Protocol Reference

Single source of truth: protocol/fnirsi_dps150.ksy

Overview

Property	Value
ID	fnirsi_dps150
Title	FNIRSI DPS-150 Serial Protocol
KS version	0.11
Endian	le
License	MIT

Enumerations

start_byte

Value (hex)	Name
0xA1	query_or_response
0xB0	start_session_magic
0xB1	write_command
0xC1	connect_ctrl

command_id

Value (hex)	Name
0x00	connect_ctrl
0xC0	push_vin_a
0xC1	set_voltage
0xC2	set_current
0xC3	push_output
0xC4	push_vin_c
0xDB	set_output
0xDE	get_device_name
0xDF	get_fw_version
0xE0	get_hw_version
0xE1	ready_status
0xE2	push_vin_b
0xE3	push_max_current
0xFF	get_full_status

connect_state

Value (hex)	Name
0x00	disconnect
0x01	connect

output_state

Value (hex)	Name
0x00	disabled
0x01	enabled

Command Catalogue

Hex	Name	Payload type	Description
0x00	connect_ctrl	connect_payload	Payload for CMD connect_ctrl (0x00). DATA = 0x01 → [...]
0xC0	push_vin_a	float32_payload	Single IEEE 754 32-bit LE float (voltage in V or [...]
0xC1	set_voltage	float32_payload	Single IEEE 754 32-bit LE float (voltage in V or [...]
0xC2	set_current	float32_payload	Single IEEE 754 32-bit LE float (voltage in V or [...]
0xC3	push_output	push_output_payload	CMD 0xc3 – periodic output measurement push (LEN=12, [...]
0xC4	push_vin_c	float32_payload	Single IEEE 754 32-bit LE float (voltage in V or [...]
0xDB	set_output	output_enable_payload	Payload for CMD set_output (0xdb). DATA = 0x01 → [...]
0xDE	get_device_name	string_payload	Variable-length ASCII string (no NUL terminator).
0xDF	get_fw_version	string_payload	Variable-length ASCII string (no NUL terminator).
0xE0	get_hw_version	string_payload	Variable-length ASCII string (no NUL terminator).
0xE1	ready_status	ready_payload	Device ready status (CMD 0xe1).
0xE2	push_vin_b	float32_payload	Single IEEE 754 32-bit LE float (voltage in V or [...]
0xE3	push_max_current	float32_payload	Single IEEE 754 32-bit LE float (voltage in V or [...]
0xFF	get_full_status	full_status_payload	CMD 0xff – full status blob (LEN=0x8b = 139 bytes). [...]

Payload Types

output_enable_payload

Payload for CMD set_output (0xdb).

Field	Type	Description
state	u8 (enum: output_state)

connect_payload

Payload for CMD connect_ctrl (0x00).

Field	Type	Description
state	u8 (enum: connect_state)

ready_payload

Device ready status (CMD 0xe1).

Field	Type	Description
ready	u8	0x01 = device ready, 0x00 = not ready.

string_payload

Variable-length ASCII string (no NUL terminator).

Field	Type	Description
value	bytes (rest)

float32_payload

Single IEEE 754 32-bit LE float (voltage in V or current in A).

Field	Type	Description
value	f32 LE

push_output_payload

CMD 0xc3 – periodic output measurement push (LEN=12, three floats).

Field	Type	Description
vout	f32 LE	Measured output voltage [V].
iout	f32 LE	Measured output current [A].
pout	f32 LE	Measured output power [W]. Confirmed from capture row 12827: Vout≈8.45 V, Iout≈0.0077 A → Pout≈0.065 W.

full_status_payload

CMD 0xff – full status blob (LEN=0x8b = 139 bytes).

Field	Type	Description
vin	f32 LE	Measured input voltage [V].
vset	f32 LE	Current voltage set-point [V].
iset	f32 LE	Current current limit [A].
vout	f32 LE	Measured output voltage [V] (0 when output off).
iout	f32 LE	Measured output current [A] (0 when output off).
pout	f32 LE	Measured output power [W] (0 when output off).
vin2	f32 LE	Secondary input voltage measurement [V] – TBD.
vset2	f32 LE	Duplicate / channel-2 Vset – TBD.
iset2	f32 LE	Duplicate / channel-2 Iset – TBD.
presets	preset ×5	Five stored presets (Vset, Iset each).
max_voltage	f32 LE	Device maximum output voltage [V] (30.0).
max_current	f32 LE	Device maximum output current [A] (5.1).
max_power	f32 LE	Device maximum output power [W] (150.0 = DPS-150).
max_temp	f32 LE	Maximum temperature [°C]? (80.0 – TBD).
unknown_f	f32 LE	Unknown float at offset 92 – TBD.
remainder	bytes (rest)	Mixed-type tail (offsets 96–138). Layout TBD.

preset

One stored preset (Vset + Iset pair).

Field	Type	Description
vset	f32 LE	Preset voltage set-point [V].
iset	f32 LE	Preset current limit [A].

Checksum

Every frame ends with a 1-byte checksum:

CHKSUM = (CMD + LEN + Σ DATA bytes) mod 256

The DIR and START bytes are excluded from the checksum calculation. Confirmed by byte-exact comparison against captured frames.