User's Manual

http://www.microcyber.cn
30
2 Cannot use Modbus TCP
communication
1. Check gateway
s Modbus TCP terminal port number
setting. (The default one is 502.)
2. Check if Modbus master device
s IP address is
configured correctly, and fill in gateway
s IP address
correctly, and confirm the gateway and Modbu
s
master are in the same LAN and configured in the
same network segment.
3. In Modbus Register Map
page, to check if Modbus
register map is correct.
3 Receive abnormal Modbus
response frame
1. Check if the register address (not configured
) is
read.(especiall
y when Function code 02 and Function
code 04 are used)
2.
Check if the read length is correct. (For Function code
03), the odd number of bytes should not be read.
3.
Function code 03 supports to read multiple bytes
continuously, and 2 bytes are related to 1 register
start address. The user shall pay attention to read
address and register address are related.
4.
Check if the device address and gateway address are
related. (for Modbus RTU)
5. When reading PV/TV/SV/QV, check if burst is on.
Private Protocol
1 Cannot communicate with
Private protocol
1. Check connection set of data application
s client side,
fill in gateway
s IP and port number (port number:
8880) correctly. And
confirm gateway and Modbus
master are in the same LAN and configured in the
same network segment.
2 Data received from OEM
protocol is messy code
form
1. OEM protocol output is ASCII
characters, rather than
hexadecimal data.