GE Multilin PQM/PQMII power quality meter

Register map(s) for this device, with a note of how far each has been checked. Addresses are 0-based, as on the wire. Scale and byte order are confirmed only at the hardware-verified rung.

coherence-checked

Round-trips through a real Modbus stack with no overlapping addresses and a word-order-sensitive codec — the map is internally coherent and wire-decodable. Does NOT prove byte-order or scaling match a real device: the emulator is seeded from the map's own types, so a uniformly wrong byte-order still round-trips. Only hardware-verified confirms byte-order/scale on the wire.

point	address (0-based)	type	scale	unit
Product Device Code	0	U16	1
Hardware Version Code	1	U16	1
Main Software Version Code	2	U16	1
Modification File Number 1	3	U16	1
Boot Software Version Code	4	U16	1
Product options	6	U16	1
CPU Speed	11	U16	1
Serial Number Character 1 and 2	32	U16	1
Serial Number Character 3 and 4	33	U16	1
Serial Number Character 5 and 6	34	U16	1
Serial Number Character 7 and 8	35	U16	1
Manufacture Month/Day	48	U16	1
Manufacture Year	49	U16	1
Calibration Month/Day	50	U16	1
Calibration Year	51	U16	1
Command Function Code	128	U16	1
Command Operation Code	129	U16	1
Command Data 1	130	U16	1
Command Data 2	131	U16	1
Command Data 3	132	U16	1
Command Data 4	133	U16	1
Command Data 5	134	U16	1
Command Data 6	135	U16	1
Time Hours/Minutes	240	U16	1
Time Seconds	241	U16	1
Date Month/Day	242	U16	1
Date Year	243	U16	1
Switch Input Status	512	U16	1
LED Status Flags	513	U16	1
LED Attribute Flags	514	U16	1
Output Relay Status Flags	515	U16	1
Alarm Active Status Flags 1	516	U16	1
Alarm Active Status Flags 2	518	U16	1
Alarm Active Status Flags 3	520	U16	1
General Status	540	U16	1
Time - Hours/Minutes	560	U16	1
Time - Seconds	561	U16	1
Time - Month/Day	562	U16	1
Time Year	563	U16	1
Phase A Current	576	U16	1	A
Phase B Current	577	U16	1	A
Phase C Current	578	U16	1	A
Average Current	579	U16	1	A
Neutral Current	580	U16	1	A
Current Unbalance	581	U16	0.1	%
Phase A Current - Minimum	582	U16	1	A
Phase B Current - Minimum	583	U16	1	A
Phase C Current - Minimum	584	U16	1	A
Neutral Current - Minimum	585	U16	1	A
Voltage Van	640	U32BE	1	V
Voltage Vbn	642	U32BE	1	V
Voltage Vcn	644	U32BE	1	V
Average Phase Voltage	646	U32BE	1	V
Voltage Vab	648	U32BE	1	V
Voltage Vbc	650	U32BE	1	V
Voltage Vca	652	U32BE	1	V
Average Line Voltage	654	U32BE	1	V
Voltage Unbalance	656	U16	0.1	%
Voltage Van - Minimum	657	U32BE	1	V
Voltage Vbn - Minimum	659	U32BE	1	V
Ic Phasor Angle	748	U16	1	° lag
3 Phase Real Power	752	I32BE	0.01	kW
3 Phase Reactive Power	754	I32BE	0.01	kvar
3 Phase Apparent Power	756	U32BE	0.01	kVA
3 Phase Power Factor	758	I16	0.01	PF
Phase A Real Power	759	I32BE	0.01	kW
Phase A Reactive Power	761	I32BE	0.01	kvar
Phase A Apparent Power	763	U32BE	0.01	kVA
Phase A Power Factor	765	I16	0.01	PF
Phase B Real Power	766	I32BE	0.01	kW
Phase B Reactive Power	768	I32BE	0.01	kvar
Phase B Apparent Power	770	U32BE	0.01	kVA
Phase B Power Factor	772	I16	0.01	PF
Phase C Real Power	773	I32BE	0.01	kW
Phase C Reactive Power	775	I32BE	0.01	kvar
Phase C Apparent Power	777	U32BE	0.01	kVA
Phase C Power Factor	779	I16	0.01	PF
3 Phase Real Power - Minimum	780	I32BE	0.01	kW
3 Phase Reactive Power - Minimum	782	I32BE	0.01	kvar
3 Phase Positive Real Energy Used	976	U32BE	1	kWh
3 Phase Negative Real Energy Used	978	U32BE	1	kWh
3 Phase Positive React. Energy Used	980	U32BE	1	kvarh
3 Phase Neg Reactive Energy Used	982	U32BE	1	kvarh
3 Phase Apparent Energy Used	984	U32BE	1	kVAh
3 Phase Energy Used in Last 24 h	986	U32BE	1	kWh
3 Phase Energy Cost Since Reset	988	U32BE	0.01	$
Phase A Current Demand	1024	U16	1	A
Phase B Current Demand	1025	U16	1	A
Phase C Current Demand	1026	U16	1	A
Neutral Current Demand	1027	U16	1	A
3 Phase Real Power Demand	1028	I32BE	0.01	kW
3 Phase React Power Demand	1030	I32BE	0.01	kvar
3 Phase Apparent Power Demand	1032	U32BE	0.01	kVA
Phase A Current Demand - Maximum	1034	U16	1	A
Phase B Current Demand - Maximum	1035	U16	1	A
Phase C Current Demand - Maximum	1036	U16	1	A
Frequency	1088	U16	0.01	Hz
Frequency Minimum	1089	U16	0.01	Hz
Frequency Maximum	1090	U16	0.01	Hz
Phase A Current THD	1144	U16	0.1	%
Phase B Current THD	1145	U16	0.1	%
Phase C Current THD	1146	U16	0.1	%
Neutral Current THD	1147	U16	0.1	%
Voltage Van THD	1148	U16	0.1	%
Voltage Vbn THD	1149	U16	0.1	%
Voltage Vcn THD	1150	U16	0.1	%
Voltage Vab THD	1151	U16	0.1	%
Voltage Vbc THD	1152	U16	0.1	%
Meter ID characters 1 and 2	4096	U16	1
Default Message Time	4112	U16	0.1	min
Serial Communication Address	4120	U16	1
Modbus Baud Rate for RS485 COM1	4121	U16	1
Parity for RS485 COM1	4122	U16	1
Current Demand Calculation Type	4144	U16	1
Current Demand Time Interval	4145	U16	1	minutes
Phase CT Primary	4176	U16	1	A
Neutral Current Sensing	4177	U16	1
Neutral CT Primary	4178	U16	1	A
VT Wiring	4179	U16	1
VT Ratio	4180	U16	0.1	ratio
VT Nominal Secondary Voltage	4181	U16	1	V
Nominal Direct Input Voltage	4182	U16	1	V
Nominal Frequency	4183	U16	1	Hz
CT Wiring	4184	U16	1
Alarm Relay Operation	4360	U16	1
Alarm Relay Activation	4361	U16	1
Phase Overcurrent Activation	4390	U16	1
Phase Undercurrent Relay	4392	U16	1
Phase Undercurrent Level in Amps	4393	U16	1	A
Phase Undercurrent Delay	4394	U16	0.1	s
Power Alarms Level Base Units	4455	U16	1
Positive Real Power Relay	4456	U16	1
Positive Real Power Level in kW	4457	U16	1	kW
Positive Real Power Delay	4458	U16	0.1	s
Current/Voltage Simulation	4552	U16	1
Current/Voltage Simulation Time	4553	U16	1	min
Phase A Current	4554	U16	1	A
Log 1 Interval	4704	U32BE	1	s
Log 1 Mode	4708	U16	1
Log Size Determination	4710	U16	1
Log 1 Size	4711	U16	1	%
Ia Log Assignment	4720	U16	1
Product Options Upgrade	4848	U16	1
Record Selector	4896	U16	1
Sag Level % Nominal	4897	U16	1	%
Swell Level % Nominal	4898	U16	1	%

