Serial Interface Manual
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TLS2 Monitoring Systems
Part No. 577013-767, Revision H
7
7.0
FUNCTION CODES AND RESPONSE MESSAGES
The function codes and data fields of the message formats are described in this section.
Most response messages can be requested for either a single device (tank, etc.) or all devices. A "TT" in
the function code signifies single device number 01 through 16. When "TT" is 00, it signifies all
devices.
Typically, response messages include information on the active devices only. That is, those devices that
are connected and working. However, the system can be forced to send data on inactive devices by
using an inactive device number. In this case, if no valid data is available on a device, the message is
filled out with question marks (?) in the place of numbers.
Computer format response messages do not include any formatting characters such as carriage returns,
line feeds, spaces, nulls, labels, etc. Only those characters shown are actually included in the response
message. For convenience, the messages are shown in segments and do not actually include any line
feeds, carriage returns, etc. Also, the notes to the right and between the message lines are not included
in the messages. All number values contained in the response messages retain leading zeroes.
Display format response messages include the formatting characters shown. All message lines end with
a carriage return, line feed, and six nulls. All response messages start and end with at least one blank
line.
The system function codes and response messages are described in detail in the following sections. A
summary list of all function codes is given at the end of this document.
