GW-CO-GARY Gray Code to RS485 Converter Guide

1. Function Description

This module converts gray‑code signals to RS‑485 Modbus protocol. It supports up to 15‑bit gray‑code input. Gray‑code signals from encoders, displacement sensors and other devices can be converted into standard Modbus data for communication with host computers or RTUs over the RS485 bus.

2. Technical Specifications

Basic Parameters

Item	Parameter	Remarks
Product Model	GW‑CO‑GRAY
Supply Voltage	5~28 VDC
Operating Current	＜10 mA
Ingress Protection	IP30 (Non‑waterproof; install inside control cabinet)
Operating Temperature	-40~85 ℃
Operating Humidity	0~95 % RH (non‑condensing)
Overall Dimension	82 × 66 × 18 mm
Mounting Method	DIN‑rail mounting

Measurement Parameters

Item	Parameter	Remarks
Measuring Range	Max. 15 bits

Communication Parameters

Item	Parameter	Remarks
Physical Interface	RS485	Baud rate 9600, 8N1
Communication Protocol	MODBUS	Custom non‑standard protocols supported
Physical Interface	USB‑TYPEC	USB‑TTL
Physical Interface	15‑bit gray‑code input

LED Indicators

Indicator	Description
RUN	Run indicator (flashes during normal communication)
POWER	Power indicator (steady‑on for normal power supply)

3. Terminal Definition

Top Terminals

No.	Label	Description
1	VCC	Module power supply, 5‑28 VDC
2	GND	Power ground
3	485A	RS485+
4	485B	RS485‑

Bottom Terminals

No.	Label	Description
1	DIN01	Gray‑code input Bit 1
2	DIN02	Gray‑code input Bit 2
3	DIN03	Gray‑code input Bit 3
4	DIN04	Gray‑code input Bit 4
5	DIN05	Gray‑code input Bit 5
6	DIN06	Gray‑code input Bit 6
7	DIN07	Gray‑code input Bit 7
8	DIN08	Gray‑code input Bit 8
9	DIN09	Gray‑code input Bit 9
10	DIN10	Gray‑code input Bit 10
11	DIN11	Gray‑code input Bit 11
12	DIN12	Gray‑code input Bit 12
13	DIN13	Gray‑code input Bit 13
14	DIN14	Gray‑code input Bit 14
15	DIN15	Gray‑code input Bit 15
16	COM	Common terminal

4. Power Supply

The module accepts 5‑28 VDC power input. It supports common battery sources such as 2‑6 series lithium‑ion battery packs and 1‑2 series storage batteries. The module does not enter sleep mode after power‑on. It is of low‑power design with current consumption below 10 mA under full‑speed operation. For power‑critical systems, connect VCC to a controllable power output of the main controller to reduce overall power consumption.

5. Protocol Description

Factory defaults: baud rate 9600, 8 data bits, 1 stop bit, no parity, Modbus‑RTU protocol. Custom non‑standard protocols are available for drop‑in replacement without modifying main‑controller logic.

5.1 Device Address

Default device address is 1, configurable via commands. If the address is forgotten, read data using address 0 to detect the actual device address.

When address 0 is used, ensure only one device is connected on the bus.

Parameter	Register Address	Data Type	Function Code	Description	Default Value
Converted Gray‑Code Data	0x0000	uint16 (Read‑Only)	0x03	Converted value	0
Raw Gray‑Code Data	0x0001	uint16 (Read‑Only)	0x03	Raw input value	0
Correction Factor K	0x0002	float (Read‑Write)	0x03/0x16		1
Correction Offset B	0x0004	float (Read‑Write)	0x03/0x16		0
Valid Bit Count	0x0006	uint16 (Read‑Write)	0x03/0x06	Max. 15 bits	12
Device Address	0x03E8	uint16 (Read‑Write)	0x03/0x06		1
Restore Factory Defaults	0x03E9	uint16 (Read‑Write)	0x03/0x06		0
Firmware Version	0x03A0	uint16 (Read‑Only)	0x03

5.2 Communication Examples

Example note: Read converted data (example return value 600 mm)

Read Converted Gray‑Code Data

Transmit	01 03 00 00 00 01 84 0A
Response	01 03 02 02 58 B8 DE

Modify Device Address (from 01 to 02)

Transmit	01 06 01 01 00 02 58 37
Response	01 06 01 01 00 02 58 37

6. Installation and Configuration

6.1 Hardware Connection

1. Gray‑code input: Connect encoder pins DIN01‑DIN0N sequentially to module terminals DIN01‑DIN0N (observe signal‑level matching). Connect the COM common terminal.
2. RS485 bus: Connect module 485A / 485B to bus A / B terminals. For multi‑device networks, ensure unique slave addresses.
3. Power supply: Apply DC 5‑28 V, observe correct polarity.

6.2 Software Configuration

You may view data and configure parameters with any serial‑port debugging tool using commands given in preceding chapters. Operation via visual tool Gewu Online Tool is recommended; no deep knowledge of underlying Modbus frame format is required.

1. Select official template: GW‑CO‑GRAY Gray‑Code‑to‑RS485 Module.
2. Serial‑port parameters: 9600‑8‑N‑1.
3. Click Connect Serial Port and select the serial‑port adapter connected to your computer.
4. Click Start Polling.
5. To write parameters, navigate to the corresponding register, enter the value and click Confirm Write.

7. Dimensions

Overall dimension: 82 × 66 × 18 mm

8. Precautions

Wiring Requirements

‑ Keep gray‑code signal wires and RS485 bus cables at least 30 cm away from high‑voltage power lines. ‑ Use shielded twisted‑pair cable for RS485 bus; ground the shield at one end only.

Communication Conflicts

‑ Do not assign duplicate slave addresses on one bus segment. ‑ For half‑duplex communication, the master shall wait for slave response before sending the next command.

Gray‑Code Compatibility

‑ Confirm the encoder outputs binary gray code. ‑ Leave higher‑order inputs DIN13~DIN15 unconnected if unused (e.g. for 12‑bit gray‑code devices).

Official website: www.gewuiot.com