RoboteQ AX2850 - Manual (Page 141)

AX2550 Motor Controller User’s Manual 141
Controller Commands and Queries
values represent the actual speed measured by the tachometer. When used in position
mode, the values represent the actual motor position measured by a potentiometer. In all
other modes, the values represent the measured voltage (0 to 5V) applied to the analog
inputs. The values are signed Hexadecimal numbers ranging from -127 to +127. The -127
value represents 0V at the input, the 0 value represents 2.5V, and the +127 value repre-
sents +5V.
Analog 1 and 2
Syntax:
?p or ?P
Analog 3 and 4
Syntax:
?r or ?R
Reply: nn
mm
Where: nn = analog input 1 (or 3) value, speed or position
mm = analog input 2 (or 4) value, speed or position
Notes:
The command returns a signed hexadecimal number where 0 to +127 is represented by 00
to 7F, and -1 to -127 is represented by FF to 80 respectively.
On controllers prior to RevB, querying Analog inputs 3 and 4 will return a meaningless
number.
Query Heatsink Temperatures
Description:
This query will cause the controller to return values based on the temperature measured
by internal thermistors located at each heatsink side of the controller. Because NTC ther-
mistors are non-linear devices, the conversion or the read value into a temperature value
requires interpolation and a look up table. Figure 39 on page 69 shows this correlation.
Sample conversion software code is available from Roboteq upon request. The values are
unsigned Hexadecimal numbers ranging from 0 to 255. The lowest read value represents
the highest temperature.
Syntax: ?m or ?M
Reply: nn
mm
Where: nn = thermistor 1 read value
mm = thermistor 2 read value
Notes:
The hexadecimal format is intended to be deciphered by a microcontroller. When exercis-
ing the controller manually, you may use the Decimal to Hexadecimal conversion table on
page 166.
Query Battery Voltages
Description:
This query will cause the controller to return values based on two internally measured volt-
ages: the first is the Main Battery voltage present at the thick red and black wires. The sec-
ond is the internal 12V supply needed for the controller’s microcomputer and MOSFET