Hello.
I struggled in 'Historical H/W limit'alarm these days.Our machine is running for more than one year until now.But from last week, it always show 'Historical H/W (positive or negative)limit'alarm in both motors in turn.About one time in five or six hours.
We already changed both motors,cables,plugs power supply,and even PLC. And made a really good ground. But it always there...
We use Port 2 and Port 3 as limits through sensors, and connect them to Port 7. Pin 14,15 for 24V DC supply.Main power is 48V DC.
Could you guys give me some suggestions for this error? I really don't know why this error comes now.
Thank you very much.
It sounds like you have a noise issue "now"... because something has changed... resulting in "false" triggering of the over-travel switches. It could be noise coming from a new machine on the same AC power... hard to tell. I would recommend that you test for noise... and solve it using AC Snubbers... Flyback suppression Diodes... and better grounding.
You could possibly use "Soft Limits" after initial homing... and disable the Hardware switches after knowing the travel limits of the actuator.
Thanks very much for your reply! I will go to check the GND for the cabinet and all the cables again.If it still not works,i will check "Soft Limits"function.
I also have one more question here.
I saw when motors were running,Port 2 and 3 have no 5V voltage but Port 6 have 5V voltage.When error comes, Port 6 also have no voltage.What is the function for Port 6(G Sync)?
I read the manual of the motor,it shows i can connect Port 2,3,6 and pin 13 together.But our plugs have no pin 13 (signal GND)connection. so could i connect port 6 with Pin 14(Power GND)?
Pin13 is the common for the 5VDC logic and should be used for the I/O ports. Pin14 can have more noise due to being power ground and can cause problems.
Port 6 can be assigned as 3 things.
1. A user input/output
2. Act as if a go "G" command was issued
3. As a Sync signal for RS485 communications if the main RS232 is re-opened as an RS485 port(Class 4 motors only)
If you have the program that is in the motor... and don't mind pasting it here, I may be able to tell you something more specific. If you need to keep the code confidential... call the toll free number on the website. What is the model number of your motor? ...and firmware?
Thank you for your support.
The problem already solved.We make the reference by the block now. Canceled the limit sensor.