No register values appear even though the gateway connects.

The KSEM Modbus TCP slave is disabled by default. Log into the KSEM web interface, go to Modbus settings, open the Slave section, and switch on Enable TCP Slave. Without this step, the meter accepts the TCP connection but returns no data.

Integer and float register sets show different power values. Why?

The KSEM exposes two parallel register sets: an integer set (addresses 0 to 142) with separate consumption and production registers, and a float set (addresses 220 to 254) with signed net values. Both are valid. The float set at addresses 224, 234, 244, and 252 reports signed net power and is the more convenient source for feed-in detection.

Readings look correct but shift or scramble intermittently.

The KSEM documentation states that multi-register data points must be read in a single request to avoid misalignment between high and low words. If your polling logic reads individual 16-bit registers separately, switch to requesting both words of each uint32 or float32 in one Read Holding Registers call.

The meter connects via the Plenticore inverter proxy at port 1502. Should I use that?

The OpenEMS template targets the KSEM directly via its own LAN port at port 502, not the inverter proxy at port 1502. Use the KSEM IP address and port 502. If you also have the Plenticore connected, both paths can coexist but point to different unit IDs and register maps.

Free Modbus template: Kostal Plenticore KSEM

Name: Kostal Plenticore KSEM
Brand: Kostal
SKU: a0aea6a8-1092-4675-a995-269a8a006c88

The Kostal KSEM (KOSTAL Smart Energy Meter) is a three-phase bidirectional energy meter installed at the grid connection point of PV systems built around Kostal Plenticore inverters. Over Modbus TCP, this template reads the complete instantaneous power picture: total and per-phase active consumption and production power, reactive power for both directions, voltage, current, and grid frequency across two register sets. The float register set provides signed net active and reactive power per phase, which is particularly useful for real-time feed-in monitoring. ModbusCloud can log all channels continuously, giving installers and asset managers a full grid-interface dataset without additional hardware.

Registers (38)

38 read / 0 write

Name	Address	Function	Type	Unit	Access
active_consumption_power Total active power drawn from the grid, all phases, watts.	0	FC03	uint32	W	R
active_production_power Total active power fed into the grid, all phases, watts.	2	FC03	uint32	W	R
active_consumption_reactive_power Total reactive power consumed from the grid, all phases.	4	FC03	uint32	W	R
active_production_reactive_power Total reactive power delivered to the grid, all phases.	6	FC03	uint32	W	R
frequency_a Grid frequency measured at the meter, hertz, integer format.	26	FC03	int32	Hz	R
active_consumption_power_l1 Active power consumed from the grid on phase L1.	40	FC03	uint32	W	R
active_production_power_l1 Active power fed into the grid on phase L1.	42	FC03	uint32	W	R
active_consumption_reactive_power_l1 Reactive power consumed from the grid on phase L1.	44	FC03	uint32	W	R
active_production_reactive_power_l1 Reactive power delivered to the grid on phase L1.	46	FC03	uint32	W	R
current_l1_a RMS current on phase L1, amperes, integer register set A.	60	FC03	uint32	A	R
voltage_l1_a RMS voltage on phase L1, volts, integer register set A.	62	FC03	uint32	V	R
active_consumption_power_l2 Active power consumed from the grid on phase L2.	80	FC03	uint32	W	R
active_production_power_l2 Active power fed into the grid on phase L2.	82	FC03	uint32	W	R
active_consumption_reactive_power_l2 Reactive power consumed from the grid on phase L2.	84	FC03	uint32	W	R
active_production_reactive_power_l2 Reactive power delivered to the grid on phase L2.	86	FC03	uint32	W	R
current_l2_a RMS current on phase L2, amperes, integer register set A.	100	FC03	uint32	A	R
voltage_l2_a RMS voltage on phase L2, volts, integer register set A.	102	FC03	uint32	V	R
active_consumption_power_l3 Active power consumed from the grid on phase L3.	120	FC03	uint32	W	R
active_production_power_l3 Active power fed into the grid on phase L3.	122	FC03	uint32	W	R
active_consumption_reactive_power_l3 Reactive power consumed from the grid on phase L3.	124	FC03	uint32	W	R
active_production_reactive_power_l3 Reactive power delivered to the grid on phase L3.	126	FC03	uint32	W	R
current_l3_a RMS current on phase L3, amperes, integer register set A.	140	FC03	uint32	A	R
voltage_l3_a RMS voltage on phase L3, volts, integer register set A.	142	FC03	uint32	V	R
frequency_b Grid frequency, hertz, float register set B.	220	FC03	float32	Hz	R
current_l1_b RMS current on phase L1, amperes, float register set B.	222	FC03	float32	A	R
active_power_l1 Net active power on phase L1, positive consumption, float.	224	FC03	float32	W	R
reactive_power_l1 Net reactive power on phase L1, float register set B.	226	FC03	float32	W	R
voltage_l1_b RMS voltage on phase L1, volts, float register set B.	230	FC03	float32	V	R
current_l2_b RMS current on phase L2, amperes, float register set B.	232	FC03	float32	A	R
active_power_l2 Net active power on phase L2, positive consumption, float.	234	FC03	float32	W	R
reactive_power_l2 Net reactive power on phase L2, float register set B.	236	FC03	float32	W	R
voltage_l2_b RMS voltage on phase L2, volts, float register set B.	240	FC03	float32	V	R
current_l3_b RMS current on phase L3, amperes, float register set B.	242	FC03	float32	A	R
active_power_l3 Net active power on phase L3, positive consumption, float.	244	FC03	float32	W	R
reactive_power_l3 Net reactive power on phase L3, float register set B.	246	FC03	float32	W	R
voltage_l3_b RMS voltage on phase L3, volts, float register set B.	250	FC03	float32	V	R
active_power Total net active power across all three phases, float.	252	FC03	float32	W	R
reactive_power Total net reactive power across all three phases, var, float.	254	FC03	float32	var	R