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Entry type: FAQ Entry ID: 109762978, Entry date: 01/23/2019
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Why do you get the message "Buffering mode not possible due to low charge" even though the buffer module is fully charged and ready for buffering?

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  • Associated product(s)
If you are using the SITOP PSU8600 V1.4 together with a SITOP BUF8600 4s/40A V1.4 or SITOP BUF8600 10s/40A V1.4, these modules should not be operated in Compatibility mode if the configuration is less than V1.4.

In STEP 7 (TIA Portal) you configure the PSU8600 and the BUF8600 4s/40A or BUF8600 10s/40A with firmware V1.4 that is also actually loaded on the device.

When operating in Compatibility mode the following message remains displayed after switching on the power, even though the buffer module is fully charged and ready for buffering, if the buffer module had been buffered empty before switch-off.

  • Buffering mode not possible due to low charge


Fig. 1

   
S7-CPU diagnostics buffer
The following messages are displayed in the diagnostics buffer of the S7-CPU:
  • Diagnostics available and is being processed
  • Error in the buffer expansion module


Fig. 2

S7-CPU diagnostics status
Fig. 2 shows the diagnostics status in the S7-CPU.


Fig. 3

PSU8600 diagnostics status
Fig. 3 shows the diagnostics status in the PSU8600.


Fig. 4

Remedy
In STEP 7 (TIA Portal) you configure the PSU8600 and the BUF8600 4s/40A or BUF8600 10s/40A with firmware V1.4 that is also actually loaded on the device. If you have been operating the SITOP PSU8600 V1.4 together with a SITOP BUF8600 4s/40A V1.4 or SITOP BUF8600 10s/40A V1.4 in Compatibility mode with a configuration less than V1.4, proceed as follows:

  1. In the Devices and Networks editor you open the Device View of the PSU8600.
  2. Right-click the basic device SITOP PSU8600 and select the "Change device" item in the pop-up menu. The "Change device" dialog opens.
       

    Fig. 5 

  3. In the hardware catalog you select the basic device SITOP PSU8600 with firmware V1.4 and apply the setting with "OK".
     

    Fig. 6
      
  4. Right-click the buffer module BUF8600 4s/40A or BUF8600 10s/40A and select the item "Change device" in the pop-up menu. The "Change device" dialog opens.
  5. In the hardware catalog you select the buffer module BUF8600 4s/40A or BUF8600 10s/40A with firmware V1.4.
     

    Fig. 7
     
  6. Load the changed configuration into your S7-CPU.
  7. Switch off the power supply.
  8. If the buffer module BUF8600 4s/40A or BUF8600 10s/40A is buffered empty and the PSU8600 is switched off, switch the power supply back on again.
  9. As soon as the buffer module is charged to the set threshold value (default: 85%) the message "Buffering mode not possible due to low charge" goes away.

Further Information
Detailed information about SITOP PSU8600, SITOP UPS8600 and SITOP BUF8600 is available in the manual in Entry ID 105867947.

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