Assigning a value to a read-only parameter will cause no fault, however the ACU will
overwrite this parameter immediately or some seconds later with the actual value.
7.2 The TCP/IP remote control interface
Controlling the ACU through the network is done by means of HTTP GET requests. Setting
parameter values or querying readings or settings, all is done by requesting HTTP documents
from the ACU. The message to the ACU thereby is coded into the URL as a CGI form parameter.
The ACU replies a one line document of the MIME type 'text/plain'.
The document name for remote control is /rmt , hence (assuming the ACU is listening to the IP
address 10.0.0.1), requesting a document with the URL
http://10.0.0.1/rmt?levl=?
Will let the ACU reply the actual beacon level in a one line text document:
levl=-52.31
This way all parameters may be queried or set, you may use your favorite web browser to try out
the remote control of the ACU manually.
7.3 The RS232 remote control interface
Beside the network interface, the ACU also provides an RS232 serial port which can be used to
control the device remotely. Depending on the device address set, the ACU either runs framed
protocol with start/stop characters and checksum or it provides a dumb terminal interface. The
RS232 interface always operates at 9600 baud, no parity, 8 data bits, one stop bit.
This interface is not yet implemented in the ACU19 and ACU-RMU! At these versions, you have to
select 'NONE' to enable the function of optional frontpanel display and keyboard. If another
setting is selected, an optional frontpanel and keyboard has no function.
If an address 'A' .. 'G' is selected, the ACU expects each message it receives to be packed into a
frame as described below.
char #
example
description
1
{
start character, always ' {'
2
A
device address (A..G)
3
l
first character of the message body
.
e
message body ...
.
v
..
.
l
..
.
=
..
n-1
?
last character of the message body
n .tc}
end character, always '} '
n+1
.
checksum
(C) 2022, SatService GmbH
www.satnms.com
ACU-ODM-UM-2209 Page 47/73
