Y301-220/222 Technical Manual

Y301-220	Y301-222

• Specification

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Contents

1. Overview
2. Default Settings
3. Modbus Register Map (Modbus Address Only)
4. Command Examples (CRC Included)
5. Parameter Configuration
6. Automation Rules
7. Troubleshooting

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1. Overview

This manual describes the Modbus RTU communication commands for the Y301-220 and Y301-222 I/O modules.

Model	DI	DO	AI	Description
Y301-220	2	2	0	Dual input + dual relay
Y301-222	2	2	2	Dual input + dual relay + dual analog input

Frame format: [slave address][function code][data][CRC low][CRC high]

The examples below use slave address 0x01. Replace it with the actual device address in your application.

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2. Default Settings

Parameter	Default
Slave address	1
Baud rate	9600 bps
Data bits	8
Stop bits	1
Parity	None
Output state hold	Keep after soft reboot (0x0040 = 1)
Pulse counting edge	Rising edge (0x0041 = 1)
Pulse debounce	50 ms (0x0042 = 50)

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3. Modbus Register Map (Modbus Address Only)

3.1 Digital Input (DI) - Function Code 0x02

Channel	Modbus Address	R/W
DI1	0x0000	RO
DI2	0x0001	RO

Return value: 0 = inactive, 1 = active.

3.2 Digital Output (DO) - Function Code 0x01/0x05/0x0F

Channel	Modbus Address	R/W
DO1	0x0000	RW
DO2	0x0001	RW

Write value: 0x0000 = open, 0xFF00 = closed.

3.3 Analog Input (AI) - Function Code 0x04 (Y301-222 only)

Channel	Modbus Address	Description	Unit	R/W
AI1 voltage	0x0000	AI1 sampled voltage	mV	RO
AI1 current	0x0001	AI1 sampled current	uA	RO
AI2 voltage	0x0002	AI2 sampled voltage	mV	RO
AI2 current	0x0003	AI2 sampled current	uA	RO

Each AI channel can be wired for either voltage or current. The other reading is invalid.

3.4 Common Holding Registers (Parameters) - Function Code 0x03/0x06/0x10

Modbus Address	Parameter	Bytes	R/W	Range / Enum	Default
0x002A	Runtime slave address (device addr + DIP offset)	2	RO	0-255	-
0x002B	DIP offset address	2	RO	0-31	0
0x003E	Slave address	2	RW	1-255	1
0x003F	Broadcast mode	2	RW	0=off, 1=recv+reply, 2=recv no reply	0
0x0040	Output state hold	2	RW	0=no hold, 1=soft reboot hold, 2=soft reboot + power-on hold	1
0x0041	Pulse count edge	2	RW	0=falling, 1=rising	1
0x0042	Pulse debounce (ms)	2	RW	5-255	50
0x004C	Serial heartbeat period (s)	2	RW	0=off, 1-65535	0
0x004D	Serial heartbeat payload	16	RW	string	-
0x0055	RTC Unix time	4	RW	uint32	-
0x0057	Baud rate	4	RW	600-230400	9600
0x0059	Data bits	2	RW	8, 9	8
0x005A	Stop bits	2	RW	1, 2	1
0x005B	Parity	2	RW	0=None, 1=Odd, 2=Even	0
0x005C	Packet timeout (ms)	2	RW	0-255 (0=adaptive)	0

Notes:

• 32-bit values (for example 0x0055, 0x0057) should be written in big-endian word order (high word first).
• Per manufacturer behavior, changing serial parameters or slave address requires reboot to take effect.

3.5 DI Pulse Counter Registers (Holding Registers)

Channel	Modbus Address	Bytes	R/W	Description
DI1 count	0x0500 (uses 0x0500~0x0501)	4	RW	Only 0 is allowed for write (clear)
DI2 count	0x0502 (uses 0x0502~0x0503)	4	RW	Only 0 is allowed for write (clear)

3.6 Automation Rule Registers (Holding Registers)

Y301-220/222 has 2 DO channels, so total rule groups = DO * 2 = 4.

Rule Group	Start Modbus Address	Length
Rule 1	0x0080	8 registers (16 bytes)
Rule 2	0x0088	8 registers (16 bytes)
Rule 3	0x0090	8 registers (16 bytes)
Rule 4	0x0098	8 registers (16 bytes)

Single-group field structure:

Offset	Field	Bytes
+0	Mode	2
+1	Action	2
+2	DO index	2
+3	DI/AI index	2
+4~+5	Parameter 1	4
+6~+7	Parameter 2	4

3.7 Special Register

Modbus Address	Name	Write Value	Description
0x0800	Reboot / Factory reset	0x5500=reboot, 0x0055 or 0x5555=factory reset + reboot	WO

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4. Command Examples (CRC Included)

Tip: each command is shown in an individual code block. VitePress displays a copy icon on the top-right of every code block, so users can click once to copy the Modbus command.

