Contents
- 1 IP address problems of HJ3200/HJ6300 series devices
- 2 Data update time problem during HJ3200/HJ6300 configuration
- 3 HJ3200/HJ6300 device name and configuration name are inconsistent, PLC alarm
- 4 HJ3200/HJ6300 Device Name Precautions
- 5 MODBUS register address problem
- 6 Check if the MODBUS channel is normal
- 7 When connecting to a slow RTU device, you need to pay attention to the sampling time
- 8 Even Byte Alignment Issues for Analog and MODBUS Registers
IP address problems of HJ3200/HJ6300 series devices
The HJ3200/HJ6300 device does not have an IP address by default. After the HJ3200/HJ6300 device is powered on, the default is to obtain an IP address automatically.
Usually there is no IP address.
If you need to configure the HJ3200/HJ6300 device, the computer needs to assign an IP address to the HJ3200/HJ6300 device first.
The method of assigning IP to HJ3200/HJ6300 device by computer is as follows:
Connect the HJ32XX device to the same local area network as the configuration computer or directly connect it to the configuration computer, from the search command of the configuration software.
In the network card selection list, select the network card in the same LAN as the HJ32XX or the network card directly connected, and click the search command.

How to assign IP address to HJ3200/HJ6300 by PLC:
The PLC will assign the IP address set during configuration to the HJ3200/HJ6300 series devices. The PLC first finds the corresponding HJ3200/HJ6300 device according to the configured device name, and then assigns the configured IP address to it.
S7-200 smart series PLC:

1200 Series PLCs:

S7-300/400 Series PLCs:

IP Address Temporary Properties of HJ32XX
The IP address assigned to the HJ32XX is temporary. After the HJ32XX device is restarted, the IP address will become invalid. Therefore, it is necessary to assign an IP address to the HJ32XX before using the HJ32XX (except for the fixed IP address configured in the MODBUS/TCP mode).
Notice:
After the HJ32XX device and PLC are configured, do not use the configuration software to search for the HJ32XX device in the mode of the specified network card, otherwise the computer will re-assign IP to the HJ32XX device, causing the communication between the PLC and the HJ32XX device to fail.
After PLC and HJ32XX device configuration, use LAN All Adapter mode to search

Data update time problem during HJ3200/HJ6300 configuration
When the HJ3200/HJ6300 device and PLC are configured, the default data update time is 2ms, that is, the HJ3200/HJ6300 device will send real-time data to the PLC according to the time of 2MS. If the PLC is configured with multiple IO devices, the PLC may be too late. These real-time data are processed, resulting in IO data loss, network reconnection, and PLC alarms.
The specific situation still needs to be determined according to the maximum cycle time of the PLC. The IO data update cycle is slightly larger than the maximum cycle cycle of the PLC. For example, the maximum cycle time of the PLC is 27mS, then the data update cycle is set to 32mS.
If the PLC network is connected to the company LAN or external network, it is recommended to set the IO data update period to 64mS or 128mS.
TIA software to check the cycle period of PLC

S7-200 smart software to view the cycle cycle of the PLC

There are many IO devices configured by the PLC, and the watchdog timeout occurs, which can be handled by configuring the update time. The recommended minimum values are as follows: the data update time of smart200 series PLC is set to 16ms or 32ms, and the gate is set to 3 times.
The data update time of S1200/S1500 series PLC is set to 8 milliseconds, and the number of watchdogs is set to 3 times.
The interface for setting data update time in TIA software

STEP7-V5.6 version software settings
double-click PROFINET bus


S7-200 smart PLC configuration

HJ3200/HJ6300 device name and configuration name are inconsistent, PLC alarm
The name of the HJ3200/HJ6300 series device is set through the “PROFINET-IO configuration software V-1.X.X” software. After setting the name of the HJ3200/HJ6300 device, the name needs to be configured on the configured node during PLC configuration, so that The configuration node of PLC corresponds to the actual HJ3200/HJ6300 device.
1200 PLC configuration:

If the two names do not correspond, the PLC will give an alarm and the configuration will fail.
SMART 200 PLC configuration:

HJ3200/HJ6300 Device Name Precautions
HJ32XX name naming rules:
- Cannot start with a number
- Special symbols such as underscore (_) cannot be included
- Commands cannot start with port
- Use lowercase as much as possible (to avoid conflicts with PLC naming rules, only STEP7 supports uppercase).
MODBUS register address problem
The register addresses of the HJ3200/HJ6300 device configuration software are all in decimal. If it is in hexadecimal, it needs to be converted into decimal.
Then input into the configuration software.

Some RTU devices add prefixes to register numbers (Siemens RTU registers are generally prefixed).
Name | index address | Corresponding to the register address filled in by HJ3200/HJ6300 |
Coil (DO) address | 00001~09999 | 0~9998(minus 00001) |
Coil (DI) address | 10001~19999 | 0~9998(minus 10001) |
Input register (AI) address | 30001~39999 | 0~9998(minus 30001) |
Input register (AO) address | 40001~49999 | 0~9998(minus 40001) |
Check if the MODBUS channel is normal
The RTU channel is configured, but it is possible that the RTU channel cannot work normally. You can check whether the RTU channel works normally by checking the debugging information.
“Show device debugging information” via the right-click menu


From the content of the data frame, it can be seen that the MODBUS address 02 read command (03) register address (00 64==100 in decimal) operation timed out.
These MODBUS channel errors will not occur if all channels are OK.
When connecting to a slow RTU device, you need to pay attention to the sampling time
Some slow RTU devices use fast query speed, which will cause RTU reading failure, especially if multiple RTUs are connected together, it may
It appears that the RTU equipment of station No. 1 can work, but the following RTUs cannot work.

Increasing the sampling interval can solve this problem.
Even Byte Alignment Issues for Analog and MODBUS Registers
Analog and MODBUS registers are generally 2 bytes or 4 bytes, and the mapping to the IW/QW space must be aligned to even bytes. For example, IW2, IW4, IW128, etc., if the data of these two bytes are aligned to odd positions, serious data read and write errors may occur.

As can be seen from the figure, the analog quantities are aligned to the even byte position