Allen-Bradley A-B QUALITY DL20 Series User Manual page 115

Chapter 9
Installation and Maintenance
PARALLEL INPUT PORT
(Terminals 10 thru 23). The parallel input port accepts both commands and
variable data. Refer to Chapter 6 for more information.
MS1 MS0
(Terminals 20 and 21). These lines indicate whether the data on the input
lines is a message number or variable data.
ETS
(Terminals 10 and 11). The DL20 can be interfaced to multiplexed word
output modules via this input. When programmed properly, an edge or
voltage transition on this input causes data on the other parallel input
terminals to be read by the DL20.
Note: For use with non Allen-Bradley programmable controllers.
D9-D0
(Terminals 11A thru 19). Binary or BCD data on these lines is interpreted
either as a message number or as variable data.
+5VDC OUT
(Terminal 22). Use to apply an ON voltage to any of the parallel input signal
terminals (terminals 11A thru 21). Also use with Parallel Input Converters
(Catalog No. 2706-NG1, -NG2).
Important: Do not use for any other purpose.
GND
(Terminal 23.) Doubles as both a common reference for terminals 11A thru
22 and a shield ground.
AC PWR
(Terminal 26 thru 28.) The DL20 requires 85-264 VAC, 47-63 Hz. The
terminal marked E GND (terminal 28) must be connected to a reliable, low
impedance earth ground.
Note: The DL20 uses low voltage signaling on both the parallel and the
serial inputs. Any low voltage signals in a control panel are particularly
noise susceptible. Although the DL20 contains circuitry to filter noise,
reasonable precautions are necessary to ensure proper operation of the DL20.
The earth ground terminal (28) of the DL20 must be tied to a good earth
ground. Data input lines should be routed away from high energy wiring,
transformers, solenoids or coils, and devices known to generate large
amounts of EMI or RFI. Transient noise suppressors across solenoids, and
coils are often helpful in reducing interference.
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