Cables; Minimum Three-Wire Interface With Software Protocol - HP 1652B Programming Reference Manual

Cables

Minimum
Three-Wire
Interface with
Software
Protocol
Note
Programming Over RS-232C
3-2
Selecting a cable for the RS-232C interface is dependent on your specific
application. The following paragraphs describe which lines of the
HP 1652B/53B are used to control the operation of the RS-232C relative
to the HP 1652B/53B. To locate the proper cable for your application,
refer to the reference manual for your controller. This manual should
address the exact method your controller uses to operate over the
RS-232C bus.
With a three-wire interface, the software (as compared to interface
hardware) controls the data flow between the HP 1652B/53B and the
controller. This provides a much simpler connection between devices
since you can ignore hardware handshake requirements. The
HP 1652B/53B uses the following connections on its RS-232C interface for
three-wire communication:
Pin 7 SGND (Signal Ground)
l
Pin 2 TD (Transmit Data from HP 1652B/53B)
l
Pin 3 RD (Receive Data into HP 1652B/53B)
l
The TD (Transmit Data) line from the HP 1652B/53B must connect to the
RD (Receive Data) line on the controller.'Likewise, the RD line from the
HP 1652B/53B must connect to the TD line on the controller. Internal
pull-up resistors in the HP 1652B/53B assure the DCD, DSR, and CIS
lines remain high when you are using a three-wire interface.
The three-wire interface provides no hardware means to control data flow
between the controller and the HP 1652B/53B. XON/OPP protocol is the
only means to control this data flow.
HP 16526/1663B