Digi RCM4000 Unsigned int anaInDriverunsigned int cmd, unsigned int len, Gain Code Multiplier

unsigned int anaInDriver(unsigned int cmd, unsigned int len);

Reads the voltage of an analog input channel by serial-clocking an 8-bit command to the A/D converter by its Direct Mode method. This function assumes that Mode1 (most significant byte first) and the A/D converter oscillator have been enabled. See anaInConfig() for the setup.

The conversion begins immediately after the last data bit has been transferred. An exception error will occur if Direct Mode bit D7 is not set.

PARAMETERS

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

		Gain Code		Multiplier
		0		×1
		1		×2
		2		×4
		3		×5
		4		×8
		5		×10
		6		×16
		7		×20
Channel Code	Differential Input		Channel Code		Single-Ended		4–20 mA
	Lines				Input Lines*		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	-AIN0 +AIN1			12		AIN4	AIN4
5	-AIN2 +AIN3			13		AIN5	AIN5
6	-AIN4 +AIN5			14		AIN6	AIN6
7‡	-AIN6 +AIN7			15		AIN7	AIN7*

* Negative input is ground.

†Not accessible on Prototyping Board

‡ Not accessible on Prototyping Board

len, the output bit length, is always 12 for 11-bit conversions

User’s Manual 49