RoboteQ AX2850 user manual Read Speed, Or !Q n

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.

156 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007