11
User Manual
MN032EN
Effective October 2017
215U-2 802.11
wireless I/O and gateway
EATON
www.eaton.com
Figure 19. Single-ended voltage inputs
Analog outputs
The 215U-2 module provides two 0–24 mA DC analog outputs for
connecting to analog inputs on equipment (such as PLCs, DCS, and
loggers) or connecting to instrument indicators for displaying remote
analog measurements. The 215U-2 analog outputs are a sourcing
output and should be connected from the analog output terminal
through the device or indicator to ground (GND). See
Figure 20
for
connections. The LEDs provide level indication depending on current.
The LEDs appear dimmed for 4 mA and bright for 20 mA.
Figure 20. Analog outputs
System design
Design for failures
All well-designed systems consider system failure. I/O systems
operating on a wire link will fail eventually. Failures can be short-
term, such as interference on the radio channel or power supply
failure, or long-term, such as equipment failure.
The modules provide the following features for system failure:
•
Outputs can reset if they do not receive a message within a
configured time. If an output should receive an update or change
message every 10 minutes and it has not received a message
within this time, some form of failure is likely. If the output
is controlling machinery, it is good design to switch off the
equipment until communications are re-established.
•
The modules provide a fail-safe feature for outputs. This is a
configurable time value for each output. If a message has not
been received for this output within the configured time, the
output will assume a configured value. We suggest that this reset
time be a little more than twice the update time of the input. It
is possible to miss one update message because of short-term
interference. However, if two successive update messages are
missed, long term failure is likely and the output should be reset.
For example, if the input update time is three minutes, set the
output reset time to seven minutes.
•
A module can provide an output that activates on communication
failure to another module. This can be used to provide an external
alarm indicating that there is a system fault.
Testing and commissioning
We recommend that the system is fully bench tested before
installation. It is much easier to find configuration problems on
the bench when the modules are next to each other as opposed
to being miles apart. When the system is configured and you are
confident that it works, back up the configurations of all modules.