4.1 Read Digital Inputs

Operation	Request
Read DI1	01 02 00 00 00 01 B9 CA
Read DI2	01 02 00 01 00 01 E8 0A
Read DI1~DI2 in one shot	01 02 00 00 00 02 F9 CB

4.2 Read Digital Output Status

Query (0x01):

Operation	Request
Read DO1	01 01 00 00 00 01 FD CA
Read DO2	01 01 00 01 00 01 AC 0A
Read DO1~DO2 in one shot	01 01 00 00 00 02 BD CB

Single-channel control (0x05):

Operation	Request
Open DO1	01 05 00 00 00 00 CD CA
Close DO1	01 05 00 00 FF 00 8C 3A
Open DO2	01 05 00 01 00 00 9C 0A
Close DO2	01 05 00 01 FF 00 DD FA

Multi-channel control (0x0F):

Operation	Request
Close DO1 and DO2 together	01 0F 00 00 00 02 01 03 9E 96
Open DO1 and DO2 together	01 0F 00 00 00 02 01 00 DE 97

4.3 Read Analog Inputs (Y301-222 only)

Operation	Request
Read AI1 voltage	01 04 00 00 00 01 31 CA
Read AI1 current	01 04 00 01 00 01 60 0A
Read AI2 voltage	01 04 00 02 00 01 90 0A
Read AI2 current	01 04 00 03 00 01 C1 CA
Read AI1+AI2 (voltage+current, 4 regs)	01 04 00 00 00 04 F1 C9

4.4 Parameter Read/Write (0x03/0x06/0x10)

Device address:

Operation	Request
Read slave address (0x003E)	01 03 00 3E 00 01 E5 C6
Write slave address = 5	01 06 00 3E 00 05 28 05

Serial parameters:

Operation	Request
Read baud rate (0x0057, 2 regs)	01 03 00 57 00 02 75 DB
Write baud rate = 115200 (0x0001C200)	01 10 00 57 00 02 04 00 01 C2 00 B7 D5
Write baud rate = 9600 (0x00002580)	01 10 00 57 00 02 04 00 00 25 80 AC 45
Read data/stop/parity (0x0059~0x005B)	01 03 00 59 00 03 D5 D8
Write 8N1	01 10 00 59 00 03 06 00 08 00 01 00 00 85 EF

State hold and count settings:

Operation	Request
Read output state hold (0x0040)	01 03 00 40 00 01 85 DE
Write output state hold = 2	01 06 00 40 00 02 09 DF
Read pulse edge (0x0041)	01 03 00 41 00 01 D4 1E
Write pulse edge = 1 (rising)	01 06 00 41 00 01 18 1E
Read debounce (0x0042)	01 03 00 42 00 01 24 1E
Write debounce = 50 ms	01 06 00 42 00 32 A8 0B

4.5 DI Pulse Counter Read/Write

Operation	Request
Read DI1 count (0x0500, 2 regs)	01 03 05 00 00 02 C4 C7
Read DI2 count (0x0502, 2 regs)	01 03 05 02 00 02 65 07
Clear DI1 count (write 0)	01 10 05 00 00 02 04 00 00 00 00 CC FF

4.6 Special Operations

Operation	Request
Reboot (0x0800=0x5500)	01 06 08 00 55 00 B4 FA
Factory reset + reboot (0x0800=0x0055)	01 06 08 00 00 55 4B 95

4.7 Copy-Ready Command Blocks

Commonly used commands are listed below as plain command blocks for one-click copy:

01 02 00 00 00 02 F9 CB

01 0F 00 00 00 02 01 03 9E 96

01 04 00 00 00 04 F1 C9

01 10 00 57 00 02 04 00 01 C2 00 B7 D5

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5. Parameter Configuration

5.1 Runtime Slave Address

Runtime slave address = configured device address (0x003E) + DIP offset (0x002B).

For hardware versions without DIP offset support, 0x002B is usually 0, so runtime address equals device address.

5.2 Serial Settings

• Baud rate is stored at 0x0057 as a 32-bit value, so use 0x10 to write 2 registers.
• Data bit / stop bit / parity are located at 0x0059~0x005B.
• Per manufacturer behavior, serial parameters and slave address require reboot to take effect.

