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:
30
SYMPTO
M…
POSSIBLE CAUSE
POSSIBLE FIX
Continuous
Flashing Green RUN LED…
Ethernet link was not established
Unit will flash green RUN LED and
maintain a solid STATUS LED at
startup until an Ethernet link has
been established.
Cannot Communicate…
Power ON to the unit?
Check if green RUN LED is ON?
Wrong IP Address
Change IP address of the unit or host
PC so they both match. Try the
default unit address of 128.1.1.100.
Many Communication Errors
…
Is cable segment longer than
100M?
Distance between two Ethernet
nodes is limited to 100 meters with
approved cable.
Correct Cable?
Shielded CAT-5/5E cable or
equivalent is recommended.
Missing earth ground connection.
Connect earth ground to TB3 GND
terminal adjacent to power terminal.
Inputs Not
Reading Back Correct OFF State…
Excitation is below 8V, or inputs
are tri-stated and floating.
The built-in wetting current sources
that function as input pull-ups are not
operable without proper excitation, or
with the inputs tri-stated. Connect an
excitation voltage, or pull the input
signal up above the 4.3V maximum
input threshold as required.
Unit Fails I/O Self Test…
Field wiring has been left
connected, one or more outputs
are turned ON, inputs are tri-
stated, excitation is not present, or
excitation is below 8V?
Do not float I/O as inputs must pull
above the 4V threshold in the OFF
state to read as OFF. Tri-stated
inputs float without an external
connection or with open-load
detection OFF
—do not tri-state inputs
prior to this test. I/O requires proper
excitation voltage (8-28V) to function.
Input Event Counters Are N
ot Working…
Are the Counting Inputs Enabled?
You must enable the counter inputs
either via the webpage or through the
Modbus registers (Reg: 40010).
Note
: 989EN-4C16 is not equipped
with Event Counters.
Are the Counting Inputs Stopped?
You must start the counters either via
the webpage or through the Modbus
registers (Reg: 40043).
Is your debounce time too long?
Set the debounce time to be less
than half of your input pulse width.
Excitation is below 8V, or inputs
are tri-stated and floating.
The built-in wetting current sources
that function as input pull-ups are not
operable without proper excitation, or
with the inputs tri-stated. Connect an
excitation voltage, or pull the input
signal up above the 4.3V maximum
input threshold as required.
TROUBLE-
SHOOTING
Diagnostics Table
…continued
