P1 Modbus load balancer

Modbus registers

Register	R/W	Description	Resolution	Unit	Default
1000	RW	Override the current load balancer limit (applied directly)	0.001	A	16 A
1001	R	The current limit decided by the load balancer	0.001	A
1002	R	The current load balancer state
1010	RW	The maximum charger current of the charger	0.001	A	16 A
1011	RW	Number of phases			3
1012	RW	Alarm limit current	0.001	A	24 A
1013	RW	Alarm limit wait time	1	second	1 s
1014	RW	Alarm limit current change amount	0.001	A	12.5A
1015	RW	Upper limit current	0.001	A	22 A
1016	RW	Upper limit wait time	1	second	5 s
1017	RW	Upper limit current change amount	0.001	A	1 A
1018	RW	Lower limit current	0.001	A	19 A
1019	RW	Lower limit wait time	1	second	1 s
1020	RW	Lower limit current change amount	0.001	A	1 A
1021	RW	Fallback limit	0.001	A	0 A
1022	RW	Fallback limit time	1	second	30 s
1090	W	Change the modbus server address			10
1091	W	Save and apply configuration (write 1)
1092	W	Restore defaults (write 1)

The defaults are bases on an 11 kW charger on an 3 phase 25 A grid connection.

Load balancer state

State	Description	LED Indication
0	Normal	._______ (1 pulse per second)
1	Lower limit	._._____ (2 pulses per second)
2	Upper limit	._._.___ (3 pulses per second)
3	Alarm limit	._._._._ (4 pulses per second)
4	Fallback/Error	----____ (0.5 sec on, 0.5 sec off)

diagslave -m rtu -b 9600 -p none /dev/ttyUSB0 modpoll -a 1 -0 -r 1000 -t 4 -1 -b 9600 -p none /dev/ttyACM1

Schematic and PCB are available on https://oshwlab.com/timstegeman/p1_modbus_loadbalancer