Campbell Scientific CR10 CR10 Measurement and Control - Page 137

PARAM. NUM. TDAYTAPE 01: a2: 4 4 DESCRIPTION MASK (0-255) INPUT LOCATION TO STORE RESULT Input locations altered: 1 *** 26 TIMER *** FUNCTION This instruction will reset a timer or store the elapsed time registered by the timer in seconds in an lnput Storage location. Instruction 26 can be used with Program Control lnstructions to measure the elapsed time between specific input conditions. There is only one timer and it is common to alltables (e.9., if the timer is reset in Table 1 and later in Table 2, a subsequent instruction in Table 1 to read the timer will store the elapsed time since the timer was reset in Table 2). Elapsed time is tracked in 0.125 second increments. The maximum intervalthat can be timed is 8191.875 seconds. The timer is also reset in response to certain keyboard entries: 1. When tables are changed and compiled with the *0 Mode, the timer is reset automatically. 2. Entering "*6" after changing the program compiles the programs, but does NOT reset the timer. PARAM. NUM. TDAYTAPE 01: 4 DESCRIPTION Input location no. of elapsed time in seconds (or enter 0 to reset) Input locations altered: 1 (0 if timer is being reset) *** 27 PERIOD MEASUREMENT *'* FUNCTION Instruction 27 measures the period (microseconds) of a signal on a single ended input channel. As an option, the frequency of the signal in kHz may be output instead of the period. The specified number of cycles are timed with a resolution of +60 nanoseconds, SECTION 9. INPUT/OUTPUT INSTRUCTIONS making the resolution on the period 60 nanoseconds divided by the number of cycles measured. Resolution is reduced by noise and signals with a slow transition through the zero voltage threshold. The "Time out" parameter specifies the maximum length of time the instruction will wait on each repetition for the specified number of cycles. lf the cycles have not been counted within this time, -99999 will be loaded into the input location. Input Frequency Gain Codes Range Peak to Peak Volts Maximum Code Required @ Max. Freo.* Frequencv 1 2 2 mV 3 mV SkHz 20kHz 3 4 12 2 mV V 50 kHz 200 kHz 0x Output period in microseconds 1x Output frequency in kHz where x is range code * AC voltage; must be centered around CR10 ground. NPAURMAM. . TDAYTAPE DESCRIPTION 01: 2 Repetitions 02: 2 Gain/output option 03: 2 Single-ended input channel o4:, 4 # Cycles to measure 05: 4 Time out (0.01 sec, at least the maximum duration of the number of cycles specified + 'l 1/2 cycles.) 06: 4 Destination input location 07: FP Multiplier 08: FP Offset Input locations altered: 1* Repetitions *** 28 VIBRATING WIRE *** MEASUREMENT FUNCTION Excites a vibrating wire sensor with a swept frequency (from low frequency to high), then measures the response period and calculates 1ff2, where T is the period in ms. Excitation is normally provided for before each repetition. As an option, a single excitation can be made prior to all repetitions of the measurement. An AVW1 or AVW4 Vibrating Wire Interface is usually required for these sensors. 9-13