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:
35
+
(5.5V MIN)
OFF
+3.3V
+3.3V
3.3V RAIL
8
5
RJ45
2
18-36VDC
(5V MIN)
STATUS
LED
CLK
POWER
LED
PUSH
BUTTON
SWITCH
LINK
LED
3.3V
6
7
3
1
4
DC-
PGM
PORT
CLK
25MHz
P
O
W
E
R
25MHz
ON
+3.3V
+3.3V
+3.3V
DC+
SIMPLIFIED SCHEMATIC
(1 CHANNEL)
16 CHANNELS TOTAL
RTN
I/O
EXC
OPEN-DRAIN
OUTPUT
BUFFERED
INPUT
DE FA
MICROCONTROLLER
ACTIVITY LED
ISOLATED
DC/DC
CONVERTER
GND
Ethernet Port Includes
ESD Protection
ISOLATED ETHERNET
Active
Low
ETHERNET
MAC/PHY
ENCLOSURE IS COMMON
TO EARTH GROUND
ISOLATED INPUT POWER
INPUT DETECTOR
SIMPLIFIED I/O CIRCUIT
(SINGLE CHANNEL)
OUTPUT CONTROLLER
THE ENCLOSURE IS COMMON TO EARTH GROUND.
EARTH GROUND IS ISOLATED.
989EN SIMPLIFIED SCHEMATIC
THERE ARE SIXTEEN DIGITAL I/O CHANNELS AND FOUR RTN
TERMINALS. ALL PORTS SHARE COMMON RETURN.
The I/O terminals and the Ethernet port terminals also include transient
suppression. An internal microcontroller will switch outputs ON/OFF and
sample the digital inputs. Embedded configuration parameters are stored in
non-volatile memory integrated within the micro-controller. A wide-input,
high-efficiency, DC to DC converter provides isolated power to the unit.
Most I/O power is actually derived from the excitation supply, requiring
excitation to be present to operate the I/O. Refer to the simplified schematic
on the following page to help gain a better understanding of circuit operation.
There are 16 I/O channels across 4 terminal blocks. All I/O terminals
include transient suppression. The I/O circuitry has built in thermal, over-
voltage, and over-current protection. The excitation terminal also has built-in
transient and reverse polarity protection.
HOW IT WORKS
