RS-485 port, and S2s can be configured with up to four.
The following table lists I/O units supported by S-series controllers:
S-Series Controller
On a Wireless LAN
On a Wired Ethernet Network
On a Serial Network
SNAP-PAC-S1
SNAP-PAC-S1-FM
SNAP-PAC-S2
---none---
SNAP-PAC-R1
SNAP-PAC-R1-FM
SNAP-PAC-R2
SNAP-PAC-R2-FM
SNAP-PAC-EB1
SNAP-PAC-EB1-FM
SNAP-PAC-EB2
SNAP-PAC-EB2-FM
SNAP-UP1-ADS*
SNAP-B3000-ENET*
SNAP-ENET-D64*
SNAP-ENET-S64*
SNAP-ENET-RTC*
SNAP-PAC-SB1
SNAP-PAC-SB2
B3000*
B3000-B*
SNAP-BRS*
B100*
B200*
G4D16R*
G4D32RS*
G4A8R*
SNAP-PAC-S1-W
SNAP-PAC-S2-W
SNAP-PAC-R1-W
SNAP-PAC-R2-W
SNAP-PAC-EB1-W
SNAP-PAC-EB2-W
* Legacy I/O processors; not recommended for new development
