RoboteQ AX3500 Connecting User Devices to Analog Inputs, Internal Voltage Monitoring Sensors

Connecting User Devices to Analog Inputs

Measured volts = ((controller reading + 128) * 0.255) -5

Note: The A/D converter’s reading is returned by the ?p command and is a signed 8-bit hexadecimal value. You must add 128 to bring its range from -127/+127 to 0/255.

Connecting User Devices to Analog Inputs

The two analog inputs can be used for any other purpose. The equivalent circuit for each input is shown in Figure 37. The converter operates with an 8-bit resolution, reporting a value of 0 at 0V and 255 at +5V. Care should be taken that the input voltage is always posi- tive and does not exceed 5V. The converter’s intrinsic diodes will clip any negative voltage or voltage above 5V, thus providing limited protection. The value of the analog inputs can be read through the controller’s RS232 port.

	+5V 14
Ana 1: 11		47kOhm
Ana 2: 10		A/D
Ana 3: 12
Ana 4:	8	10kOhm
		47kOhm
Ground 5

FIGURE 37. AX3500 Analog Input equivalent circuit

Internal Voltage Monitoring Sensors

The AX3500 incorporates voltage sensors that monitor the Main Battery voltage and the Internal 12V supply. This information is used by the controller to protect it against overvolt- age and undervoltage conditions (see “Overvoltage Protection” on page 38 and “Under- voltage Protection” on page 38). These voltages can also be read from the RS232 serial port using the ?e query.

The returned value are numbers ranging from 0 to 255. To convert these numbers into a Voltage figure, the following formulas must be used:

Measured Main Battery Volts = 55 * Read Value / 256

Measured Internal Volts = 28.5 * Read Value / 256

Internal Heatsink Temperature Sensors

The AX3500 includes temperature sensors near the transistor of each of the two output stages.

AX3500 Motor Controller User’s Manual 67