Functions - Siemens 3UG4 User Manual

12.3

Functions

General functionality
Depending on the setting, the speed monitoring relays monitor a speed in revolutions per
minute (rpm) for overshoot (rpm▲), undershoot (rpm▼) or in range monitoring (rpm▲ and
rpm▼). Depending on their design, the devices are powered with a rated control supply
voltage of 24 V AC/DC or 24 to 240 V AC/DC supply voltage through terminals A1/A2.
The 3UG4651 speed monitoring relays have a display and are parameterized with three
keys.
You will find the setting ranges and factory settings of the available parameters in Chapter
"Operation (Page 312)."
You will find a description of the individual parameters in Chapter "Parameters (Page 363)."
Speed monitoring functions according to the principle of period duration measurement.
In the speed monitoring relay, the time interval between two consecutive rising edges of the
pulse encoder is measured and compared with the minimum and/or maximum permissible
period duration calculated from the set threshold values for the speed. Period duration
measurement detects a speed deviation after only two pulses.
By using up to ten pulse encoders distributed simultaneously across the range, the period
duration, and thus the response time, can be reduced. By taking account of the number of
sensors in the speed monitoring relay, the speed continues to be displayed in revolutions per
minute.
The number of pulses supplied by the pulse encoder can be defined with the help of entering
a scaling value (Scale). This allows the revolutions per minute to be read direct on the
display.
The speed monitoring relays have two different pulse inputs. Only one of these may be used!
A pnp-switching three-wire sensor for 0 V / +24 V DC pulses can be connected at terminal
IN1. It is supplied from the output relay via terminals 0V and 24V / with up to 50 mA. Use of a
mechanical pulse contact with an external DC supply of 4.5 to 30 V is also permissible at
terminal IN1.
Note
To detect the edges reliably, the pulses and pauses between pulses of the pulse encoders
used must be applied for at least 5 ms. A pause is detected when the voltage level < 1 V. A
pulse requires a minimum value of 4.5 V.
Alternatively, a two-wire NAMUR sensor supplied from terminal 8V2, or a mechanical
contact, can be connected at terminal IN2.
3UG4 / 3RR2 monitoring relays
Manual, 05/2016, NEB927043002000/RS-AC/004
3UG4651 speed monitoring relay
12.3 Functions
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