User`s guide

Reading Device Data
The DEVICE real-valued function returns information about the encoder error status,
position, and velocity. The scale factor, offset, and limits defined by the SETDEVICE
instruction affect the velocity and position values returned.
The syntax for this function is
DEVICE(0, unit, error, select)
The value returned depends upon the value of the select parameter, as described in the
following table.
select Description
0 Read Hardware Status
The error status of the encoder unit is returned as a 24-bit value. The
valid error bits for this device are listed below. The corresponding error
listed is the one V+ would report if the error occurred while tracking a
belt encoder.
Bit # Bit Mask Corresponding Error Message and Code
19 ^H040000 *Lost encoder sync* (-1012)
20 ^H080000 *Encoder quadrature error* (-1013)
21 ^H100000 *No zero index* (-1011)
Only bit #20, for encoder quadrature error, is detected by the error
parameter of the DEVICE function to generate an error.
1 Read Position
The current position of the encoder (in millimeters) is returned, subject
to the scale factor, offset, and limits defined by the SETDEVICE
instruction. The value returned is computed by:
position = scale*(encoder-offset)
position = MAX(position, lower_limit)
position = MIN(position, upper_limit)
2 Read Velocity
The current value of the encoder velocity (in millimeters per second) is
returned, subject to the scale factor defined by the SETDEVICE
instruction. The value returned is computed by:
velocity = scale*encoder_velocity
Select Parameter Values
Reading Device Data
V+Language User's Guide, v17.0
Page 354