Limitations for SMM R_03-00-004

Incorrect display of counts when changing step size for EnDat linear encoders.

A bug exists in the Parameter Editor affecting the displayed counts for EnDat 2.2 linear encoders when the step size (resolution) parameter is modified.

When the step size is set to 1 nm, the displayed values are correct. However, for larger step sizes (e.g., 10 nm, 100 nm), the displayed counts (including counts per meter as well as position, velocity, and acceleration related values) are not scaled as expected when the resolution is changed and may appear inconsistent or incorrect.

Impact:

This issue affects displayed information only in the user interface. It does not impact internal computations, safety functions, or runtime behavior of the system. However, it may mislead users when verifying or interpreting configuration values.

Workaround:

Do not rely on the displayed counts when using step sizes greater than 1 nm. If necessary, calculate and verify the expected values manually based on the encoder resolution.

Restart the SMM if you download a new configuration which changes the used encoder protocols.

Restart the SMM when

• the current configuration already uses HDSL and/or EnDat 2.2 and
• you download a new configuration which adds or removes one of the encoder protocols.

Example: Restart the SMM, if the current configuration uses only HDSL and you download a new configuration which only uses EnDat 2.2.

No Safe Brake Test (SBT) for linear motors

Safe Brake Test is designed for rotary motors/brakes and thus does not support linear motors.

Speed limitation for all safe encoders

Rotary encoders: a max. speed of 30,000rpm must not be exceeded.

Linear encoders: depending on the resolution, the following speed must not be exceeded:

• 1nm res. / 8.38m/s
• 5nm res. / 41.9m/s
• 10nm res. / 83.8m/s

A safe EnDat 2.2 encoder cannot be used with a safe HIPERFACE DSL encoder

If an EnDat 2.2 encoder is configured as a safe feedback on one of the two axes, the other axis cannot use a safe encoder, such as HIPERFACE DSL.

HIPERFACE DSL EFx50 encoders are not supported.

The EFx50 encoder series is not supported and phased out by Sick.

Workaround: Use a more recent Hiperface-DSL encoder series.

Do not use FSoE Status Word bit "Error acknowledge status".

The status Word bit "Error acknowledge status" is set to true when either an I/O failure is detected, the safe encoder is not configured or the safe speed is not available. In case of an I/O failure, FSoE will send "FailSafeData" anyway. Therefore, this bit doesn't serve any purpose in real applications.

Workaround: Check for I/O failures using the FSoE state instead of the Status Word.

Position monitoring limits have to be less than half of the max. position with SOS/SLI/SDI.

When using position monitoring with functions that use relative position (SOS/SLI/SDI), the position limit parameters (upper and lower) have to be less than half of the max. position of the encoder.

Workaround: -

Position monitoring limits have to be less than half of the max. position with SLP/SCA and signed-range.

When using position monitoring with functions that use absolute position (SLP/SCA), the position limit parameters (upper and lower) have to be less than half of the max. position of the encoder when using a singed range. For an unsigned range, the position limit parameters have to be less than the max. position of the encoder.

Workaround: -

The deceleration ramp parameters for the safety functions SS1 (a_SS1), SS2 (a_SS2), SLS (a_SLS) and SSR (a_SSR) are using the defined velocity user unit per second instead of the defined acceleration user unit.

Example:
When the velocity user unit is rpm, the acceleration user unit is m/s² and a_SS1 is set to 1000, then the unit will be 1000 rpm/s instead of 1000 m/s².

Workaround: -

Reset the absolute position when a safe encoder is physically replaced by another safe encoder.

Reset the absolute position when:

• the safe encoder is physically replaced by another one (with the same or different model) and
• the application is using at least one of the SLP or SCA instances (the application then requires a valid absolute position to operate).