DIGITAL 
CLOCK 
OPERATION 
FEN, CONTACT 
VOLT METER 
CHART RECORDERS 
n | 
alte PRINTED 
mo. 2 LOGGING TAPE 
EE CONTROL 
S n 3 39 RECORDER 
Oe | EE Se REE 
ow | BRIDGES 
Nr ! 
= | 
26 
ra CARE 
Es oor OUTPUT 
CONTROL 
PRESSURE 
TRANS- 
DUCER 
DEPTH 
BRIDGE 
Figure 8. Digital data recording system 
2. Temperature bridges -- 29 parallel bridges with one common 
power supply; 26 of these are for the temperature sensors and 
the remaining 3 provide special calibrate signals (to be des- 
cribed later). 
3. Pressure transducer and depth bridge -- Described earlier. 
4. Input scanner (Model 760-60) -- Samples 30 two-wire inputs; 
crossbar type with maximum switching speed of approximately 
50 channels per Second. 
5. Amplifier (Model A-15X1) -- Single-ended input de amplifier, 
with fixed gains of 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, 
plus adjustable gain. 
6. Analog-to-digital converter (Digital Voltmeter Model 7409) -- 
This is the heart of the system and has three voltage ranges: 
0-10, 0-100, 0-1000. When on the 0-10 volt range, it meas- 
ures 0.001 volt to 9.999 volts. Maximum conversion rate is 
1000 readings per second. Output to next stage is binary; the 
visual display is decimal. 
15 
