21
The control module measures three phase cur-
rents, three phase-to-phase voltages, active and
reactive power and energy. For energy pulse
counting the control module includes a pulse
counter input. Other measurements require an
optional measuring module which rectifies and
processes the analog measuring signals.
Measuring module SPTM 8A1 (optional)
The measuring module type SPTM 8A2 is used
for processing the phase current and phase-to-
phase voltage signals. This module also includes
two mA inputs which are used for measuring
active and reactive power via external measuring
transducers. The module rectifies the phase
current and the phase-to-phase voltage signals
and converts the mA signals to voltage signals
for further transfer to the control module.
Scaling of measured
values
3I (~)
3U (~)
P (mA)
Q (mA)
Q (U)
P (U)
3I (-)
3U (-)
SPTM 8A1
I
U
I
U
Fig. 14. Block diagram of measuring module
SPTM 8A1.
Measuring module SPTM 6A2 (optional)
The optional measuring module type SPTM
6A2 is used for processing phase current and
phase-to-phase voltage signals. This module also
includes the electronics required to form, using
internal current and voltage signals, measuring
signals corresponding to active and reactive
power, according to the Aron-connection prin-
ciple. The measuring module SPTM 6A2 recti-
fies the phase current and the phase-to-phase
voltage signals and routes them to the control
module together with the signals proportional
to the active and reactive power.
3I (~)
3U (~)
Q (-)
P (-)
3I (-)
3U (-)
SPTM 6A2
3UI x
cos
ϕ
3UI x
sin
ϕ
3
2
2
2
Fig. 15. Block diagram of measuring module
SPTM 6A2.
Measuring module SPTM 6A3 (optional)
The measuring module type SPTM 6A3 is used
for handling phase current and phase-to-phase
voltage signals. This module also includes the
electronics required to form signals which, us-
ing the internal current and voltage signals,
generates signals corresponding to the active
and reactive power. The power measurement is
based on one voltage and two current signals.
The voltage to be used and the corresponding
currents can be selected with switches. The
measuring module SPTM 6A3 rectifies the phase
current and phase-to-phase voltage signals and
transmits them to the control module together
with the signals proportional to active and reac-
tive power.
3I (~)
3U (~)
Q (-)
P (-)
3I (-)
3U (-)
SPTM 6A3
3UI x
cos
ϕ
3UI x
sin
ϕ
1
2
2
1
Fig. 16. Block diagram of measuring module
SPTM 6A3.
Energy can be measured in two ways; by using
input 11 as a pulse counter or by integrating the
measured power. In the former case an external
energy meter with pulse output is required.
