SMA SUNNY CENTRAL 800CP XT - Reactive Power Control; No Reactive Power Control: off Mode; Reactive Power Control with Setpoint Command Via Modbus Protocol: Varctlcom Mode; Reactive Power Control with Setpoint Command Via Modbus Protocol: Pfctlcom Mode

10 Function Description
SMA Solar Technology AG
User Manual 95SCCPXT-E7-BA-en-58
The analog value is converted to a setpoint for power limitation. Here, the parameter Pmax forms the end point of the
linear characteristic curve.
10.3.3 Reactive Power Control
10.3.3.1 No Reactive Power Control: Off Mode
The reactive power setpoint is limited to 0kVAr. This setpoint cannot be controlled.
10.3.3.2 Reactive Power Control with Setpoint Command via Modbus Protocol:
VArCtlCom Mode
The reactive power setpoint is received by the communication unit and transmitted to the inverter. The setpoint is
transmitted as a percentage value and converted to kVAr in the device. If the inverter has not received any signal for
five minutes, the error message Q-VArModFailStt will be displayed.
10.3.3.3 Reactive Power Control with Setpoint Command via Modbus Protocol:
PFCtlCom Mode
The reactive power setpoint is received by the communication unit and transmitted to the inverter. The setpoint is
transmitted as a displacement power factor cosφ. If the inverter has not received any signal for the last five minutes, an
error message will be displayed in the instantaneous value Q-VArModFailStt.
10.3.3.4 Reactive Power Control with Absolute Value: VArCnst Mode
The reactive power setpoint is set via the parameter Q-VAr. The parameter Q-VAr is permitted to be within the range
from ‒Qmax to+Qmax.
10.3.3.5 Reactive Power Control as a Percentage of the Nominal Power: VArCnstNom
Mode
The parameter Q-VArNom is used to set the reactive power setpoint in%. The parameter Q-VArNom refers to
Pmax. If the calculated amount of reactive power exceeds the predefined value of Qmax, the power will be limited
to Qmax. If the calculated amount of reactive power falls below the predefined value of ‒Qmax, the power will be
limited to ‒Qmax.
10.3.3.6 Reactive Power Setpoint via Standard Signal: VArCnstNomAnIn Mode
The reactive power setpoint is set at the input terminals for the setpoints via an analog signal. This is usually
implemented by a ripple control signal. The analog value is converted into a reactive power setpoint. The electrical
current strength of the connected signal determines the setpoint. The analog measured values must be between
4mAand19mA. If the analog signal is less than 2mA, an error message will be displayed in the instantaneous value
Q‑VArModFailStt.
Signal Power limit Description
<2mA Last valid mean value or 0kVAr after
restart
Signal is in the invalid range.
2 mA to 4 mA
Qmax / underexcited
The maximum amount of negatively excited reactive
power is fed in.
4mA
Qmax / underexcited
Start point of the characteristic curve
The maximum amount of negatively excited reactive
power is fed in.