AC500 Battery¶
The AC500 battery buffers the following data in case of “control voltage off”:
- Retentive variables in SRAM (VAR_RETAIN..END_VAR) Inputs, Outputs and Flags for AC500 V2 Products
- Persistent data in %R area
- Date and time of the real-time clock
Note
- For AC500-eCo Processor Modules the battery is not required for retentive/persistent variables. These variables are stored in the Flash memory when the Processor Module is shutting down.
- For AC500 (Standard) Processor Module PM595-4ETH-M, no battery is needed to buffer retentive/persistent variables as the MRAM will keep its content during power-off. Only the real-time clock is buffered by the battery.
- Parameter configuration on the Processor Module: Parameters of the Processor Module
- PLC diagnosis: Error Lists
Note
To prevent data loss when using the AC500 battery, the battery status should be periodically monitored by the user or by the user program.
If no battery is inserted or if the battery is empty, a warning (E4) is generated and the LED “ERR” lights up.
If no battery is required for the application (and thus no battery is inserted), a warning is generated and the error LED lights up each time the controller is switched on. To avoid this battery error indication, the parameter “Check Battery” is available under “CPU parameters” in the PLC configuration. The default setting of this parameter is “On”, i.e., battery check is performed. If this parameter is set to “Off”, the battery check is still performed and a corresponding error message is still generated each time the control voltage is switched on, but the system automatically quits this error and therefore the error LED does not light up (provided no further error exists).
Battery status
The battery status can be monitored either with the help of a user program on the PLC or in Automation_Builder.
In the PLC browser of Automation_Builder the command “batt” can be used (see PLC browser): AC500-Specific PLC Browser Commands
| 0 | Battery empty |
| 20 | Remaining battery charge below 20 % |
| 100 | Battery charge OK |
In the user program, the battery status can be checked with the function BATT: BATTSysExt_AC500_Vxx.lib. The following is output:
| 0 | Battery empty |
| 20 | Remaining battery charge below 20 %, battery must be replaced |
| 100 | Battery charge OK |
On the device, the battery status can be checked with the function keys of a Processor Module. LEDs, Display and Function Keys on the Front Panel
Reading out Values: Reading out Values