Stroke monitoring

The stroke monitoring feature contains the following components:

Distance counter
Stroke counter
Deviation monitoring

This feature supports up to 3 independent stroke channels. Each channel can be configured and enabled separately. A stroke channel is determined by the start and end switching point. One switching point can be used in multiple stroke channels.

../../../_images/stroke_monitoring_overview.png — Stroke monitoring - overview

L: nominal length of the BTL
CHx: stroke channels
SSCx: switching points

Distance counter

Description

The distance counter records the distance taken by the first position magnet (forward and backward as well). The value is determined independently of the configuration of the stroke channels and is specified as an absolute value. The counter is updated periodically.

A jitter window is used to determine the smallest recorded movement, therefore the position magnet movement must be greater than the value of this window. The window size can be adapted to the application.

../../../_images/stroke_monitoring_jitter_window.png — Stroke monitoring - jitter window

M: target position (first position magnet)
ω: jitter window

The following distance counters are available:

Distance counter - values
Distance value	Meaning
Actual distance	Value since the last sensor start (or reset)
Since startup	Value since the last boot-up
Since reset	Value since the last reset
Lifetime	Value since the sensor was delivered

All distance counter values are represented in μm.

Note

The Actual distance can be reset by the Reset distance system command, while the Since reset counter is reset by a Maintenance reset.

It is not possible to reset Lifetime distance.

Note

The Lifetime distance counter can be read out via SSI additional data (Movement distance).

Stroke counter

Description

The stroke counter counts the strokes performed for each activated stroke channel depending on the selected mode. The following counters are available for each channel:

Stroke counter - values
Stroke counter	Meaning
Actual value	Value since the last sensor start
Since reset	Value since the last maintenance reset
Lifetime	Value since the sensor was delivered

Note

Only completed strokes are counted. Depending on the CHx stroke mode parameter the meaning of a complete stroke can vary, please refer to the stroke mode description.

Stroke deviation

Description

The stroke deviation feature constantly monitores the position deviation from the switching points assigned to a given channel. If the target position is within the CHx sensing window, the current deviation value is determined.

../../../_images/stroke_monitoring_sensing_window.png — Stroke monitoring - sensing window

SSCx: switching point
M: target position (first position magnet)
W: sensing window
Δ: deviation

Stroke deviation - values
Deviation value	Meaning
Actual deviation	If position is in the sensing window, then the current deviation from the switching point. Otherwise the last minimum deviation.
Since startup	Relative deviation since the last boot-up
Since reset	Relative deviation since the last reset
Lifetime	Value since the sensor was delivered

For a given channel the Actual deviation value is in μm and it is a signed value. The other deviation values are statistical (relative) values expressed in percentage, refering to the channel’s stroke length in μm.

Note

Because the statistical deviation values are referring to the channel’s stroke length for longer stroke lengths these values will be effectively zero. These values mostly usefull for applications requiring short stroke lengths.

ISDU

Stroke monitoring configuration

Stroke monitoring – configuration ISDU
Name	Index	Subindex	Access	Length	Data Type	Data Storage	Default
Stroke monitoring config.	0xA9 (169)	0	R/W	2	RECORD	Yes
CH1 SSC start		1	R/W	1	ENUM (UINT8)	No	0x00 (0)
CH1 SSC end		2	R/W	1	ENUM (UINT8)	No	0x00 (0)
CH1 sensing window		3	R/W	4	UINT32	No	0x00 (0)
CH1 stroke mode		4	R/W	1	ENUM (UINT8)	No	0x00 (0)
CH1 enable		5	R/W	1	BOOL	No	0x00 (0)
CH2 SSC start		6	R/W	1	ENUM (UINT8)	No	0x00 (0)
CH2 SSC end		7	R/W	1	ENUM (UINT8)	No	0x00 (0)
CH2 sensing window		8	R/W	4	UINT32	No	0x00 (0)
CH2 stroke mode		9	R/W	1	ENUM (UINT8)	No	0x00 (0)
CH2 enable		10	R/W	1	BOOL	No	0x00 (0)
CH3 SSC start		11	R/W	1	ENUM (UINT8)	No	0x00 (0)
CH3 SSC end		12	R/W	1	ENUM (UINT8)	No	0x00 (0)
CH3 sensing window		13	R/W	4	UINT32	No	0x00 (0)
CH3 stroke mode		14	R/W	1	ENUM (UINT8)	No	0x00 (0)
CH3 enable		15	R/W	1	BOOL	No	0x00 (0)
Global enable		16	R/W	1	BOOL	No	0x00 (0)
Data storage cycle		17	R/W	2	UINT16	No	0x00 (0)
Jitter window		18	R/W	2	UINT16	No	0x00 (0)

CHx start

Switching signal channel index which marks the stroke channel’s start position. Multiple stroke channels can use the same switching signal channel.