link settings as documented (unverified): RTU; default 9600 8N1; unit ID 1; FC 03,04,05,06,07,08,16; Up to 32 slaves can be daisy-chained on a single communication channel.

bench facts as documented (unverified)

terminals	each '+' terminal of every device must be connected together
A/B polarity	Polarity is important in RS485 communications
termination	terminating network installed at each end of the link... 120 ohm resistor in series with a 1 nF ceramic capacitor when used with Belden 9841 RS485 wire
connector	2-wire RS485 and 9-pin RS232 interfaces
shield/ground	Shielded wire should always be used to minimize noise.
max registers/read	125
broadcast	supported
protocol notes	Modbus allows up to a maximum of 60 holding registers to be stored in one transmission.
model register	0000
serial register	0020
firmware register	0002
FC 43 device ID	not supported
doc revision	2.2x
firmware applicability	2.2x

field reports — community-sourced, unverified (checked 2026-06-11)

When reading 32-bit unsigned long integers (such as energy registers) via Modbus, SCADA systems like Citect may require manual word-swapping or custom data type configuration because the PQMII stores 32-bit values across two consecutive 16-bit registers (high-order register first, then low-order register). [source]
confirmed: Baud rates [1200, 2400, 4800, 9600, 19200] with default 9600, parity N, stop bits 1, framing RTU, and default unit ID 1 — confirmed by GE Multilin PQMII Communications Guide (Section 1.3 & Memory Map)
confirmed: Supported Modbus function codes [3, 4, 5, 6, 7, 8, 16] — confirmed by GE Multilin PQMII Communications Guide (Section 2.1)
confirmed: Up to 32 slaves can be daisy-chained on a single communication channel — confirmed by GE Multilin PQMII Communications Guide (Section 1.1)
confirmed: Physical interface uses 2-wire RS485 and 9-pin RS232 — confirmed by GE Multilin PQMII Communications Guide (Section 1.2)
confirmed: Polarity is important in RS485 communications: each '+' terminal of every device must be connected together — confirmed by GE Multilin PQMII Communications Guide (Section 1.2)
confirmed: Shielded wire should always be used to minimize noise — confirmed by GE Multilin PQMII Communications Guide (Section 1.2)
confirmed: Terminating network of 120 ohm resistor in series with a 1 nF ceramic capacitor at each end of the link — confirmed by GE Multilin PQMII Communications Guide (Section 1.2)
confirmed: Broadcast supported via Function Code 05h — confirmed by GE Multilin PQMII Communications Guide (Section 2.4)

The trust ladder

Each rung states what it proved and what it did not. Gray until proven; green is earned by hardware only.

generated — A prompt produced it. Unproven — anyone can regenerate this.
structure-verified — Decode path is structurally sound (addresses, widths, finite values). Does NOT prove word order or scaling.
coherence-checked — Round-trips through a real Modbus stack with no overlapping addresses and a word-order-sensitive codec — the map is internally coherent and wire-decodable. Does NOT prove byte-order or scaling match a real device: the emulator is seeded from the map's own types, so a uniformly wrong byte-order still round-trips. Only hardware-verified confirms byte-order/scale on the wire.
hardware-verified (software-key) x1 — Matched a real device with operator-attested readings as ground truth — the only rung that confirms word order + scaling on the wire.

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