Cannon TE-3000, Инструкция по эксплуатации

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CANNON
® TE-3000 Thermoelectric Constant Temperature Bath
Version 1.1c — May, 2005;
CANNON
® Instrument Company
2139 High Tech Road • State College, PA 16803 • USA
C. Half duplex and polled (multi-drop) operations
The RS-485 interface is provided to permit a network connection from
one computer to multiple instruments. A three-wire (with feed-through)
screw terminal connector is furnished on the rear panel of the TE-3000
which allows the use of any three conductor cable (two wire shielded,
preferred) to be connected into and out of the instrument. The computer
must have an RS-232 to RS-485 adaptor plugged into the computer serial
port.
Network capability The network is capable of supporting up to 16 instruments at distances of
up to 4000 feet. If the network is configured for more than three occu-
pants and/or if the network spans a long distance (>100 feet) then it may
be required that termination resistors be added to the first and last occu-
pant on the network. Contact
CANNON
®
Instrument Company for
further assistance about the configuration of your particular network
needs.
For a complete description of the Commands, Queries, Responses, and
Reports on this interface, please refer to section D which follows.
D. Commands, queries, responses and reports
The protocol on the serial interfaces includes commands and queries
which are sent by a master controlling computer, and responses which are
sent by the TE-3000 in reply to every command or query it receives. The
TE-3000 may also issue timed interval reports automatically if it is
configured to operate in the point-to-point mode. If the TE-3000 is
configured to operate in the multi-drop mode, reports will only be issued
in response to a specific query.
Protocol
All Commands and Queries sent to the TE-3000, regardless of which
interface , must be preceded by a / and a # . The # is the selected address
(rear address switch) of the TE-3000 and must be
0-9
or
A-F
while the
/
is a simple slash character denoting the beginning of an addressed
command or query.
All Commands must then be identified with the letter C and all Queries
must be identified with the letter
Q
. Commands and Queries have various
types which are always defined with two letters -
$$
. Some command
and query types have arguments which may be associated with it to
further define the action which must be taken -
&..& .
And finally, all Commands and Queries must end with a carriage return
(
R
).