The gateway connects but all register values read zero. Why?

The most common cause is a slave address mismatch: the unit ID in the ModbusCloud portal must exactly match parameter P-20 on the PAC1600. Also verify that baud rate and parity configured in parameters P-21 and P-22 match the gateway serial port settings. A single mismatch causes silent read failures.

Energy counter registers at address 6687 return garbage or timeout errors.

The PAC1600 register map has a large address gap between the instantaneous power registers (below address 60) and the energy counters (starting at 6687). Some Modbus masters fail if a single read request spans that gap. Configure the template to read the energy block as a separate request, not in one continuous scan from address 1.

Phase voltage values look correct but line-to-line registers seem wrong.

The voltage_l1l2, voltage_l2l3, and voltage_l3l1 registers in this template have no unit field set. They carry the same physical unit (volts) as the phase registers but the scaling factor in the PAC1600 register map applies equally. Confirm your display tool is not applying a second scaling factor to those registers.

RS485 communication drops intermittently on a multi-device bus.

Intermittent RS485 failures are nearly always caused by missing bus termination or reversed A/B polarity. Fit 120-ohm resistors at both physical ends of the cable run, verify the shield is grounded at one end only, and confirm that A connects to A and B to B throughout the chain. Keep the serial cable away from power conductors.

Free Modbus template: Siemens PAC1600

Name: Siemens PAC1600
Brand: Siemens
SKU: 183e1859-7bfa-4e3b-ad2d-96262882a5b4

The Siemens PAC1600 is a DIN-rail energy meter in the SENTRON family, designed for measuring electrical variables in low-voltage AC distribution panels. This ModbusCloud template reads the full set of registers the meter exposes over Modbus RTU: per-phase voltages (L-N and L-L), currents, active and reactive power, grid frequency, and cumulative energy counters for active and reactive consumption and production, broken down by total and per individual phase. Connecting the PAC1600 to the ModbusCloud Gateway gives installers and facility managers continuous visibility into load balance, energy flows, and billing-relevant totals without manual meter reads.

Registers (36)

36 read / 0 write

Name	Address	Function	Type	Unit	Access
voltage_l1 Phase L1 to neutral voltage, in volts.	1	FC03	uint32	V	R
voltage_l2 Phase L2 to neutral voltage, in volts.	3	FC03	uint32	V	R
voltage_l3 Phase L3 to neutral voltage, in volts.	5	FC03	uint32	V	R
current_l1 Phase L1 current, in amperes.	7	FC03	uint32	A	R
current_l2 Phase L2 current, in amperes.	9	FC03	uint32	A	R
current_l3 Phase L3 current, in amperes.	11	FC03	uint32	A	R
voltage_l1l2 Line-to-line voltage between L1 and L2.	13	FC03	uint32	V	R
voltage_l2l3 Line-to-line voltage between L2 and L3.	15	FC03	uint32	V	R
voltage_l3l1 Line-to-line voltage between L3 and L1.	17	FC03	uint32	V	R
active_power_l1 Active power on phase L1, in watts.	19	FC03	int32	W	R
active_power_l2 Active power on phase L2, in watts.	21	FC03	int32	W	R
active_power_l3 Active power on phase L3, in watts.	23	FC03	int32	W	R
reactive_power_l1 Reactive power on phase L1, in var.	25	FC03	int32	W	R
reactive_power_l2 Reactive power on phase L2, in var.	27	FC03	int32	W	R
reactive_power_l3 Reactive power on phase L3, in var.	29	FC03	int32	W	R
frequency Grid frequency, in hertz.	49	FC03	int32	Hz	R
voltage Average phase-to-neutral voltage across all phases.	51	FC03	int32	V	R
voltage_ll Average line-to-line voltage across all phase pairs.	53	FC03	int32	V	R
active_power Total three-phase active power, in watts.	57	FC03	int32	W	R
reactive_power Total three-phase reactive power, in var.	59	FC03	int32	var	R
active_consumption_energy Cumulative total active energy consumed, in watt-hours.	6687	FC03	uint32	Wh	R
active_production_energy Cumulative total active energy exported, in watt-hours.	6689	FC03	uint32	Wh	R
reactive_consumption_energy Cumulative total reactive energy consumed, in watt-hours.	6691	FC03	uint32	Wh	R
reactive_production_energy Cumulative total reactive energy exported, in watt-hours.	6693	FC03	uint32	Wh	R
active_consumption_energy_l1 Cumulative active energy consumed on phase L1.	6707	FC03	uint32	Wh	R
active_production_energy_l1 Cumulative active energy exported on phase L1.	6709	FC03	uint32	Wh	R
reactive_consumption_energy_l1 Cumulative reactive energy consumed on phase L1.	6711	FC03	uint32	varh	R
reactive_production_energy_l1 Cumulative reactive energy exported on phase L1.	6713	FC03	uint32	varh	R
active_consumption_energy_l2 Cumulative active energy consumed on phase L2.	6727	FC03	uint32	Wh	R
active_production_energy_l2 Cumulative active energy exported on phase L2.	6729	FC03	uint32	Wh	R
reactive_consumption_energy_l2 Cumulative reactive energy consumed on phase L2.	6731	FC03	uint32	varh	R
reactive_production_energy_l2 Cumulative reactive energy exported on phase L2.	6733	FC03	uint32	varh	R
active_consumption_energy_l3 Cumulative active energy consumed on phase L3.	6747	FC03	uint32	Wh	R
active_production_energy_l3 Cumulative active energy exported on phase L3.	6749	FC03	uint32	Wh	R
reactive_consumption_energy_l3 Cumulative reactive energy consumed on phase L3.	6751	FC03	uint32	varh	R
reactive_production_energy_l3 Cumulative reactive energy exported on phase L3.	6753	FC03	uint32	varh	R