Omega OME-A822PG manual 6 A/D Gain Control Register, GAIN3 GAIN2 GAIN1 GAIN0

2.4.6A/D Gain Control Register

(WRITE)	Base+9 : A/D Gain Control Register Format
Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
X	X	X	X	GAIN3	GAIN2	GAIN1	GAIN0

The only difference between the OME-A-822PGL and OME-A-822PGH is the GAIN control function. The OME-A-822PGL provides gains of 1/2/4/8 and the OME-A-822PGH provides gains of 1/10/100/1000. The gain control register control the gain of the A/D input signal. Bipolar/Unipolar will affect the gain factor.

It is important to select the correct gain-control-code according to Bipolar/Unipolar input.

NOTE : If the gain control code is changed, the hardware needs an extra delay for

the gain settling time. The gain settling time is different for the different gain control codes.

The software driver does not take care the gain settling time, so the user needs to add

the delay . If the application program will run on different machines, the user needs to implement a machine independent timer. The software driver, A-822_delay(),is designed for this purpose. If this subroutine is used, then counter2 as described in sec 2.6 is reserved by the software driver to implement the machine independent timer.

OME-A-822PGL GAIN CONTROL CODE TABLE

BI/UNI	Settling Time	GAIN	Input Range	GAIN3	GAIN2	GAIN1	GAIN0
BI	23 us	1	+/- 5V	0	0	0	0
BI	23 us	2	+/- 2.5V	0	0	0	1
BI	25 us	4	+/- 1.25V	0	0	1	0
BI	28 us	8	+/- 0.0625V	0	0	1	1
UNI	23 us	1	0V to 10V	0	1	0	0
UNI	23 us	2	0V to 5V	0	1	0	1
UNI	25 us	4	0V to 2.5V	0	1	1	0
UNI	28 us	8	0V to 1.25V	0	1	1	1
BI	23 us	0.5	+/- 10V	1	0	0	0

BI=Bipolar, UNI=Unipolar, X=don‘t care, N/A=not available

OME-A-822PGL/PGH Hardware Manual ---- 20