4. REMOTE OPERATION
Page 95
© 1998-2007 DH Instruments, a Fluke Company
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4.1
OVERVIEW
Most of the molbox RFM’s front panel functions can also be executed by commands from a
remote computer. The host computer can communicate with the molbox RFM using the molbox RFM
COM1 RS232 port or the IEEE-488 port. The command syntax is the same for either port except when
using the IEEE STD. 488.2 Common Commands.
4.2
INTERFACING
Sending a command to the molbox RFM will place it into remote mode. The remote indicator in the lower
right hand corner of the molbox RFM front panel will light when the molbox RFM is in remote mode. It will
also flicker when a command is received. The menus usually accessed from the front panel are locked-
out while in remote. The
[P&T]
key will still respond to allow the user to change the data being viewed
while the molbox RFM is in remote mode. Pressing the
[ESCAPE]
key will return the molbox RFM to
local operation unless the “REMOTE” command was sent to the unit, which locks out keypad operation
until the “LOCAL” command is sent.
Most remote commands will return a reply within 500 ms. You
must
wait for this reply before issuing
another command to the molbox. This ensures that the molbox RFM has completed the command.
An exception to this is the use of any of the IEEE STD. 488.2 Common Commands (see Section 4.3.4.1)
via the IEEE-488 interface (common commands all start with an asterisk, “*”). The common commands
only generate a reply if using the COM1 port or if the query form of the common command is used
(command followed by a “?”).
The following commands take more than 500 ms to reply:
ALLR, DP, FR, PR, RATE, SR, TARE
Up to 2 seconds to allow a new measurement.
GAS
Up to 5 seconds to complete a change.
TARESET, DEVICE=EXT, RESET
Up to 10 seconds to complete.
LabVIEW drivers are available for the molbox RFM. These drivers allow users of the National
Instruments’ LabVIEW environment to create systems that include one or more molbox RFMs using
LabVIEW virtual instruments instead of using the remote commands directly. The molbox RFM
LabVIEW drivers are an abstraction of the remote commands into a consistent set of common and
specific instrument functions. The drivers can be obtained at NO charge from the DHI worldwide
web site, www.dhinstruments.com.
