Campbell Scientific CR7 Measurement and Control System - Manual (Page 91)

9-1
SECTION 9. INPUT/OUTPUT INSTRUCTIONS
TABLE 9-1. Input Voltage Ranges and Codes
Range Code Full Scale Range Resolution*
Slow Fast
16.67ms 250µs
Integ. Integ.
1 11 ±1500 microvolts 50 nanovolts
2 12 ±5000 microvolts 166 nanovolts
3 13 ±15 millivolts 500 nanovolts
4 14 ±50 millivolts 1.66 microvolts
5 15 ±150 millivolts 5 microvolts
6 16 ±500 millivolts 16.6 microvolts
7 17 ±1500 millivolts 50 microvolts
8 18 ±5000 millivolts 166 microvolts
*Differential measurement, resolution for single-ended measurement is twice value shown.
When measuring voltages with the 723
Analog Input Card, the ±1500 µV and
±5000 µV ranges read out in microvolts, the
rest of the ranges have the decimal point
placed to display millivolts. The 726 50V
Analog Input Card divides the input voltages
by 10 before making the measurements,
thus, to shift the decimal point so as to
display millivolts a factor of ten must be
used in the multiplier. Repetitions cannot
be used to advance from one 726 card to
the next.
When a voltage input exceeds the range
programmed, the value which is stored is
set to the maximum negative number
displayed as -99999 in high resolution or -
6999 in low resolution.
*** 1 SINGLE ENDED VOLTS ***
FUNCTION
This instruction is used to measure voltage at a
single ended input with respect to ground.
PAR. DATA
NO. TYPE DESCRIPTION
01: 2 Repetitions
02: 2 Range code (Table 9-1)
03: 2 Card number for first
measurement
04: 2 Single-ended channel
number for first
measurement
05: 4 Input location number for first
measurement
06: FP Multiplier
07: FP Offset
Input locations altered: 1 per repetition
*** 2 DIFFERENTIAL VOLTS ***
FUNCTION
This Instruction reads the voltage difference
between the HI and LO inputs of a differential
channel in the selected range from the selected
card and channel(s) and places it in an input
location(s). Table 9-1 lists the range codes.
Both the high and low inputs must be within ±5V
of the datalogger's ground (Common Mode
Range Section 13.2). Pyranometers and
thermopile sensors require a jumper between
LO and Ground to keep them in Common Mode
Range.