.TH E1432_SET_INPUT_LOW 3 E1432
.SH NAME
.nf
e1432_set_input_low \- Set grounding mode of input signal
e1432_get_input_low \- Get grounding mode of input signal
.fi
.IX e1432_set_input_low(3) 3
.IX e1432_get_input_low(3) 3
.SH SYNOPSIS
.cS
SHORTSIZ16 e1432_set_input_low(E1432ID hw, SHORTSIZ16 ID,
                                SHORTSIZ16 low)
SHORTSIZ16 e1432_get_input_low(E1432ID hw, SHORTSIZ16 ID,
                                SHORTSIZ16 *low)
.cE
.SH DESCRIPTION

\fIe1432_set_input_low\fR sets the grounding mode, of a single channel
or group of channels \fIID\fR, to the value given in \fIlow\fR.

\fIe1432_get_input_low\fR returns the current input low selection,
of a single channel or group of channels \fIID\fR, into a memory
location pointed to by \fIlow\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.

\fIlow\fR controls the analog input to the input channel.
\fBE1432_INPUT_LOW_GROUNDED\fR grounds the low-side of the channel.
\fBE1432_INPUT_LOW_FLOATING\fR lets the low-side of the channel float,
making the input a differential input.

For backwards compatibility with the E1431 host interface library, the
following obsolete values for \fIlow\fR are also accepted:
\fBE1432_INPUT_GROUNDED\fR, which is the same as
\fBE1432_INPUT_LOW_GROUNDED\fR; and \fBE1432_INPUT_FLOATING\fR, which
is the same as \fBE1432_INPUT_LOW_FLOATING\fR.

Only input channels support the setting the grounding mode - source
and tach channels are never floating, and are always grounded.

If a "smart" break-out box is attached to the channel, such as the
E3242A Charge break-out box or the E3243A Microphone break-out box,
then this function will tell the break-out box to set the grounding
appropriately.

However, if a passive break-out box is attached (or no break-out box),
there is no way to tell the break-out box what grounding to use, nor
is there any way to ask the break-out box what the current grounding
mode is.  In this case, the parameter to \fIe1432_set_input_low\fR is
accepted and simply saved - no hardware settings are changed and no
errors are generated.  In this case, a call to
\fIe1432_get_input_low\fR will return the most recent value given to
\fIe1432_set_input_low\fR.

.SH "RESET VALUE"
After a reset, \fIlow\fR is set to \fBE1432_INPUT_LOW_FLOATING\fR.
.SH "RETURN VALUE"
Return 0 if successful, a (negative) error number otherwise.
.SH "SEE ALSO"
.na
e1432_set_input_high
.ad