5.3 Broadcast Mode (0x003F)

Value	Meaning
0	Broadcast processing off
1	Receive and reply to broadcast
2	Receive but do not reply

5.4 Output State Hold (0x0040)

Value	Meaning
0	No hold
1	Hold after soft reboot
2	Hold after soft reboot and power-on reboot

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6. Automation Rules

6.1 Supported Modes

Mode	Name	Description
0	Disabled	Rule is disabled
1	DI follow	DO follows DI (normal/inverse by action)
2	Pulse output	DO returns after delay
3	Delayed control	Open/close/all actions delayed
4	Timed change	Execute once after delay from reboot
5	Cyclic change	Toggle by parameter1/parameter2 cycle
6	Button (jog)	DI works as a button to trigger DO
7	Fixed-point one-shot	Execute once at target Unix time
8	Fixed-point cyclic	Repeat by interval from target time
9	Daily schedule	Execute every day at target second-of-day
10	AI voltage > threshold	Y301-222 only
11	AI voltage < threshold	Y301-222 only
12	AI current > threshold	Y301-222 only
13	AI current < threshold	Y301-222 only
14	Delayed follow	Follow DI after delay
15	Logical AND	Multi-channel DI/DO AND logic
16	Logical OR	Multi-channel DI/DO OR logic
17	Logical XOR	Multi-channel DI/DO XOR logic

6.2 Rule Command Examples

All examples below write to Rule 1 (start 0x0080) with slave address 0x01.
For Rule 2/3/4, replace start address with 0x0088 / 0x0090 / 0x0098 and recalculate CRC.

Action code reference: 0=open, 1=close, 2=toggle (depends on mode).

• Case 1: DI Follow (Mode 1): DO1 follows DI1

Field	Value	Description
Mode	0x0001	DI follow
Action	0x0001	Forward follow (close when DI=1)
DO index	0x0001	DO1
DI/AI index	0x0001	DI1
Parameter 1	0x00000000	Not used
Parameter 2	0x00000000	Not used

01 10 00 80 00 08 10 00 01 00 01 00 01 00 01 00 00 00 00 00 00 00 00 CC FE

• Case 2: AI Voltage > Threshold (Mode 10): if AI1 > 5V, open DO1

Field	Value	Description
Mode	0x000A	AI voltage greater than threshold
Action	0x0000	Open
DO index	0x0001	DO1
DI/AI index	0x0001	AI1
Parameter 1	0x00001388	Threshold 5000 mV (= 5 V)
Parameter 2	0x000003E8	Execution interval 1000 ms (debounce)

01 10 00 80 00 08 10 00 0A 00 00 00 01 00 01 00 00 13 88 00 00 03 E8 67 7A

• Case 3: AI Voltage < Threshold (Mode 11): if AI1 < 2V, close DO1

Field	Value	Description
Mode	0x000B	AI voltage lower than threshold
Action	0x0001	Close
DO index	0x0001	DO1
DI/AI index	0x0001	AI1
Parameter 1	0x000007D0	Threshold 2000 mV (= 2 V)
Parameter 2	0x000003E8	Execution interval 1000 ms

01 10 00 80 00 08 10 00 0B 00 01 00 01 00 01 00 00 07 D0 00 00 03 E8 86 22

Detailed breakdown for this case (later examples follow the same pattern):

Byte Sequence	Meaning
01	Slave address = 0x01
10	Function code = 0x10 (Write Multiple Holding Registers)
00 80	Start register = 0x0080 (Rule 1 base address)
00 08	Register count = 8 (16-byte rule payload)
10	Byte count = 16
00 0B	Mode = 0x000B (AI voltage lower than threshold)
00 01	Action = 0x0001 (close)
00 01	DO index = 1 (DO1)
00 01	DI/AI index = 1 (AI1)
00 00 07 D0	Parameter 1 = 2000 mV = 2.0V threshold
00 00 03 E8	Parameter 2 = 1000 ms trigger interval / debounce
86 22	CRC16 (low byte first)

Meaning summary: this writes a rule to Rule 1 so that when AI1 voltage is lower than 2V, DO1 closes, with a minimum execution interval of 1000 ms.

• Case 4: AI Current > Threshold (Mode 12): if AI1 > 10mA, close DO1

Field	Value	Description
Mode	0x000C	AI current greater than threshold
Action	0x0001	Close (turn on)
DO index	0x0001	DO1
DI/AI index	0x0001	AI1
Parameter 1	0x00002710	Threshold 10000 uA (= 10 mA)
Parameter 2	0x000003E8	Execution interval 1000 ms (debounce)

01 10 00 80 00 08 10 00 0C 00 01 00 01 00 01 00 00 27 10 00 00 03 E8 C6 51

• Case 5: AI Current < Threshold (Mode 13): if AI1 < 4mA, open DO1

Field	Value	Description
Mode	0x000D	AI current lower than threshold
Action	0x0000	Open
DO index	0x0001	DO1
DI/AI index	0x0001	AI1
Parameter 1	0x00000FA0	Threshold 4000 uA (= 4 mA)
Parameter 2	0x000003E8	Execution interval 1000 ms

