6 VersiSafe Speed
6. Functions
The auxiliary voltage is connected to terminals A1-A2. he equipment can be configured via the
display and the setting keys on the front plate. Terminals E1a, E1b, E2L, E2H, E3L and E3H form
the measuring input.
For low voltages the measuring voltage is connected to E1a-E2L and E1b-E3L and for higher
voltages to E1a-E2H and E1b-E3H (see section technical data).
When monitoring single phase AC voltage, it is recommended to connect the terminals E1a-E2L
or E1a-E2H directly to the inverter, the terminals E1b-E3L or E1b-E3H directly to the motor
connection terminals. Seperate wires in separate cables with space to each other have to be
used for each of the frequency inputs. When monitoring 3-pase AC voltages it is recommended to
wire these terminals directly to the motor connection terminals.
The input frequency is compared to the setting value. As the device measures the cycle duration
the fastest frequency measurement is possible. Should the over-frequency function be set, then
the output relay will switch to the alarm mode, when the set response parameter is over-
exceeded longer than the parametered alarm-delay function (tV). Should the frequency fall again
below the response parameter, minus the set hysteresis, the output relay will be activated after
the expiry of the reset-delay time period (tF) and return to its pre-set permitted supervisory state.
As regards the under-frequency function, the output relay will switch to the alarm mode, when the
set response parameter is under-exceeded longer than the parametered alarm-delay function (tV)
time period. As soon as the frequency return to the range governed by the response parameter,
plus the set hysteresis, then the output relay will again return to the pre-set permitted state after
the expiry of the reset-delay time period (tF).
In the „internal window function mode“, the output relay will switch to the alarm setting when the
frequency exceed the pre-set permitted range of the response parameter. Once the frequency
again return within the range of both the upper- and lower response parameters, minus and/or
plus the pre-set hysteresis values (upper response parameter minus- and/or the lower response
parameter plus -the relative hysteresis values), then the output relay will again switch back to the
pre-set permitted range after the expiry of the reset-delay time period (tF).
In the „external window function mode“, the monitoring function acts inversely to the „internal
window function“. Should the manual reset function be activated, then the output relay continues
to remain in the alarm setting when the frequency return to the pre-set permitted range. A
resetting of the saved parameter is possible when the reset input is activated or the auxiliary
voltage is shutdown. When a start-up delay time period (tA) is set, then the set start-up delay time
period will initially expire as soon as the auxiliary voltage of the equipment is switched-on and the
‘RF’ feedback circuit is closed. The start-up delay time period will also expire after a reset of the
manual reset mode. During this time period, a frequency evaluation is disabled and the output
relays remain at the pre-set permitted setting. The start-up delay function can, for example
override an alarm message during the start-up stage of a generator or electric motor. Should,
after a reset (in the manual reset mode), the feedback circuit not be closed, then the equipment
will go into a safe error state. With correct connection it is possible to realise with the UH 6937 the
safety functions STO (Safe Torque Off), SOS (Safe Operating Stop), SLS (Safely Limited Speed),
SSM (Safe Speed Monitor) and SSR (Safe Speed Range) according to EN 61800-5-2. The actual
realisation of the safety functions has to be validated in each application of the product for safety
aspects.
