Contrec 515, Operation Manual

Page: 64 / 92

Communications
56 515 HC04 - 8 June 2007
Simple ASCII Protocol
This simple ASCII protocol requires that all requests are initiated with a
colon (:) and terminated with a carriage return (
C
R
). The message
termination can include a linefeed before the carriage-return (
L
F
C
R
), but it
is the carriage-return that acts as the message termination.
All responses by the instrument are terminated with a linefeed and a
carriage-return (
L
F
C
R
).
Requests Format
The format of a request to the instrument is as follows:
Each request must include the address and command portions. The
underlined section is an optional part of the request string.
Address
In multipoint communications, each instrument must have a unique address
and it is essential in the request for identifying a particular instrument.
However, it may be set to 000, for special broadcast commands.
For single-instrument communications, the address can also be set to 000 in
the request.
Refer to Communications on page 43 for setting the instrument address.
Note: The instrument always responds with its address in the header
regardless of the type of request.
Log Type and Number
The log type and number enables a communicating device to retrieve data
from the instrument. The data can be from timebased and/or event-based
logs. Data can also be from the current process variables with the either
accumulated or non-accumulated (resettable) totals.
All logged records of the process variables contain the accumulated totals.
The log request is optional. If the log request is not included, or the log
number is set to 000, the instrument returns the current process variables. If
the log request is included, the log number defines the specific log entry by
counting backwards. The most recent log entry for a timebase is 001.
:A001:LR001:XXX?
L
F
C
R
Address Log Command Log
type number
Carriage-return
Linefeed