Z-World Fox LP3500, User Manual

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54 Fox (LP3500)
Reads the voltage of an analog input channel by serial-clocking an 8-bit command to the ADS7870
device by its Direct Mode method. The conversion begins as soon as the last data bit is transferred.
An exception error will occur if Direct Mode bit D7 is not set.
PARAMETER
cmd
contains a gain code and a channel code as follows.
D7—1; D6–D4—Gain Code; D3–D0—Channel Code
Use the following calculation and the tables below to determine
cmd
:
cmd = 0x80 | (gain_code*16) + channel_code
len
, the output bit length, is always 12 bits.
unsigned int anaInDriver(unsigned int cmd,
unsigned int len);
Gain Code Multiplier
Voltage
Range
0 1 0–20 V
1 2 0–10 V
2 4 0–5 V
3 5 0–4 V
4 8 0–2.5 V
5 10 0–2 V
6 16 0–1.25 V
7 20 0–1 V
Channel Code
Differential
Input Lines
Channel Code
Single-Ended
Input Lines
*
* Negative input is ground.
4–20 mA
Lines
0 +AIN0 -AIN1 8 AIN0 AIN0
1 +AIN2 -AIN3 9 AIN1 AIN1
2 +AIN4 -AIN5 10 AIN2 AIN2
3 +AIN6 -AIN7 11 AIN3 AIN3
4 Reserved 12 AIN4 Reserved
5 Reserved 13 AIN5 Reserved
6 Reserved 14 AIN6 Reserved
7 Reserved 15 AIN7 Reserved