All registers return zero or NaN. What is wrong?

The EMpro family returns float32 values spanning two consecutive 16-bit registers. Confirm your gateway is configured to read 2 holding registers per point (count 2) using function code 3. A count of 1 will yield an incomplete float and produce garbage or zero readings.

The gateway connects but no data appears in the portal.

Check that the Modbus unit ID in the portal matches the slave address configured on the device. Many PhoenixContact EMpro units ship with unit ID 255. Also confirm port 502 is reachable: firewall rules on managed switches can silently block Modbus TCP traffic.

Phase voltage values look correct but active power reads near zero.

Active power registers (32790, 32798, 32800, 32802) report signed float32 values. If current transformer polarity is reversed on one or more phases, positive and negative contributions cancel out. Verify CT orientation matches the documented wiring direction in the device manual.

Cumulative energy counters reset unexpectedly after a power cycle.

Some firmware versions of the EMpro series store energy totals in volatile memory until a configurable save interval elapses. Check the device web interface for an energy counter persistence or auto-save setting and ensure the device is not being hard-reset during commissioning.

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Registers (15)

15 read / 0 write

Name	Address	Function	Type	Unit	Access
voltage_l1 Phase L1 voltage, in volts.	32774	FC03	float32	V	R
voltage_l2 Phase L2 voltage, in volts.	32776	FC03	float32	V	R
voltage_l3 Phase L3 voltage, in volts.	32778	FC03	float32	V	R
frequency Grid frequency, in hertz, typically 50 or 60.	32780	FC03	float32	Hz	R
current_l1 Phase L1 current, in amperes.	32782	FC03	float32	A	R
current_l2 Phase L2 current, in amperes.	32784	FC03	float32	A	R
current_l3 Phase L3 current, in amperes.	32786	FC03	float32	A	R
current Total three-phase current, in amperes.	32788	FC03	float32	A	R
active_power Total three-phase active power, in watts.	32790	FC03	float32	W	R
active_power_l1 Phase L1 active power, in watts.	32798	FC03	float32	W	R
active_power_l2 Phase L2 active power, in watts.	32800	FC03	float32	W	R
active_power_l3 Phase L3 active power, in watts.	32802	FC03	float32	W	R
voltage Average or system voltage, in volts.	32829	FC03	float32	V	R
active_consumption_energy Cumulative active energy consumed, in watt-hours.	33024	FC03	float32	Wh	R
active_production_energy Cumulative active energy produced or exported, in watt-hours.	33030	FC03	float32	Wh	R