01 10 00 80 00 08 10 00 0D 00 00 00 01 00 01 00 00 0F A0 00 00 03 E8 42 22

• Case 6: Pulse Output (Mode 2): DO1 normally open, auto-recover after 2s close

Field	Value	Description
Mode	0x0002	Pulse output
Action	0x0000	Normally open
DO index	0x0001	DO1
DI/AI index	0x0000	Not used
Parameter 1	0x000007D0	Pulse duration 2000 ms
Parameter 2	0x00000000	Not used

01 10 00 80 00 08 10 00 02 00 00 00 01 00 00 00 00 07 D0 00 00 00 00 40 8B

• Case 7: Delayed Control (Mode 3): DO1 open command delayed by 3s

Field	Value	Description
Mode	0x0003	Delayed control
Action	0x0000	Delayed open only
DO index	0x0001	DO1
DI/AI index	0x0000	Not used
Parameter 1	0x00000BB8	Delay 3000 ms
Parameter 2	0x00000000	Not used

01 10 00 80 00 08 10 00 03 00 00 00 01 00 00 00 00 0B B8 00 00 00 00 E0 8E

• Case 8: Cyclic Change (Mode 5): DO1 open 1s, close 2s in cycle

Field	Value	Description
Mode	0x0005	Cyclic change
Action	0x0000	Open first
DO index	0x0001	DO1
DI/AI index	0x0000	Not used
Parameter 1	0x000003E8	Open duration 1000 ms
Parameter 2	0x000007D0	Close duration 2000 ms

01 10 00 80 00 08 10 00 05 00 00 00 01 00 00 00 00 03 E8 00 00 07 D0 A4 64

• Case 9: Button/Jog (Mode 6): DI1 button toggles DO1

Field	Value	Description
Mode	0x0006	Button (jog)
Action	0x0002	Toggle
DO index	0x0001	DO1
DI/AI index	0x0001	DI1 as button input
Parameter 1	0x000003E8	Press duration 1000 ms
Parameter 2	0x00000000	Not used

01 10 00 80 00 08 10 00 06 00 02 00 01 00 01 00 00 03 E8 00 00 00 00 EE 1B

• Case 10: Logical AND (Mode 15): DO1 close only when DO2=close and DI1+DI2=active

Field	Value	Description
Mode	0x000F	Logical AND
Action	0x0004	Close (hold)
DO index	0x0001	DO1
DI/AI index	0x0000	Not used
Parameter 1	0x00000002	DO2 participates in logic (bit1=1)
Parameter 2	0x00000003	DI1+DI2 participate in logic (bit0+bit1=1)

01 10 00 80 00 08 10 00 0F 00 04 00 01 00 00 00 00 00 02 00 00 00 03 7A AE

• Case 11: Timed Change (Mode 4): after reboot, close DO1 in 5s

Field	Value	Description
Mode	0x0004	Timed change
Action	0x0001	Close
DO index	0x0001	DO1
DI/AI index	0x0000	Not used
Parameter 1	0x00001388	Timer 5000 ms
Parameter 2	0x00000000	Not used

01 10 00 80 00 08 10 00 04 00 01 00 01 00 00 00 00 13 88 00 00 00 00 E6 D1

• Case 12: Daily Schedule (Mode 9): open DO1 every day at 18:00:00

Field	Value	Description
Mode	0x0009	Daily schedule
Action	0x0000	Open
DO index	0x0001	DO1
DI/AI index	0x0000	Not used
Parameter 1	0x0000FD20	Seconds of day 64800 (18x3600)
Parameter 2	0x00000000	Not used

01 10 00 80 00 08 10 00 09 00 00 00 01 00 00 00 00 FD 20 00 00 00 00 5F C3

Note: modes 7~9 depend on RTC time. After reboot, write current Unix timestamp to RTC register 0x0055 first.

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7. Troubleshooting

Symptom	Cause	Solution
No response	Wrong address or baud rate	Check settings and try broadcast address 0
CRC error	Wiring issue or interference	Check RS485 polarity and add termination resistors
DO does not switch	Load exceeds rating	Reduce the load and verify contact ratings
DI always reads 0	Wiring error	Check COM/DI wiring and input voltage
AI reading is abnormal	Wrong wiring mode	Verify voltage/current wiring; each channel supports only one mode at a time

LED Indicators

LED	Status	Meaning
POWER	Solid on	Power is normal
TX	Flashing	Data is being transmitted
RX	Flashing	Data is being received
DI1/DI2	On	Input is active
DO1/DO2	On	Relay is closed

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• Manufacturer: Hunan YenGear Tech Co., Ltd.
• Email: [email protected]
• Website: www.yengear.com