Hessen; Table 6-4: Rs-232 Communication Parameters For Hessen Protocol - Teledyne T802 Operation Manual

Section II Operating Instructions

6.5.2. HESSEN

Note The following sections describe the basics for setting up your instrument to
operate over a Hessen Protocol network. For more detailed information as
well as a list of host computer commands and examples of command and
response message syntax, download the Manual Addendum for Hessen
Protocol
api.com/manuals/.
6.5.2.1. HESSEN COM PORT CONFIGURATION
Note Make sure that the communication parameters of the host computer are also
properly set.
In addition, rather than issuing commands to the instrument in rapid
succession, bear in mind that the instrument software has a 200 ms latency
period before it responds to commands issued by the host computer.
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Teledyne API T802 Paramagnetic O
The Hessen protocol is a multidrop protocol, in which several remote instruments
are connected via a common communications channel to a host computer. The
remote instruments are regarded as slaves of the host computer. The remote
instruments are unaware that they are connected to a multidrop bus and never
initiate Hessen protocol messages. They only respond to commands from the
host computer and only when they receive a command containing their own
unique ID number.
The Hessen protocol is designed to accomplish two things: to obtain the status of
remote instruments, including the concentrations of all the gases measured; and to
place remote instruments into zero or span calibration or measure mode. API's
implementation supports both of these principal features.
The Hessen protocol is not well defined, therefore while API's application is
completely compatible with the protocol itself, it may be different from
implementations by other companies.
from the
Hessen protocol requires the communication parameters of the T802's COM
ports to be set differently than the standard configuration as shown in the table
below.
Table 6-4: RS-232 Communication Parameters for Hessen Protocol
PARAMETER
Baud Rate
Data Bits
Stop Bits
Parity
Duplex
To change the baud rate of the T802's COM ports, See Section 6.2.2.
To change the rest of the COM port parameters listed in the table above, see
Section 6.2 and Table 6-1.
Teledyne API web
STANDARD HESSEN
300 – 115200 1200
8 7
1 2
None Even
Full Half
Analyzer Operation Manual
2
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