User Manual

3UG4651 speed monitoring relay
13.3 Functions
3UG4 / 3RR2 monitoring relays
298 Manual, 02/2013, NEB927043002000/RS-AA/002
Monitoring
Startup delay
To be able to start a drive, the output relay switches to the correct state during the ON-delay
time (onDel) depending on the selected open-circuit principle or closed-circuit principle, even
if the measured value is still under the set value.
The ON-delay time is started either by switching on the rated control supply voltage or, if the
rated control supply voltage is present, by actuating the relevant contact (e.g. auxiliary
contact of a contactor).
Tripping delay
If the measured value overshoots or undershoots the set threshold after expiry of the ON-
delay time (onDel), the set tripping delay time (Del) and the relay symbol will flash. After
expiry of this time, the output relays change the switching state. On the display, the current
measuring value and the symbol for undershoot or overshoot flash.
Operating mode with/without enable contact
In the operating mode without enable contact (terminal EN = Enable not connected), the
output relay responds when the rated control supply voltage is switched in accordance with
the set closed-circuit principle NC or open-circuit principle NO (relay control is inverted to the
closed-circuit principle NC), and the ON-delay time (onDel) is started, provided the lower
threshold is not at OFF. If the speed reaches the lower threshold value plus the set
hysteresis during this time, the ON-delay time is stopped and normal monitoring begins. If
this value has not yet been reached after expiry of the ON-delay time, the output
relay switches to the fault state depending on the selected relay switching behavior.
For the functioning of the operating mode with enable contact (terminal EN = Enable is
connected to terminal 24V with an isolated NC contact), a rated control supply voltage must
be present at terminals A1 and A2 on the monitoring relay. Only when this NC contact is
actuated will the ON-delay time (onDel) and the drive (with a second contact, for example)
be started.
You will find the switching states of the output relay below in the section entitled "Function
diagrams" and in Chapter "Diagnostics (Page 301)."