SIEB & MEYER SD2, Translation Of The Original Instructions

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5 Parameterization of the Limit
Frequency
In order to use the safety functions you must specify the respective limit frequency
protected against unauthorized access. There are 2 options for this purpose:
1. Set limit frequency in the parameter file
2. Set limit frequency via fieldbus
The user must protect the parameter file against unauthorized changes.
Set limit frequency in the parameter file
The user sets the limit frequency to a fix value in the parameter file of the drive. The
user must protect the parameter file against unauthorized changes. For this purpose,
the user assigns a password in the software
drivemaster2. Thus, only users knowing
the password can change and overwrite the parameter file.
For more information on the parameterization of the drive refer to the manual “drive‐
master2 - User Manual”.
Set limit frequency via fieldbus
Setting the limit frequency via fieldbus is required in automated processes, when the
limit value depends on the status of the system (tool/access control). In this case, the
user must protect the program of the safety PLC against unauthorized access.
The limit frequency is set via fieldbus by a higher-ranking PLC. The PLC can read the
parameter back at any time. In order to ensure the correct parameterization, we recom‐
mend reading the parameter cyclically back.
5.1 System-inherent deviation of the measurable
output frequency of the converter
When measuring the output frequency of the converter, a system-inherent deviation
occurs through the quantization of the measured values, which is due to the time
measurement and the 1/T calculation shown below. The reciprocal of the switching
frequency of the converter is the smallest measurable unit of time. Moreover, the
measurement accuracy is subject to tolerances.
Formula for calculating the system-inherent deviation
The following formulas apply for the system-inherent deviation:
▶ Switching frequency of the converter: f
pwm
= 16 kHz
▶ Minimum measuring resolution: 62.5 µs
▶ Output frequency of the converter: f
out
= 1 - 2000 Hz
Absolute deviation
f =
err
− f
out
f
pwm
Integer
f
pwm
f
out
( )
W
Parameterization of the Limit Frequency
Drive System SD2 - Safety Functions SFM / SLOF 23
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