Pymate-Modbus-basic - Revision history

Dodomi: /* Example 3: Light/Humidity/Temperature sensor */

2026-07-05T19:17:29Z

Example 3: Light/Humidity/Temperature sensor

← Older revision		Revision as of 21:17, 5 July 2026
Line 216:		Line 216:
	The module slave address and baudrate can be changed with special RS485 calls.		The module slave address and baudrate can be changed with special RS485 calls.

	[[File:Pymate-Modbus-basic-30.~~png~~\|800px]]		[[File:Pymate-Modbus-basic-30.jpg\|800px]]

	=== Code ===		=== Code ===

2026-07-05T18:39:36Z

Code

@@ Line 220: / Line 220: @@
 === Code ===
 <syntaxhighlight lang="python" line start="1">
 </syntaxhighlight>

2026-07-05T18:19:06Z

Example 2: Power Meter

@@ Line 202: / Line 202: @@
 print( 'Maximum Voltage     :', meter.max_voltage, 'Volts' )
 print( 'Maximum Current     :', meter.max_current, 'Amps' )
 </syntaxhighlight>

2026-07-05T18:12:18Z

Practical example 2

← Older revision		Revision as of 20:12, 5 July 2026
Line 68:		Line 68:
	</syntaxhighlight>		</syntaxhighlight>

	== ~~Practical example~~ 2 ==		== Example 2: Power Meter ==
	The following example shows how to grab the data from a Modbus Single-Phase Power-Meter device from Etek.		The following example shows how to grab the data from a Modbus Single-Phase Power-Meter device from Etek.

2026-07-05T18:11:53Z

Practical example 1

← Older revision		Revision as of 20:11, 5 July 2026
Line 10:		Line 10:
	{{dbox-orange\| RS485 output can be use either for '''Modbus over RS485''', either for '''Direct RS485'''. Both access methods cannot be used together on the RS485 output. }}		{{dbox-orange\| RS485 output can be use either for '''Modbus over RS485''', either for '''Direct RS485'''. Both access methods cannot be used together on the RS485 output. }}

	== ~~Practical example~~ 1 ==		== Example 1: Wind Direction ==
	The following example shows how to grab the data from a RS485 Wind Direction device. The Wind Direction is a Modbus device.		The following example shows how to grab the data from a RS485 Wind Direction device. The Wind Direction is a Modbus device.

2026-05-29T13:36:00Z

Unable to communicate over ModBus

← Older revision		Revision as of 15:36, 29 May 2026
Line 257:		Line 257:
	Sometime, it is necessary to give a little push to the RS485 bus to improve the signal quality.		Sometime, it is necessary to give a little push to the RS485 bus to improve the signal quality.

	When the 120 Ω terminator resistor is not enough to a communication, you can add a 1 KΩ Pull-Up Resistor from A+ to 5V as well as a 1 KΩ pull-Down resistor.		When the 120 Ω terminator resistor is not enough to a communication, you can add a 1 KΩ Pull-Up Resistor from A+ to 5V as well as a 1 KΩ pull-Down resistor to GND.

	Here an example based on Power-Meter.		Here an example based on Power-Meter.

2026-05-29T13:35:30Z

Modbus Cheat Sheet

2026-05-29T13:34:59Z

Modbus Cheat Sheet

← Older revision		Revision as of 15:34, 29 May 2026
Line 214:		Line 214:
	brd = Board()		brd = Board()
	modbus = brd.modbus(baudrate=9600)</nowiki>		modbus = brd.modbus(baudrate=9600)</nowiki>

			Reading the holding register is made as follow:

			<nowiki>reg_value = modbus.read_holding_registers( slave_addr=0x02, starting_addr=0x0000, register_qty=1, signed=False)
			# Returns tuple of uint16. Ex: (2427,)
			# Grabbing the value is made as the following
			value = reg_value[0] </nowiki>

	Supported Modbus functions		Supported Modbus functions
Line 245:		Line 252:
	* READ_WRITE_MULTIPLE_REGISTERS = 23		* READ_WRITE_MULTIPLE_REGISTERS = 23
	* DEVICE_INFO = 43		* DEVICE_INFO = 43

	~~<nowiki>reg_value = modbus.read_holding_registers( slave_addr=0x02, starting_addr=0x0000, register_qty=1, signed=False)~~
	~~# Returns tuple of uint16. Ex: (2427,)~~
	~~# Grabbing the value is made as the following~~
	~~value = reg_value[0] </nowiki>~~

	== Modbus error ==		== Modbus error ==

2026-05-29T11:14:47Z

Modbus Cheat Sheet

← Older revision		Revision as of 13:14, 29 May 2026
Line 205:		Line 205:

	== Modbus Cheat Sheet ==		== Modbus Cheat Sheet ==
			As a programmer, there is a chance for you to develop your own code to access a Modbus device. We can also provide support for this.

	~~Create an~~ {{fname\|~~modbus~~}} instance object.		In such case, you will have to rely on the {{fname\|umodbus}} library (see [https://github.com/brainelectronics/micropython-modbus umodbus project], [https://micropython-modbus.readthedocs.io/en/latest/ umodbus documentation]).

			Create an '''modbus''' instance object.

	<nowiki>from pymate.board import Board		<nowiki>from pymate.board import Board

2026-05-29T11:07:58Z

Practical example 2

← Older revision		Revision as of 13:07, 29 May 2026
Line 79:		Line 79:
	The module slave address can be displayed and changed from the module LCD.		The module slave address can be displayed and changed from the module LCD.

	[[File:Pymate-Modbus-basic-20.png]]		[[File:Pymate-Modbus-basic-20.png\|800px]]

	=== Code : Single-Phase ===		=== Code : Single-Phase ===