.TH E1432_SET_INPUT_HIGH 3 E1432
.SH NAME
.nf
e1432_set_input_high \- Set source of input signal
e1432_get_input_high \- Get current source of input signal
.fi
.IX e1432_set_input_high(3) 3
.IX e1432_get_input_high(3) 3
.SH SYNOPSIS
.cS
SHORTSIZ16 e1432_set_input_high(E1432ID hw, SHORTSIZ16 ID,
                                SHORTSIZ16 high)
SHORTSIZ16 e1432_get_input_high(E1432ID hw, SHORTSIZ16 ID,
                                SHORTSIZ16 *high)
.cE
.SH DESCRIPTION

\fIe1432_set_input_high\fR sets the input to the ADC, of a single
channel or group of channels \fIID\fR, to the value given in
\fIhigh\fR.

\fIe1432_get_input_high\fR returns the current input high selection,
of a single channel or group of channels \fIID\fR, into a memory
location pointed to by \fIhigh\fR.

\fIhw\fR must be the result of a successful call to
\fIe1432_assign_channel_numbers\fR, and specifies the group of
hardware to talk to.

\fIID\fR is either the ID of a group of channels that was obtained with a
call to \fIe1432_create_channel_group\fR, or the ID of a single channel.

\fIhigh\fR controls the analog input to the input channel.
\fBE1432_INPUT_HIGH_NORMAL\fR selects the front panel connector.
\fBE1432_INPUT_HIGH_GROUNDED\fR grounds the input.
\fBE1432_INPUT_HIGH_CALIN\fR selects the module's CALIN line.
\fBE1432_INPUT_HIGH_BOB_CALIN\fR selects the module's CALIN line via
the cal connection in a break-out box.
\fBE1432_INPUT_HIGH_CALOUT\fR is the same as
\fBE1432_INPUT_HIGH_NORMAL\fR, except that the input is also connected
to the module's CALOUT line.

For backwards compatibility with the E1431 host interface library, the
following obsolete values for \fIhigh\fR are also accepted:
\fBE1432_INPUT_SOURCE_BNC\fR, which is the same as
\fBE1432_INPUT_HIGH_NORMAL\fR; \fBE1432_INPUT_SOURCE_SUMBUS\fR, which
is the same as \fBE1432_INPUT_HIGH_CALIN\fR; and
\fBE1432_INPUT_SOURCE_ZERO\fR, which is the same as
\fBE1432_INPUT_HIGH_GROUNDED\fR.

On input channels, only \fBNORMAL\fR, \fBGROUNDED\fR, \fBCALIN\fR, and
\fBBOB_CALIN\fR are supported.  The \fBBOB_CALIN\fR value is valid
only when a smart break-out box (such as a Charge Break-out Box or
Microphone Break-out Box) is connected to the input.

On tach channels, only \fBNORMAL\fR and \fBCALOUT\fR are supported.
The \fBCALOUT\fR setting can be used to monitor the analog signal
connected to a tach input.  To do this, the module's CALOUT line must
be connected back to the module's CALIN line, using
\fIe1432_set_calin\fR.  In addition, an input channel must be told to
monitor the CALIN line by using \fIe1432_set_input_high\fR on the
input channel.  Then the data collected by the input channel will show
the signal on the tach input.  Because there is only one CALOUT line,
only one tach channel may drive the CALOUT line at any one time.

It is also possible to set up a tach channel to drive the VXI sumbus,
and have the sumbus drive CALIN, and have an input channel monitor
CALIN.  This allows an input channel to monitor a tach channel from a
different E1432 module, but results in a larger DC offset error and
more noise.  To make this work properly, pass
\fBE1432_CALIN_SUMBUS_TACH\fR (not \fBE1432_CALIN_SUMBUS\fR) to
\fIe1432_set_calin\fR, to ensure that the input channel can figure out
the correct scale factor.

When monitoring tach signals via the CALIN line using either of the
above methods, the tach signal bypasses most of the input range
setting hardware.  Because of this, the tach signal level that can be
monitored is limited.

On an E1432 51.2 kHz input SCA, the maximum tach signal level when the
tach trigger level is zero is about 6 volts.  On an E1433 196 kHz
input SCA, the maximum tach signal level when the tach trigger level
is zero is about 2 volts.  If the tach trigger level is larger than
+-4.9 volts, then the tach board attenuates the tach signal, resulting
in a five times greater range that can be monitored (30 volts for
E1432, 10 volts for E1433).

This parameter is not used for source channels.
.SH "RESET VALUE"
After a reset, \fIhigh\fR is set to \fBE1432_INPUT_HIGH_NORMAL\fR.
.SH "RETURN VALUE"
Return 0 if successful, a (negative) error number otherwise.
.SH "SEE ALSO"
.na
e1432_get_scale, e1432_set_analog_input, e1432_set_calin
.ad
