MBM_FC05_CoilWr() - Modbus-M
This function is called from YOUR application code to write to a single coil on a Modbus slave.
Prototype
CPU_INT16U MBM_FC05_CoilWr (MODBUS_CH *pch, CPU_INT08U slave_node, CPU_INT16U slave_addr, CPU_BOOLEAN coil_val);
Arguments
pch
is a pointer to the channel (returned by MB_CfgCh()
). This pointer specifies onto which channel the Modbus master will be communicating on. Of course, ‘pch
’ must have been configured as a Master when you configured the channel.
slave_node
specifies the slave ‘node address’ that you desire to change the coil value. This can be a number between 1 and 255 but needs to match the number assigned to the slave node.
slave_addr
specifies the address of the coil that you want to change. This can be from 0 to 65535.
coil_val
is the desired value of the coil and can be either: MODBUS_COIL_OFF
or MODBUS_COIL_ON
.
Returned Value
MODBUS_ERR_NONE
if the call was successful.
MODBUS_ERR_RX
if a response was not received from the slave within the timeout specified for this channel (see MB_CfgCh()
).
MODBUS_ERR_SLAVE_ADDR
If the transmitted slave address doesn't correspond to the received slave address
MODBUS_ERR_FC
If the transmitted function code doesn't correspond to the received function code
MODBUS_ERR_BYTE_COUNT
If the expected number of bytes to receive doesn't correspond to the number of bytes received.
MODBUS_ERR_COIL_ADDR
If you specified an invalid coil address.
Notes / Warnings
None
Called By
Your Modbus master application.