embedded systems modbus - read coil status - function code 01

up: embedded systems - modbus - commands

Request

Field	size	range of values
slave address	8 bits	0-255
function code	8 bits	01
First Coil to be Read	16 bits
Number of Coils to be Read	16 bits
Error check	16 bits	CRC

Response

Field	size	range of values
function code	8 bits	01
Number of bytes to follow	8 bits
Coil Data	variable	8 coils per byte
Error check	16 bits	CRC

Notes:

In the response, the LSB of the response bytes contains the lower coil address, the MSB contains the higher.
If the number of coils requested is not an even multiple of 8, the last byte is filled with zero bits

Resources
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filename:	embedded systems modbus - read coil status - function code 01
filename:	embedded%20systems%20modbus%20%2D%20read%20coil%20status%20%2D%20function%20code%2001
last edit:	August 31 2014 21:09:44 (-4717696 minutes ago)
ct	= 1126471989.000000 = September 11 2005 16:53:09
ft	= 1409533784.000000 = August 31 2014 21:09:44
dt	= -283061795.000000