CompuScope SDK Manua.. - Egmont Instruments

gage_capture_mode
Syntax
C:
int16 GAGEAPI gage_capture_mode (int16 mode, int16 rate, int16 multiplier);
Visual BASIC:
function gage_capture_mode (ByVal mode As Integer, ByVal rate1 As Integer,
ByVal multiplier As Integer): As Integer
Remarks
The gage_capture_mode routine is used to set the mode and sampluing rate that will be used for the next
CompuScope acquisition.
mode is the desired mode of capture, either single (GAGE_SINGLE_CHAN) or dual
(GAGE_DUAL_CHAN). Some CompuScope models may only support one of the two modes.
GAGE_QUAD_CHAN can also be used for digital input CompuScopes like the CS3200.
The rate and multiplier values together form the requested sample rate. For example, to request a 10
MS/s sample rate, the rate would be set to 10 (or preferably GAGE_RATE_10) and multiplier to
GAGE_MHZ.
The rate can be any valid value. Check your CompuScope Hardware Manual for valid rates for your
CompuScope model. The valid multiplier values are as follows and are defined in GAGE_DRV.H file.
#define GAGE_HZ 1
#define GAGE_KHZ 2
#define GAGE_MHZ 3
#define GAGE_GHZ 4
#define GAGE_EXT_CLK 5
The multiplier value GAGE_EXT_CLK is used to set the CompuScope external clock mode, if your
CompuScope is equipped with the external clock feature. When using external clock, the rate should
normally be set to 0. The actual external clock rate should be set before calling gage_capture_mode
routine with a call to gage_set_ext_clock_variables routine. This is an important step, since the drivers
must know what the actual external clock frequency is in order to appropriately set internal low level
timing values on the CompuScope hardware.
On some CompuScope boards (for example CS8500) the values 1, 2, 4, 8 for rate can also be used with
external clock (multiplier value = GAGE_EXT_CLK). These non-zero settings will decimate thesupplied
external clock signal by the rate factor, if supported.
The gage_capture_mode routine is generally only called once before a series of acquisitions in order to set
the input mode and sampling rate. The call to gage_capture_mode is generally made in conjunction with
calls to gage_set_ext_clock_variables (if using external clock), gage_multiple_record (if using Multiple
Record mode), gage_input_control (to control input settings) and gage_trigger_control (to set trigger
parameters) in order to set up the CompuScope hardware for the next acquisition. These routines need
only be called once unless you need to change any parameters for a subsequent acquisition.
CompuScope API Reference Manual 24