Allen-Bradley A-B QUALITY DL20 Series User Manual page 113

Chapter 9
Installation and Maintenance
9–2
Wiring Procedures
Refer to Figure 9.1 for wiring terminal descriptions. The procedures
described below and the wiring terminal diagram guides you through the
wiring process.
1. Connect an 85-264 VAC, 47-63 Hz input voltage source to terminals 26,
27, and 28 of the DL20. The voltage source must have 15 amp (max)
short circuit protection.
ATTENTION: Terminal 28 (E. GND) must be connected to a
reliable low impedance earth ground to protect the display from
!
electrical noise. This ground connection will also protect
personnel from electrical shock if the electronics short to the
DL20 case.
Do not turn on power to the display until all other wiring to the serial or
parallel ports is completed.
2. Connect communication lines from the host programmable controller or
computer as well as peripheral equipment to the serial or parallel ports of
the DL20. Refer to Figures 9.2 through 9.12.
ATTENTION: The DL20 has simplex (single direction)
communication only. Only use the DL20 for non-critical display
!
applications. Simplex communication provides no ACK/NAK
(duplex) verification that messages sent by the programmable
controller or computer have been received and displayed.
The data format for the RS-232 and RS-422 ports is identical. It is very
important that the communication parameters of the DL20 and the connected
device are the same.
Baud rate: 300, 1200, or 9600
Data length: 8 bits (including parity if any)
Parity: odd, even, or none
Stop bits: 1
Use terminal 9 on the DL20 (+12 VDC OUT) to tie RS-232 handshake lines
high if necessary. Do not use terminal 9 for any other purpose.