Campbell Scientific CR10 CR10 Measurement and Control - Page 125

SECTION 9. INPUT/OUTPUT INSTRUCTIONS TABLE 9-1. Input Voltage Ranges and Codes Slow 2.72ms 2FR5aan0soept sCode6R0ejHeczt 50 Hz Reject FullScaleRanqe Resolution* Integ. Integ. 1 2 11 21 31 12 22 32 t2.5 mV t7.5 mV 0.33 1. pV pv 3 4 13 23 14 24 33 x2S mV 34 r250 mV 3.33 UV 33.3 pV 5 15 25 35 t2500 mV 333. pV . Differential measurement: resolution tor single-ended measurement is twice value shown. NOTE: When a voltage input exceeds the range programmed, the value which is stored is set to the maximum negative number and displayed as -99999 in high resolution or -6999 in low resolution. *** 1 SINGLE-ENDED VOLTS *** FUNCTION This lnstruction is used to measure voltage at a single-ended input with respect to ground. Output is in millivolts. PARAM. DATA NUMBER TYPE DESCRIPTION 01: 2 Repetitions 02: 2 Range code (Table 9-1) 03: 2 Single-ended channel number for first measurement o4: 4 input location for first measurement 05: FP Multiplier 06: FP Offset Input locations altered: 1 per measurement *** 2 DIFFERENTIAL VOLTS *** FUNCTION This Instruction reads the voltage ditference between the high and low inputs of a differential channel. Table 9-1 contains allvalid voltage ranges and their codes. Both the high and low inputs must be within t2.5 V of the CRl0's ground (see Common Mode Range in Section 14.3.2). Pyranometer and thermopile sensors require a jumper between LO and GROUND to keep them in Common Mode Range. Output is in millivolts. PARAM. DATA NUMBER TYPE DESCRIPTION 01: 2 Repetitions 02: 2 Range code fl'able 9-1) 03: 2 Differential channel number for first measurement 04: 4 lnput location for first measurement 05: FP Multiplier 06: FP Offset Input locations altered: 1 per measurement *** 3 PULSE COUNT *** There are three pulse input types which may be measured with the Pulse Count Instruction. HIGH FREQUENCY PULSE In this configuration, the minimum detectable pulse width is 2 microseconds, i.e. the maximum frequency is 250 kHz with a 5O%" duty cycle. The 8 bit counter has a maximum input frequency of 2000 Hz and the 16 bit option a maxirnum of 250 kHz. The count is incremented when input voltage changes from below 1.5 volts to above 3.5 volts. The maximum input voltage is +20 volts. A problem, however, arises when the pulse is actually a low frequency signal (below about 10 Hz) and the positive voltage excursion exceeds 5.6 VDC" 9-1