Siemens PAC1600
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.
- Protocol
- Modbus RTU
- Connection
- RS485
- Registers
- 36, read only
- Brand
- Siemens
- Last updated
Registers (36)
36 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| voltage_l1 | V | Read | |||
| voltage_l2 | V | Read | |||
| voltage_l3 | V | Read | |||
| current_l1 | A | Read | |||
| current_l2 | A | Read | |||
| current_l3 | A | Read | |||
| voltage_l1l2 | V | Read | |||
| voltage_l2l3 | V | Read | |||
| voltage_l3l1 | V | Read | |||
| active_power_l1 | W | Read | |||
| active_power_l2 | W | Read | |||
| active_power_l3 | W | Read | |||
| reactive_power_l1 | W | Read | |||
| reactive_power_l2 | W | Read | |||
| reactive_power_l3 | W | Read | |||
| frequency | Hz | Read | |||
| voltage | V | Read | |||
| voltage_ll | V | Read | |||
| active_power | W | Read | |||
| reactive_power | var | Read | |||
| active_consumption_energy | Wh | Read | |||
| active_production_energy | Wh | Read | |||
| reactive_consumption_energy | Wh | Read | |||
| reactive_production_energy | Wh | Read | |||
| active_consumption_energy_l1 | Wh | Read | |||
| active_production_energy_l1 | Wh | Read | |||
| reactive_consumption_energy_l1 | varh | Read | |||
| reactive_production_energy_l1 | varh | Read | |||
| active_consumption_energy_l2 | Wh | Read | |||
| active_production_energy_l2 | Wh | Read | |||
| reactive_consumption_energy_l2 | varh | Read | |||
| reactive_production_energy_l2 | varh | Read | |||
| active_consumption_energy_l3 | Wh | Read | |||
| active_production_energy_l3 | Wh | Read | |||
| reactive_consumption_energy_l3 | varh | Read | |||
| reactive_production_energy_l3 | varh | Read |
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Use cases
- Monitor per-phase active power to detect load imbalances across L1, L2, and L3 in real time.
- Track cumulative active consumption energy per phase to allocate costs across tenants or circuits.
- Alert on grid frequency deviations to identify upstream supply quality issues before equipment is affected.
- Compare active production energy against consumption energy totals to verify net metering figures over billing periods.
- Verify that reactive power stays within acceptable limits to spot power-factor issues before utility penalties apply.
Installation
Enable Modbus RTU on the PAC1600 by setting communication parameters P-20 through P-24 on the device front panel: configure slave address, baud rate, parity, and stop bits to match your bus.
Wire the PAC1600 RS485 terminals (A, B, and COM) to the ModbusCloud Gateway RS485 port using shielded twisted-pair cable; fit a 120-ohm termination resistor at each end of the bus if the PAC1600 is the last device on the segment.
In the ModbusCloud portal, add your Gateway, import the Siemens PAC1600 template with one click, and assign the slave unit ID that matches the address configured in step 1.
Spot-check the connection by confirming that voltage_l1, active_power, and frequency show live values in the portal dashboard; a reading of zero on all registers typically indicates a unit ID or baud rate mismatch.
Things to watch for
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.
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