BusWorks® Model 989EN U
ser’s Manual Modbus TCP/IP Digital I/O & Counters
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Acromag, Inc. Tel:248-295-0880 Fax:248-624-9234 Email:
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Built-In Self-Test for Port I/O Read/Write
–
Useful for troubleshooting
I/O and internal communications for diagnostic purposes.
•
Built-in Output Thermal, Over-Current, & Over-Voltage Protection -
Inputs also include thermal protection. Status flags report these faults.
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Inputs May Be Optionally Tri-Stated
– The inputs may be tri-stated to
a high-impedance state (disables wetting current). Tri-stated inputs act
as simple comparators with a 4.0V threshold.
•
Outputs Include Selectable Fast Short-Fault Protection
–
By default,
if an output drives a shorted load, built-in thermal protection will kick-in to
protect the output. Optionally, this device allows you to specify whether
a port is to rely on the internal thermal protection mechanism, or
implement a faster responding 100-450us shutdown mechanism based
on the output drain-to-source voltage. This effectively allows output port
protection to be tailored to incandescent lamp loads, or inductive loads.
Limiting thermal stresses also helps preserve the life of the output driver.
•
Failsafe Mode Support w/Watchdog Time Control
– Outputs can be
sent to a failsafe state if the host fails and a watchdog timeout occurs.
•
Output Open-Load Detect
– Outputs include 50uA current sinks (pull-
downs) that can be enabled to flag an open load with inputs tri-stated.
•
Internal Watchdog
- A hardware watchdog timer is built into the
microcontroller that causes it to initiate a self reset if the controller ever
“locks up” or fails to return from an operation in a timely manner.
•
Wide-Range DC-Power
– Wide range diode-coupled power for use with
redundant supplies, and/or battery back-up.
•
Hardened For Harsh Environments
- For protection from RFI, EMI,
ESD, EFT, and surges. Has low radiated emissions per CE
requirements.
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Wide Ambient Operation
– Reliable over a wide temperature range.
The 989EN digital I/O module will interface with any mix of up to sixteen
digital input and/or output signals, and provide an isolated 10/100Mbps
Ethernet interface for configuration, monitoring, and control of the I/O.
Inputs and outputs are connected in tandem with each other. An internal
microcontroller will switch outputs ON/OFF and sample the digital inputs.
The eight 32-bit event counters capture signals up to 150 Hz, and include a
programmed debounce, selectable up/down counting, selectable edge, and
eight alarm outputs managed by the microcontroller (
available on the
989EN-4016 model only
). Input counts and configuration parameters are
stored in non-volatile memory. With outputs turned OFF, channels operate
either as active-low, wide-range voltage inputs or up to eight event counters.
Otherwise, inputs monitor the state of the corresponding open-drain output
for independent “loop-back” monitoring of the output.
Outputs of these models are the open-drains of n-channel mosfets (low-side
switches). Inputs are active-low. A buffered input comparator is connected
in tandem with each drain circuit and compares this signal to a 4.0V
reference voltage. Inputs sense switch closure via built-in wetting current
generators (2mA). These current sources can initially provide a higher level
of current during switch closure (16mA). This helps to minimize oxide
buildup on external switch contacts. These sources also eliminate the need
to pull-up the tandem open-drain mosfets of the output circuitry. Optionally,
these current sources can be disabled and the input will operate as a simple
high-impedance comparator with a 4.0V threshold.
KEY FEATURES
HOW IT WORKS