DH Instruments MFC SWITCHBOX, User Manual

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MFC SWITCHBOX USER’S MANUAL
© 1997-2008 DH Instruments, a Fluke Company Page 8
When the selected channel is associated with a ‘measure’ profile type, the control signal is sent to the
device on channel 1. This setpoint must be set in voltage and will set flows according to the range
specified in the profile for the device connected to channel 1. The measurements will be taken from the
selected channel using the profile associated with the selected channel to define the flow value.
If the profile for channel 1 indicates a current based MFC, then attempting to select a channel with a
‘measure’ profile type will result in the error message <Voltage mode needed on channel 1 control>.
Pressing the [ð] arrow key any time the MFC control function is active causes an instant display of
the current MFC profile summary allowing a quick check of the characteristics of the currently active
MFC profile. Pressing [ESCAPE] returns from MFC profile screen to the last run screen.
3.3 MFC PROFILES
MFC profiles are used by molbox1 or MFC-CB to configure the MFC function. MFC profiles define the
analog signal range of the MFC or MFM and the relationship between the analog signal range and the
flow range of the MFC or MFM. This information allows molbox1 or MFC-CB to operate with the correct
signal for the selected MFC and to convert the MFC or MFM analog signals to the corresponding flow or
% FS values, when desired.
MFC profiles are set up using [SETUP] , <1MFC> . MFC profiles are stored by molbox1 and MFC-CB
under profile numbers. This is the same number that will be used to select the MFC profile when the
MFC function is activated using the MFC function key. Up to 26 MFC profiles can be defined and stored.
MFC profiles are designed to allow the user to set up the profiles of the MFCs that are typically used with
so that they can be conveniently recalled from a lookup table when needed.
MFC profiles #1 and #2 are default profiles for working with the MFC function directly in analog units
without an MFC flow range or units. Profile #1 is 0 to 5 V, Profile #2 is 4 to 20 mA. When the MFC
function is active with Profile #1 or #2 selected, the MFC units of measure will always be V or mA.
The UNIT function selects the molbox1 flow measurement unit.
3.4 UNITS OF MEASURE
When using the MFC Switchbox with molbox1
When the MFC function is active, the molbox1 flow units of measure will always be the units of measure
specified in the active MFC profile.
When the MFC function is active, the [UNIT] function key is for selection of the units of measure for the MFC
setpoint and output. The choices available are <V> or <mA> (depending on the active MFC profile's analog
range), % FS or flow. The % FS selection will cause MFC setpoint and output to be displayed in % FS of the
MFC which molbox1 will calculate using the definition of analog range and flow range contained in the MFC
profile. The
<3flow> selection will cause MFC setpoint and output to be displayed in the flow units of the
MFC using the definition of analog range, flow range and flow units contained in the MFC profile.
When using the MFC Switchbox with MFC-CB
Units of measure are set using [UNIT] . If MFC profile #1 or #2 is active, the only units available are V,
mA or % FS. If an MFC profile that specifies a flow range (any profile >#2) is selected, the display unit of
measure may be a flow unit. See the MFC-CB Operation and Maintenance Manual for additional information.