Allen-Bradley 1746-BAS, User Manual, Page: 14 / 84

Publication 1746-UM004A-US-P
1-2 Module and Development Software Overview
Figure 1.1 Module with Door Open
Hardware Features
The module provides the following hardware features:
•
24K bytes of battery backed RAM for storage of user programs and data
•
capacitive backup of RAM during battery change
•
socket for a standard 1747-M1, M2, M3, or M4 memory module (1746-BAS)
for non-volatile storage of user programs
•
socket for a 1771-DBMEM1 or -DBMEM2 memory module (1746-BAS-T)
for non-volatile storage of user programs
•
battery-backed, 24-hour clock/calendar
•
free-running clock with 5 ms resolution
•
two isolated 9-pin D-shell serial ports (PRT1 and PRT2) that provide RS-232/
423, RS-422, and RS-485 communication with I/O devices
•
Port PRT2 provides DF1 full-duplex or half-duplex slave protocol for SCADA
applications
•
one RJ-45 port (DH485) that provides communication over the DH485
network
•
multiple LEDs for operator interface
•
SLC 500 backplane interface
PR T1
5
4
3
2
1
9
8
7
6
PR T2
5
4
3
2
1
9
8
7
6
DH485
BASIC
PR T1
5
4
3
2
1
9
8
7
6
PR T2
5
4
3
2
1
9
8
7
6
DH485
BASIC-T