BusWorks® 961/962EN User’s Manual Modbus TCP/IP Differential I/V Input
__________________________________________________________________
_______________________________________________________________________________________
Acromag, Inc. Tel:248-624-1541 Fax:248-624-9234 Email:
http://www.acromag.com
12
This module includes special messaging functionality (i2o, input-to-output
communication) that allows it to send its input level to an output channel on
an Acromag 972EN-400x or 973EN-400x analog output module. The I/O
Mapping page is used to specify the static IP address of the 972/973EN
module to send an input channel’s data to, the specific Holding Register
address of that module, and an update rate.
IMPORTANT:
This module is designed to function as a Modbus TCP/IP
slave/server. Normally, Modbus servers are not allowed to initiate messages
on their own and may only respond to client/master requests. The I/O
mapping function is a special application that may cause confusion for
master/client devices linked to the same network. Other master devices
should be restricted from attempting to control i2o target devices.
Each input channel of this device may be mapped to one or two output
channels of Acromag 972EN-400x (current output), or 973EN-400x (voltage
output) modules. The output channel that is to be controlled in this manner
is determined by the Map-To Holding Register address specified. The data
written will be in identical percent-of-span units with no rescaling.
Subsequent messages will be sent at a periodic rate specified via the update
time. Note that the target output channels may still be controlled
independently, but their level will be overwritten by subsequent mapped
messages when enabled.
Use the scroll bar on the right to scroll down to the bottom of this screen as
shown on the following page.
The I/O Mapping Page of model 962EN-4006 is slightly different than the
961EN-4006 as it requires that the mapping method be selected. That is,
the 962EN input signal range is bipolar and you must additionally select
whether the mapping is to be bipolar (0V input maps to 50% output), or
unipolar (0V input maps to 0% output). You can map each input channel to
one or two analog output channels of another 972EN or 973EN module.
WEB BROWSER
I/O Mapping Page
(Optional i2o Function)
This messaging function works
best if the target module(s) are
already online and ready to
receive messages. It will still
work if the target output
modules come online after the
input module, but may take
several minutes to “discover”
all the network targets and
begin transmitting to them.
If the input module or the
target module(s) go offline,
remote messaging will resume
on its own when the
connection is re-established,
but this “healing” function may
take several minutes
depending on which device(s)
went offline, why, and for how
long.
Note:
Remote messaging
may only be configured via the
built-in web browser page as
there are no Modbus registers
for specifying these
parameters.
The actual data written to the
analog output is in percent-of-
span units represented by a
16-bit signed integer value
with resolution of 0.005%/lsb.
The possible range is –
163.84% (-32768 decimal) to
+163.835% (+32767 decimal).
For example, -100%, 0% &
+100% will be represented by
the decimal values –20000, 0,
and 20000, respectively. Input
data may not be rescaled.
