Measurement Computing StrainBook/616 User Manual
Page 100
8-4 Digital I/O, TTL Trigger, and External Clock
977794
StrainBook/616
StrainBooks have a 32-bit internal counter that calculates and reports the external clock’s period. The
counter can be read with each scan of the analog data. This is often beneficial in later analysis, when there
is a need to correlate physical phenomena with speed.
The counter channel actually consists of two independent channels (CtrLo and CtrHi). These can be turned
“On” in the Channel Configuration Spreadsheet. When enabled, the low (CtrLo), then high (CtrHi) words
of the counter will be configured in each scan. Note that the spreadsheet’s Units column can be used to
view a predefined period in units of seconds, ms, or µsec.
WaveView can be configured to read only the low word of the counter data (CtrLo:“On,” CtrHi: “Off”).
This decreases the minimum scan period by 1 usec. This LoCtr only option can be used only when the
external clock frequency is greater than 305 Hz (20,000,000 MHz / 65536]. Note that WaveView does not
enforce this.