Chapter
3
Remote Control of the LCR Meter
Remote Programming Reference
The Model Z9216 LCR meter may be controlled and programmed remotely using either an RS-232 or
the optional GPIB (IEEE488) interface. Any computer supporting either of these interfaces may be
used with the Model Z9216. Both interfaces are simultaneously active and are accessed via the
connectors on the rear panel. The Model Z9216 responds to commands from either interface and
returns answers to the interface from which the command came. All front and rear panel features
(except power) may be controlled.
Using the Interfaces
RS232 Interface
The RS232 interface specifies how to transfer data between a DTE, (data terminal equipment), device
such as a computer, and a DCE, (data communications equipment), device such as a modem. The
interface includes two signal lines that can be used for half-duplex (one-way) or full duplex
(simultaneous two-way) operation. Additional lines are used for controlling the flow of the data in the
sense that data cannot be transferred unless the appropriate flow control line is first asserted
(changed from 0 to 1).
The RS232 Interface Standard
The RS232 interface standard specifies a 25-pin connector as the standard interface in data
communications networks—a 25-pin D-SUB male connector at the DTE (data terminal equipment)
and a 25-pin D-SUB female connector at the DCE (data communications equipment)—with the pins
designated as shown in Table 3-1. The most common RS232 signals are the following:
Request to Send (RTS) and Clear to Send (CTS): The RTS signal line is asserted by the
computer to inform the modem that it wants to transmit data. If the modem decides that it is
read to receive data, it will assert the CTS line. Typically, once the computer asserts RTS, it
will wait for the modem to assert CTS before transmitting data.
Data Terminal Ready (DTR) and Data Set Ready (DSR): This line is asserted by the
computer to inform the modem that it is ready to receive data. In response, the modem will
assert DSR to indicate that it is turned on.
Carrier Detect (CD): This control line is asserted by the modem, informing the computer that it
has established a physical connection to another modem and is ready to transfer data.
In the application of the RS232 interface to the remote control of the LCR Meter, the meter plays the role of a
modem, and the flow of data is primarily measurements transmitted from the meter to the computer.
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