RoboteQ AX2850 - Manual (Page 156)

156 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
While resetting is a single step command, setting the counters to a non-zero value requires
two steps: 1- load a 4 byte buffer (32-bit) with the desired value. 2- Transfer the buffer’s
content to the counter(s). Loading the buffer can be done using the commands described
in “Read / Modify Encoder Module Registers and Parameters” on page 158. The buffer will
also be altered after a Counter Read command, in which case it will contain the last read
counter value.
Syntax: !q or !Qn
Where n= 0: Reset Encoder 1 counter
1: Reset Encoder 2 counter
2: Reset both Encoder counters
4: Set Encoder 1 counter with value in buffer
5: Set Encoder 2 counter with value in buffer
6: Set both Encoder both counters with value in buffer
7: Set Encoder 1 destination register with value in buffer
8: Set Encoder 2 destination register with value in buffer
Reply: + if command was properly received and executed
- if an error occurred
Examples:
!Q2
Reset both counters
!Q5 Load value contained in buffer into counter 2
?Q0, followed by
!Q1
Read counter 1 and copy its value into counter 2
Read Speed
Description:
This query will cause the controller to return the speed computed by the Encoder module.
The values are signed Hexadecimal numbers ranging from -127 to +127. The -127 value rep-
resents the maximum RPM in the reverse direction. +127 represents the maximum RPM
in the forward direction. The relation of this relative number and the actual, absolute RPM
value depends on the encoder’s resolution and a user programmable Time Base. See
“Using the Encoder to Measure Speed” on page 80 for a detailed discussion.
Syntax: ?z or ?Z
Reply: nn
mm
Where: nn = speed 1 value
mm = speed 2 value
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. The hexadecimal format is
intended to be deciphered by a microcontroller. When exercising the controller manually,
you may use the Decimal to Hexadecimal conversion table on page 167.