DH Instruments COMPASS FOR MOLBOX, User Manual

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COMPASS

for molbox™ User’s Manual
© 1998-2003 DH Instruments, Inc .
Page 150
represent the physical connection of the device and an RS-232 port on the host computer or
the currently configured reference device.
Use the <Ref Com2> selection found at the end of the <COM Port> drop down list to access
the currently configured reference COM2 port rather than a standard communications port on
the host PC.
<Ref Com2> is usually COM2 of a molbox flow reference. If the reference
device does not have a valid COM2, COMPASS will generate an error when trying to access
the port. No special command setup is required to use the <Ref Com2> option. Select this
option just as any other COM port selection, COMPASS will set up the reference device
COM2 port and modify the commands as needed to send and receive commands using
this interface.
Figure 87. <RS232 Settings> Panel
13.4 IEEE-488 INTERFACE
IEEE-488, also known as GPIB (General Purpose Interface Bus), is a popular instrument
interface protocol. This interface allows a single IEEE-488 controller card to simultaneously interface with
up to 15 instruments. Each instrument must be set to an independent IEEE-488 address from 1 to 30.
The controller card also has an address that is used when multiple IEEE-488 cards are installed in the
PC. However, this is a rare case.
To use IEEE-488 with COMPASS , use the [Setup][System], <IEEE-488 Card> option to select the
IEEE-488 card installed in your PC (see Section 10.2). When this selection is made, no other card
related selections are required, only the instrument IEEE-488 address must be specified. Refer to the
instrument documentation for more information on how to determine the instrument IEEE-488 address.
13.5 DEVICENET INTERFACE
COMPASS supports National Instruments and SST DeviceNet interface cards. Select the card to use
with the [Setup][System], [DeviceNet Card] option (see Section 10.2). The command protocol as
outlined by the ODVA DeviceNet Specification is used by COMPASS to read and set flow. For this
reason, a remote command setup is not necessary. Output units and other settings within the device are
not changed. The DUT Definition must include the correct output range and unit information just like any
other DUT. The DeviceNet device MacID and baudrate are the only selections required to setup the
DeviceNet interface of a DUT.
13.6 [TOOLS], [REMOTE COMMUNICATIONS]
[Tools] , [Remote Communications] provides a simple means of sending individual command strings to
remote devices and receiving and displaying the response. This tool can be used for discreet remote
device communication and communications testing. Use this tool to familiarize yourself with the device’s
communications, for troubleshooting communications problems and determining the appropriate