There are two modes of bag sealing system in our company, they are semi-automatic bag sealing system and automatic bag sealing system. The two modes of bag sealing system work instructions, one, semi-automatic sewing system, is controlled by a foot pedal, step on the foot pedal to work, and the second, automatic sewing system is using PLC to control the machine to start and stop automatically.
In order to stay afloat in today's fast-paced business environment, we make complex tasks easier to set up and manage with the help of PLCs, which are closely linked to industry uses in packaging, chemical, food and beverage processing, etc. PLC stands for "Programmable Logic Controller". Due to the increasing mechanization and automation of current packaging technology, the quantity of goods packaged has to be precise, so PLCs have been introduced to solve the problems in the field of packaging, bringing automation, saving time, raw materials and labor effort, and increasing production.
PLC system if there is a problem, the following basic troubleshooting to facilitate the enterprise to find their own:
Ⅰ. Failure phenomenon classification and preliminary diagnosis
- PLC does not respond
Phenomenon: The system can not be started, the touch screen black screen / no signal, the indicator lamps are off.
Priority troubleshooting:
⒈ Power module: Detect the input voltage (220V AC or 24V DC), whether the fuse is blown.
⒉ Power cord: Check whether the terminals are loose or oxidized (especially in humid environment).
⒊ Emergency stop button: Make sure it has not been triggered accidentally.
- Partial failure of function
Phenomenon: Interruption of bag sealing action, uncontrolled heat sealing temperature, material transfer stagnation.
Prioritization:
⒈ I/O Module: Check the status of the corresponding input/output point indicator.
⒉ Load Matching: Confirm that the load of the output point is not over the limit.
- Episodic fault
Phenomenon: Random stop, parameter jump, communication interruption.
Priority ranking:
⒈ Electromagnetic interference: Check the frequency converter, high-power devices and PLC spacing,
shielding wire grounding is reliable.
⒉ Program backup: Confirm whether the program is lost due to battery failure.
Ⅱ. Input and output module fault localization
- Fault phenomenon: sensor signal does not respond, no action of the actuator
- Possible causes:
⒈ Module damage: Relay output contact erosion, transistor breakdown or optocoupler failure.
⒉ Wiring problems: Loose terminals, signal line breakage or short circuit
⒊ Signal interference: Signal distortion due to ungrounded or neighboring strong electromagnetic equipment.
- Solution:
⒈ Replace the damaged I/O module. Relay output type can be considered to be upgraded to transistor type to improve the life time.
⒉ Re-crimp or solder loose terminals to ensure good contact.
⒊ Short-circuit unused input channels to avoid dangling and introducing interference.
Ⅲ. The program and communication failures
- Program abnormalities
Typical performance,logic confusion, dead loop, data overflow.
Solution steps:
⒈ Connect to the programming software and monitor the running status of the program online.
⒉ Check whether the counter/timer parameter is over the limit.
⒊ Restore the backup program and compare the differences.
Communication interruption:
Common causes,Baud rate setting error, terminating resistor not enabled, loose cable connector.
Solution steps:
⒈ Use RS485 tester to detect the communication signal waveform.
⒉ Verify the station number and protocol consistency between PLC and slave devices (e.g. inverter).
⒊ Replace the spare communication cable to verify if it is a cable failure.
Ⅳ. Maintenance and preventive measures
- Daily Maintenance:
Clean the PLC cooling holes and fan every month to prevent dust accumulation.
Quarterly testing of grounding resistance (≤ 4Ω) and battery voltage.
- Anti-interference design:
Power cables and signal lines are routed in separate tanks, and vertical routes are used when crossing.
Installation of isolation transformer at the input of PLC power supply.
- Emergency preparedness:
Always have spare modules (such as power supply, I/O cards).
Print and save the latest program list for quick recovery.
About PLC applications, we recommend the machine:
1. Automatic bag closing system
2. High performance bag closing system
3. Automatic bag sewing system
If interested in our PACKSTAR, please feel free to contact us.
To contact us:
WhatsApp/WeChat: 0086 13991289750/0086 13891858261
Email: sales@chinapackstar.com
