Manning YB8, Руководство по эксплуатации и инструкция

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PROGRAMMING SECTION MODEL YB8
April 1999/Manning Environmental Inc.
3DJH%
The analog display routine allows the operator to display the analog signal received from an external meter
(level, flow pH, etc.). This routine can be used while the sampler is being installed, connected to a flow meter,
or to check the calibration of the sampler’s analog to digital converter.
The program is started by entering <*08> at the “SAMPLER READY” prompt. The analog value will be
displayed in three formats: 1) As a digital value (0 to 255); 2) As a DC voltage (1 to 5 VDC); and 3) in
milliamps (4.0 to 20.0 mA). The program will continue to loop until reset by the operator pressing the
<RESET> key twice. The analog input signal can be varied while the program is running and the display will
change accordingly.
The sampler’s analog routine can be calibrated by inputting a known milliamp signal or attaching a variable
voltage source across the analog input terminals.
ANALOG VALUES TABLE
TABLE A1
mA DC VOLTS DIGITAL
VALUE
4.0 1.00 000
5.0 1.25 015
6.0 1.50 031
7.0 1.75 047
8.0 2.00 063
9.0 2.25 079
10 2.50 095
11 2.75 111
12 3.00 127
13 3.25 143
14 3.50 159
15 3.75 175
16 4.00 191
17 4.25 207
18 4.50 223
19 4.75 239
20 5.00 255
Table A1 is a conversion table for the analog values. For example, if a voltage of 3.00 volts is placed across
the analog input terminals the sampler should display 12 mA, 3.00 VDS and a digital value of 127. The analog
input circuit is designed with a precision 250 ohm resistor across the input terminals. When an mA analog
signal is input the current flows through the 250 ohm resistor generating a voltage drop proportional to the
current flow. At 12 mA the voltage drop is .012x250 = 3.00 volts. The three volts is converted into a digital
value 127. When a three volt signal is placed across the analog input terminals it generates a current flow
according to ohms law of I = 3/250 = .012 mA.
*08 Analog Display Routine