Lika MTA1, User Manual

Page: 32 / 48

SMA1
7.3 Single Cycle Data
SCD (32 bits) consists of the following values: 24-bit position value (
Position
), 1
error bit (
Error
, nE), 1 warning bit (
Warning
, nW) and CRC checking (
CRC
, 6
bits).
SCD structure:
bits 31…8 7 6 5…0
function Position Error Warning CRC
Position
(24 bits)
Process data to be transmitted from the Slave to the Master.
The transmission starts with the MSB (most significant bit) and ends with the
LSB (least significant bit).
bit 31 … 28 27 … 8
value
0000 MSB … LSB
To convert the position value into mm, multiply the received data value by the
resolution (see 4Dhex
Absolute resolution register).
EXAMPLE 1
SMA1-SB2-5-...,
Absolute resolution
= 32 hex, 0.05 mm
detected pulses = 123
position = 123 * 0.05 = 6.15 mm
EXAMPLE 2
SMA1-SB2-5-...,
Absolute resolution
= 64 hex, 0.1 mm
detected pulses = 1569
position = 1569 * 0.1 = 156.9 mm
Error
(1 bit)
It is intended to communicate the normal or fault status of the Slave.
nE = “1”: correct status (no active error)
= “0”: error status: the scale is not sensed properly.
Check the gap between the sensor and the scale, check both
planarity and parallelism. See the “3 - Mounting instructions”
section on page 11.
Warning
(1 bit)
Not used (nW = “1”)
MAN SMA1 E 2.9.odt 7 - BiSS C-mode interface 32 of 48