Q. The created program does not work.
A. First of all, please use the enclosed sample to check the following simple operation.
If it still does not work, please contact CONTEC Technical Support Center with the confirmation result.
Q1 : Is there a Modbus communication sample collection in the start menu ?
A : If it does not exist, please reinstall it.
Q2 : Is the slave device turned on ?
A : If the power is off, turn it on.
If the device does not boot when you turn it on, please contact the device manufacturer.
Q3 : Are the host PC and slave device connected with a LAN cable or serial cable ?
A : If they are not connected, please connect them with the cable.
For serial cables, please also check the pin assignments.
Q4 : Is the slave device a Modbus TCP or Modbus RTU compatible product ?
A : Since this sample uses Modbus communication, it can only be used with Modbus compatible products.
Q5 : Does the corresponding FunctionCode of the slave device match the FunctionCode used in the sample ?
A : If they do not match, please use the FunctionCode corresponding to the slave device.
Q6 : Is the address you are reading or writing within the address range of the slave device ?
A : If it is not within the address range, please use within the address range allowed by the slave device.
Q1 : Does Ping pass ?
A : If Ping does not pass, please check the IP address and subnet mask.
Please refer to the following for how to execute Ping.
◆ How to execute Ping
- Open the command prompt, and execute "Ping XXX.XXX.XXX.XXX".
* Specify the IP address of the slave device in "XXX".
Q2 : Does the port used match the slave device ?
A : If it does not match, please use it according to the port of the slave device.
Q1 : Do the various serial settings (COM number, baudrate, parity, etc.) match the slave device ?
A : If they do not match, please match the settings of the slave device.
Please also check if it can be used with products that use various serial settings.
Q2 : Does the slave ID match?
A : If it does not match, please match the settings of the slave device.
Q3 : If the Tx/Rx part has an LED, please check whether it lights up when sending or receiving commands.
A : If the Tx of the COM port on the master PC does not light up, there is a possibility that sending data has not been performed.
Do the used COM ports match ? Please check the function that sends data is successful.
If the Tx of the COM port on the master PC lights up and the Rx on the slave device does not light up,
there is a possibility that the wire is broken or the pin assignment is different, so please check the cable you are using as well.