Advanced Measurement Technology 273A, Руководство пользователя

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Model 273A Potentiostat/Galvanostat User’s Manual
A.5. RS 232C Interface
PIN FUNCTION COMMENT
1 Earth Ground Ties the chassis of the 273A to that of the computer.
2 Transmit The 273A transmits on this line. It must connect to the computer connector
Data pin that receives serial data.
3 Receive Data The 273A receives data on this line. It must connect to the computer
connector pin that transmits serial data.
4 Request to This line is permanently asserted in the 273A, that is, it is always at a positive
Send logic level ( +12 V). As a result, the computer continuously receives the
message that the Model 273A is ready to receive a character.
5 Clear to Send The computer controls the 273A via this line. To enable the 273A to transmit,
the line is placed at the positive logic level (+3 V to +12 V). To hold off
transmission by the 273A, the line must be at the negative logic level (-3 V to
-I2 V). Once this line goes positive, data transfer, if initiated by an appropriate
command, will proceed rapidly. This line is pulled up to + 12 volts so that, if it
is left unconnected, the 273A is allowed unimpeded transmission.
6 Unused
7 Logic Ground Data signal levels should be with reference to logic ground. The logic ground
line of the 273A should interconnect with the logic ground line of the
computer.
8 -10 Unused
11 +5 V 5 V (100 mA max) is needed by the connected apparatus, don't
connect to this pin. In no case should this +5 V level be tied to the +5 V level
in the computer. +5 V can be used to continuously assert the Clear-to-Send
Line (pin 5), allowing the 273A to transmit at any time.
18 +12 V
20 +12 V +12 V (300 in series)
25 -12 V
Note that the 273A RS-232C port is configured as a female DTE port (Data Terminal Equipment) rather
than as a DCE (Data Communications Equipment). Thus, cabling to most microcomputers can be
accomplished with a standard reversed or switched RS-232C cable, also known as a null modem cable.