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7.2 Process data (PD)
The variants of the BML use the IO-Link interface to output
a cyclical measurement value along with status and
switching point information.
Byte
5 4 3 2 1 0
Measured value
Scaling
factor
Status
and
SSCs
Tab. 7-2: Process data
Measurement value
The measurement value represents the position of the
sensor head in μm and consists of a signed 32-bit value.
Scaling factor
The scaling factor is a constant, signed 8-bit number
which indicates the power of ten by which the
measurement value must be multiplied in order to convert
it into the SI unit of meters .
For the BML the scaling factor is –6 (0xFA):
Measurement value × 10
−6
= Position [m]
Status and SSC
Bit Name Function
7 System Error The BML is no longer functional
(memory error, hardware defect).
6 Out of Range /
No
Measurement
Data
The BML is not detecting a
magnetic tape within the
detection range.
5 – not used
4 Measurement
Value Unsafe
The sensor head is within the set
measuring range but the excess
gain is too low. The threshold for
the signal can be set using the
parameter Low Signal Quality
Threshold (see Section 7.5.11).
(Available only for
BML SL1-ALZ1-UEZZ-_U1L-…)
3 SSC 4 Switching information for the
fourth switching point
2 SSC 3 Switching information for the third
switching point
1 SSC 2 Switching information for the
second switching point. In SIO
mode SSC2 is placed on OUT2.
0 SSC 1 Switching information for the first
switching point. In SIO mode SSC
1 is placed on OUT 1.
Tab. 7-3: Status and SSCs
While the sensor head cannot provide current process
data, the process data are designated as invalid using the
PD Invalid Bit . It can happen that during configuration no
measurement can be performed, so that no current
measurement data are able to be output. Output of the
PD
Invalid Bit can be disabled (see Diagnostics suppression
on page 35).
The IO-Link functionality PD Invalid Bit is
handled differently by different IO-Link masters
(see manual for the master used). Output of the
PD Invalid Bit can be suppressed using the
parameter Diagnosis Suppression (see
Diagnostics suppression on page 35).
Measur
ed value
No Measur
ement Data
No Measur
ement Data
Out of range (negative)
Out of range (positive)
Position
Measuring range
Status bits
1)
Bit 4 0 0 0/1
2)
0 0
Bit 6 1 1 0 1 1
1)
see Tab. 7-3
2) If this bit is set, the excess gain is too low. The magnetic tape is
damaged or offset too far.
Fig. 7-1: Ranges and output
If the BML is still on the magnetic tape but outside the
detection/measuring range, the process data variable is
replaced by the following values:
– Out of Range positive:
2'147'483'640 (0x7FFFFFF8)
– Out of Range negative:
–2'147'483'640 (0x80000008)
A measurement error occurs if no magnetic tape is
detected, the functional space is not maintained (see
Tab. 4-2 on page 11) or the sensor head is not
completely on the measuring tape. In this case the process
data variable is replaced by the error value
2'147'483'644
(0x7FFFFFFC)
(No Measurement Data).
7
IO-Link Smart Sensor Profile Ed. 2 (BML SL1-ALZ1-UE/MZZ-_U1L-…) (continued)
BML SL1-ALZ _ -U_ ZZ- _ U1L - _ _ _ _
Absolute magnetic encoder system
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