Acromag Bus Works 900EN Series, User Manual

Page: 12 / 67

BusWorks® Model 989EN U
ser’s Manual Modbus TCP/IP Digital I/O & Counters
_________________________________________________________________________________
_______________________________________________________________________________________
Acromag, Inc. Tel:248-295-0880 Fax:248-624-9234 Email:
sales@acromag.com http://www.acromag.com
11
✓
Connect your output load to the output terminals as shown below.
A
B ON
V
V
D
EXT
EXC
D L
TB3
OFF
ON
V
0-28V
8-28V
L
A
OFF
RTN
TB1
CH03
CH02
CH01
CH00
FOR EVEN GREATER OUTPUT DRIVE,
CONNECT AN INTERPOSING RELAY.
NOTE: IT IS ACCEPTABLE TO UTILIZE DC POWER TO THE UNIT
TO ALSO DRIVE THE EXCITATION TERMINAL AND/OR THE LOAD.
EXCITATION IS REQUIRED. EXTERNAL EXCITATION IS 8V TO 31V MAX.
OUTPUTS MAY TEMPORARILY SHUT DOWN FOR EXCITATION OVER VOLTAGES ABOVE 28V.
DIGITAL OUTPUT CONNECTIONS
Note - You must connect port excitation to operate I/O. Your excitation
voltage should be greater than your load voltage. Outputs may temporarily
shut down for excitation voltages over 28V, or load voltages greater than
31V.
IMPORTANT
– Add Protection With Inductive Loads:
Outputs should
include reverse-bias shunt diodes to help protect the output switch from
damage due to the high reverse-bias voltages normally generated when
switching inductive loads. You should add external protection near the
inductive load to prevent these transients from being sent along the
connection wires. Place a diode (1N4006 or equivalent) across an inductive
load with the cathode to (+) and the anode to (-).
LOAD GROUNDING:
If your load is connected at some distance from the
unit, or your load currents are high, earth grounding the return lead should
be done local to the I/O terminals to allow the built-in transient protection to
effectively shunt to earth via a low impedance path not affected by IR losses.
Refer to the examples below for other types of output connections.
R
I/O
EXT
EXC
LED
EXC
ON
SSR
V
8-28V
RTN
OFF
(N.O.)
TO
LOAD/LINE
TO
LOAD/LINE
OPEN-DRAIN OUTPUTS SHARE RETURN.
EXCITATION IS REQUIRED. EXTERNAL EXCITATION IS 8V MIN TO 31V MAX.
SOLID-STATE RELAY (SSR) OR LED DRIVER CONNECTIONS
CONNECTIONS
Digital Outputs
Outputs are the open-drains of
mosfet switches and are
intended for DC current-
sinking applications only.
Note: Outputs will turn OFF
(open) following a software
reset or power interruption to
the unit.
Do NOT connect outputs to
voltages greater than 31V or
damage to the I/O port may
result. The 31V limit is the
working voltage limit of the
built-in transient voltage
suppressors at each I/O
channel.
Solid-State Relay (SSR) or
LED Driver
You should also consider
whether open-load detection
feature should be enabled, as
this can pull 50uA of drive
current through the load in the
OFF state.