RoboteQ AX2850 - Manual (Page 157)

AX2550 Motor Controller User’s Manual 157
RS232 Encoder Command Set
Read Distance
Description:
This query will cause the controller to return the distance between the current position and
the value in the destination register. The values are signed Hexadecimal numbers ranging
from -127 to +127. The -127 value represents the relative distance according to the formu-
las described in “Using the Encoder to Track Position” on page 81.
Syntax: ?d or ?D
Reply: nn
mm
Where: nn = distance 1 value
mm = distance 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.
Read Speed/Distance
Description:
This query is will cause the controller to return either the speed or the distance computed
by the Encoder module, depending on the operating mode that is selected. This command
is similar to either of the two previous ones, except that it is read from a different location
inside the controller and is a filtered value that smoothened abrupt changes.
Syntax: ?k or K
Reply: nn
mm
Where: nn = speed 1 or distance 1 value
mm = speed 2 or distance 2 value
Read Encoder Limit Switch Status
Description:
This query will cause the controller to return the status of the four optional Encoder limit
switches. The returned value is a two-digit (8-bit) Hexadecimal number of which the each
of the 4 least significant bit represents one of the hardware switches.
Note that for this function to work, limit switches must be connected to the encoder mod-
ule using the special wiring diagram show in “Wiring Optional Limit Switches” on page 78.
If no limit switches are present, this query will return the logic levels of each of the
encoder’s quadrature outputs, which in most cases is not relevant information.
Syntax: ?w or ?W