S7 Monitoring the battery

D

Thread Starter

David Cole

I'm trying to research whether there is any means within the S7 315DP PLC program to monitor for a dead battery. I know a LED will turn on, but I would like to send a message out to a HMI.


David Cole
[email protected]
---------------------------------
 
Give this a whirl
Copy this in to OB81- Your hardware Fault OB.
This logic will convert to LAD.



Copy in to Network 1

A(
L #OB81_FLT_ID
T #OB81_FLT_ID_INT
SET
SAVE
CLR
A BR
)
JNB _001
L #OB81_EV_CLASS
T #OB81_EV_CLASS_INT
_001: NOP 0


Copy to network 2

A(
L #OB81_FLT_ID_INT
L 34
==I
)
A(
L #OB81_EV_CLASS_INT
L 57
==I
)
S "Your HMI Low Battery Bit"


Copy to network 3- This resets alarm bit when battery is replaced


A(
L #OB81_FLT_ID_INT
L 34
==I
)
A(
L #OB81_EV_CLASS_INT
L 56
==I
)
R "Your HMI Low Battery Bit"
 
G

Gabriele Corrieri

About this code: is valid for all 300-type CPU's or runs only onto 315DP2? I'm interested also an possible pre-alarm, because our machines are started at morning and stopped at evening, if battery is discharged by night or week-end all parameter stored in memory go out, and in some case (without MC) the entire logic ladder is lost. Pre Alarm features give an message to HMI for changing battery at safe time. Thanks in advance

Gabriele Corrieri
 
Gabriele,

This code will work for all 300/400 CPU's. If you recieve this alarm on your HMI and you dont wait too long, it will probably have enough
charge to hold the memory (again- for a short time) Of course if the battery is completely dead- your program is gone. You might want to
consider buying an EEPROM. The above code will keep the alarm "on" until the battery is replaced.
 
Dear Mr/Ms
I have a strange problem with our Automation system that include S7400 PLC, last week it had an error which indicates that power supply battery is to low on HMI and Power Supply and I changed it 2 times as soon as possible but during recent week, unfortunately, every time that machine turning on again this alarm appear just on HMI but also there is no fault on PLC rack.
Could you please tell me how to solve this problem?
 
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