Geometrics Memory-Mag G-856AX, Operation Manual

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Geometrics, Inc
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G-856AX Operation Manual
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a logical "0" (space, on or true state) is indicated when the voltage is more positive than
+3V. RS-232 devices, including the G-856AX use 0 and +5 volts for these two logic
levels ("TTL levels") instead of ±12V. Most devices designed to work with ±12V levels
will operate correctly with TTL levels but there are exceptions. Many large mainframe
computers and some minicomputers require data over long cables. If your external
equipment requires full ±12V RS-232 levels, you will need to construct or purchase a
TTL-to-bipolar interface driver.
Front panel connector pin assignment
Pin Function Remarks
A Sensor
B Sensor
C Sensor shield
D Ground Power and control ground
E No connection
F Data accepted Input from external device
G Clear to send
H Battery positive Connected to Internal Battery
J Data 0 Serial BCD is no longer used
K Data 1 Character
L Data 2 Serial
M Data 3 BCD out
N Data valid
P End of data
R Instrument power External Power in. Otherwise jumper to H
S Synchronization External read/store command
T Transmit data
U Receive data
Part of RS-232
Output format
When attempting to transfer data from the G-856AX to a generic device, make sure that
the baud rates of the magnetometer and device match and that G-856AX Txd line is
connected to device’s Rxd line. The G-856AX serial data format (RS-232) and BCD
outputs are as follows:
a. Each transmitted character is in ASCII code and consists of:

1 start bit (always logic "1")

7 data bits (ASCII encoded)

1 parity bit (always logic "0")

2 stop bits (always logic "0")
b. Each line of data transmitted by the G-856AX consists of 29 ASCII characters.
Listed in order, the data fields and their count is as follows:

Space or asterisk (*) - 1

Line number - 3