Stroke monitoring - SSC indices
SSC	Value
SSC1.1	0x00 (0)
SSC1.2	0x01 (1)
SSC1.3	0x02 (2)
SSC1.4	0x03 (3)

CHx end

Switching signal channel index which marks the stroke channel’s end position. Multiple stroke channels can use the same switching signal channel.

Stroke monitoring - SSC indices
SSC	Value
SSC1.1	0x00 (0)
SSC1.2	0x01 (1)
SSC1.3	0x02 (2)
SSC1.4	0x03 (3)

CHx sensing window

The sensing window marks a symmetrical interval around a channel’s switching point, where the stroke deviation is determined. The window size must be between 100 μm and 100.000 μm (10 cm), including the limits.

CHx stroke mode

Defines the stroke mode for the given channel. The available stroke modes are the following:

Channel stroke mode – options
Value	Meaning
0x00 (0)	Single way
0x01 (1)	Single way - reverse
0x02 (2)	Double way
0x03 (3)	Double way - reverse

CHx enable

Enables or disables a specific stroke channel.

Global enable

Enables or disables the stroke monitoring feature in general.

Data storage cycle

The counter values are periodically stored into non-volatile memory of the sensor. This cycle can be configured here. The cycle time must be between 60 and 3600 seconds, including the limits. The parameter is in seconds.

Jitter window

A jitter window is used to determine the smallest recorded movement. Shorter movements than the jitter window size are not recorded. The parameter is in μm and must be between 10 μm adnd 50.000 μm, including the limits.

Note

Setting the Jitter window to the minimum can have the risk that increased noise in the position can be recorded as movement.

Distance counter

Stroke monitoring – distance counter ISDU
Name	Index	Subindex	Access	Length	Data Type	Data Storage	Default
Distance counter	0xAA (170)	0	R	32	RECORD	n/a
Actual distance		1	R	8	UINT64	n/a	-
Since startup		2	R	8	UINT64	n/a	-
Since reset		3	R	8	UINT64	n/a	-
Lifetime		4	R	8	UINT64	n/a	-

Actual distance

Distance travelled by the first position magnet since the sensor is powered or since the last Distance reset command. The value is in μm.

Since startup

Distance travelled by the first position magnet since the sensor is powered. The value is in μm.

Since reset

Distance travelled by the first position magnet since the last Maintenance reset is executed. The value is in μm.

Lifetime

Total distance travelled by the first position magnet since delivery. This value cannot be reset. The value is in μm.

Stroke counter

Stroke monitoring – stroke counter ISDU
Name	Index	Subindex	Access	Length	Data Type	Data Storage	Default
Stroke counter	0xAB (171)	0	R	72	RECORD	n/a
CH1 actual		1	R	8	UINT64	n/a	-
CH1 since reset		2	R	8	UINT64	n/a	-
CH1 lifetime		3	R	8	UINT64	n/a	-
CH2 actual		4	R	8	UINT64	n/a	-
CH2 since reset		5	R	8	UINT64	n/a	-
CH2 lifetime		6	R	8	UINT64	n/a	-
CH3 actual		7	R	8	UINT64	n/a	-
CH3 since reset		8	R	8	UINT64	n/a	-
CH3 lifetime		9	R	8	UINT64	n/a	-

CHx actual

Shows the current stroke count since the sensor startup.

CHx since reset

Shows the stroke count since the last Maintenance reset.

CHx lifetime

Shows the total number of strokes on a given channel since the sensor was shipped. This value cannot be reset.

Stroke deviation

Stroke monitoring – stroke deviation ISDU
Name	Index	Subindex	Access	Length	Data Type	Data Storage	Default
Stroke counter	0xAB (171)	0	R	48	RECORD	n/a
CH1 actual		1	R	4	INT32	n/a	-
CH1 startup relative		2	R	4	INT32	n/a	-
CH1 reset relative		3	R	4	INT32	n/a	-
CH1 lifetime relative		4	R	4	INT32	n/a	-
CH2 actual		5	R	4	INT32	n/a	-
CH2 startup relative		6	R	4	INT32	n/a	-
CH2 reset relative		7	R	4	INT32	n/a	-
CH2 lifetime relative		8	R	4	INT32	n/a	-
CH3 actual		9	R	4	INT32	n/a	-
CH3 startup relative		10	R	4	INT32	n/a	-
CH3 reset relative		11	R	4	INT32	n/a	-
CH3 lifetime relative		12	R	4	INT32	n/a	-

CHx actual

If the target is currently in the sensing window around the switching point, then it shows the current deviation in μm. If the target is outside of the sensing window, then it shows the minimum recorded deviation in μm.

CHx startup relative

Shows the stroke deviation of a given channel since the sensor startup in percentage of the channel’s stroke length.

CHx reset relative

Shows the stroke deviation of a given channel since the last Maintenance reset in percentage of the channel’s stroke length.

CHx lifetime relative

Shows the stroke deviation of a given channel since it was shipped in percentage of the channel’s stroke length. This value cannot be reset.