Signal Quality¶
Description¶
The signal quality is specified in percent steps as a value between 0 and 100%. If the signal quality cannot be provided, a substitute value of 0xFF (255) is output. The threshold value for the monitoring function can be set and is used to define two states of the signal quality. The signal quality is considered to be good at or above the threshold value; the signal quality is considered to be bad below the threshold value. A state change from good to bad signal quality triggers the Low Signal Quality Level IO-Link event.
The output of the current signal quality can provide support both when setting up as well as during predictive maintenance. When setting up, the location, the orientation and the environmental conditions can be adapted to achieve a satisfactory signal quality level. If the signal quality is checked regularly, a deterioration of the performance can be preventatively combated.
In addition, the monitoring of the signal quality offers an immediate response in the event of a critical failure. This reaction is triggered if the signal quality drops below the adjustable threshold value and gives the all clear if a satisfactory signal quality level is once again achieved.
The signal status is indicated by LED (see section LED meaning and configuration).
The function can be deactivated by setting the threshold value to zero.
Mathematics/Algorithm¶
The signal quality value is based on the Target Strength signal. If the Target Strength is below a defined lower threshold (3dB), the signal quality is set to 0%. If the Target Strength is above an upper threshold (20dB), the signal quality is set to 100%. For values in between, the function linearly maps the Target Strength to a percentage between 0% and 100%.
Process Data¶
| Object ID | Name | Description | Direction |
|---|---|---|---|
| 0x0021 (33) | Signal Quality Bad | Output of the current signal quality evaluation; TRUE means a signal quality below the threshold value, FALSE means a signal quality equal to or above the threshold value. |
Input |
Also see section Process Data Profiles.
ISDU¶
| Name | Index | Subindex | Access | Length | Data Type | Data Storage |
Default |
|---|---|---|---|---|---|---|---|
| Low Signal Quality Threshold | 0x00CE (206) | 0 | R/W | 1 byte | UINT8 | Yes | 0 |
| Signal Quality | 0x00CF (207) | 0 | R | 2 bytes | n/a | ||
| Current Signal Quality | 1 | R | 1 byte | UINT8 | n/a | – | |
| Signal Quality Bad | 2 | R | 1 bit | BOOL | n/a | – |
Low Signal Quality Threshold¶
The threshold value for low signal quality can be set in order to monitor the current signal quality. It is displayed as a value between 0 and 100 in percent. If the current signal quality value drops below the signal quality threshold value, the Low Signal Quality Level warning is output.
The function can be deactivated by setting the threshold value to zero.
Current Signal Quality¶
The current signal quality is displayed as a value between 0 and 100 in percent. If no valid signal quality is available, the value is set to 255.
Signal Quality Bad¶
The status of the signal quality is displayed as a Boolean value. If the value is TRUE, the signal quality is below the threshold value; if the value is FALSE, the signal quality is equal to or greater than the threshold value.
System Commands¶
| Command Value |
Device Action |
|---|---|
| 0x81 (129) | Application Reset – Sets the threshold value with ISDU index 0xCE Low Signal Quality Threshold to default 0. The feature is thereby deactivated and the evaluation of index 0xCF subindex 2 always results in FALSE. |
| 0x82 (130) | Restore Factory Settings – Sets the threshold value with ISDU index 0xCE Low Signal Quality Threshold to default 0. The feature is thereby deactivated and the evaluation of index 0xCF subin dex 2 always results in FALSE. |
For an overview of all System Commands, see section System commands.
Events¶
| Event Code | Event Type | Event – Description – Remedy | Device Status |
|---|---|---|---|
| 0x8CFF (36095) |
Warning | Low signal quality level | 2 – Out-of Specification |
Variant Dependence¶
The functionality is available only in Distance/ Object detection variant.