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1620A "DewK" Thermo-hygrometer
User's Guide
8.1.2
8.1.3
8.1.4
70
RF Wireless (optional)
The RF wireless interface allows the instrument to receive and respond to com-
mands from a remote computer through a radio-frequency wireless link. The
computer must be attached to an RS-232 or USB RF modem. See Section 5.8,
Accessories, for more information. These accessories can be purchased sepa-
rately. In the case of a USB RF modem, USB driver software supplied with the
modem maps the wireless link to a virtual COM port on the computer. Proper
communication between the instrument and a computer's RF modem requires
that both be set with matched settings, as explained in Section 7.5.3.2.
The RF interface uses the 802.15.4 standard (which is the basis for the ZigBee).
It operates in the license-free 2.4 GHz frequency band, with a very low trans-
mission power of 1 mW. Typical unobstructed range is 100 ft. (30 m). The
range might be reduced if RF-reflecting walls, obstructions, or interfering elec-
tronic equipment are nearby. Some channel numbers might work over farther
ranges than others.
LAN
The LAN interface allows the instrument to receive and respond to commands
from a remote computer over an Ethernet IP network. Redirector software can
be installed on a computer to map the TCP/IP link to a virtual COM port. Com-
munications uses TCP port 10001. Windows® Hyperterminal may also be
used. The settings for configuring and operating the LAN interface are ex-
plained in Section 7.5.3.3. Commands that might change operating settings can
only be used if the COMMAND setting is ON.
The LAN interface operates on either a 10Base-T or 100Base-TX Ethernet IP
network. A CAT 5 Ethernet cable attaches to the thermo-hygrometer readout at
the RJ45 socket on the left side of the instrument. The RJ45 socket has two
LED indicators. The bottom LED indicates link state: off for no connection,
amber for 10 Mbps, and green for 100 Mbps. The top LED indicates link activ-
ity: off for no activity, amber for half duplex, and green for full duplex.
Command Syntax
The thermo-hygrometer readout accepts commands that set parameters, execute
functions or respond with requested data. These commands are in the form of
strings of ASCII-encoded characters. As far as possible, the thermo-hygrometer
readout conforms to SCPI-1994. One notable exception is that compound com-
mands are not allowed as explained below.
Commands consist of a command header and, if necessary, parameter data. All
commands must be terminated with either a carriage return (ASCII 0D hex, 13
decimal) or new line character (ASCII 0A hex, 10 decimal).
Command headers consist of one or more mnemonics separated by colons (:).
Mnemonics may use letter characters, the underscore character (_), and possi-
bly numeric digits as well. Commands are not case sensitive. Mnemonics often
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