Analog Inputs

The Guidance Controller supports 2 general purpose analog inputs as shown in the table below. These values may be used internally by the motion system or may be accessed by a GPL procedure.

Signal Number	I/O	Label	Description
10001	I	AIN_1	Analog input 1
10002	I	AIN_2	Analog input 2

These analog inputs use 12-bit bipolar analog-to-digital converters (ADCs) to convert +/- 10-volt signals, so the raw converted values are:

10 volts = 2047
-10 volts = -2048

The scale factors, offsets, and limits for the analog inputs are determined by the parameter database values shown in the table below:

Parameter Database ID	Parameter Name	Default Value	Description
524	Gen AIO In scale factor	1	An array of scale factors, one per channel, that are applied to the analog input values when converting them from raw ADC units.
525	Gen AIO In offset	0	An array of offsets, one per channel, that are applied to the scaled analog input values when converting them from raw ADC units.
526	Gen AIO In min scaled value	-32768	An array of minimum values, one per channel, that are compared to the scaled and offset analog input values. If a converted value is less than this limit it is set to the limit.
527	Gen AIO In max scaled value	32767	An array of maximum values, one per channel, that are compared to the scaled and offset analog input values. If a converted value is greater than this limit it is set to the limit.

The converted input value is computed according to the equation below:

converted value = (raw ADC reading * scale factor) + offset

After the conversion, the converted value is clipped if necessary to remain within the minimum and maximum values.

Whenever a GPL instruction retrieves an ADC value, it obtains the last value converted by the hardware. For the Guidance family of controllers, the ADC's are operated continuously by the hardware so each value is only a few microseconds old when read. Please see the controller hardware section for specific information on the ADC conversion rate.