A01953 — CU SYNC: Synchronization not completed

A01953 is an alarm that appears when the drive system is switched on: the synchronization between the drive's internal clock cycles was started but was not completed within the selected time tolerance. The manuals title the message CU SYNC: Synchronization not completed. The message value is the alarm value held in r2124, interpreted as a decimal number; the manual assigns it to internal Siemens troubleshooting only, so it names no action for the technician.

• After the drive system is switched on, the synchronization between the basic clock cycle, the DRIVE-CLiQ clock cycle and the application clock cycle was started but was not completed within the selected time tolerance.
• The manuals differ only in which clocks they name: the entries for the G130, G150, S120 and S150 include the DRIVE-CLiQ clock cycle, while the G120 entry names the basic clock cycle and the application clock cycle.
• The manual names one situation in which the alarm can show up again: after the drive sampling times were changed, on systems where a Terminal Module 31 (TM31) is being used.

1. Carry out a POWER ON (switch-off/switch-on) for all components.
2. If the alarm occurs again after the drive sampling times were changed and a Terminal Module 31 (TM31) is being used, follow the manual's wording: the sampling times (p0115, p4099) should be set as integer multiples to the drive clock cycles (p0115). This second step is printed for the G130, G150, S120 and S150 entries; the G120 manual gives only the POWER ON.

• The manual prints the message value as the placeholder %1 and ties it to the alarm value in r2124.
• r2124 is interpreted as a decimal number.
• Per the manual, this alarm value is only for internal Siemens troubleshooting — no decoding is given that a technician could act on.

• r2124 — alarm value of this message; interpret it as a decimal number. The manual assigns it to internal Siemens troubleshooting only, so there is nothing to set here.
• p0115 — sampling time for supplementary functions; in the TM31 case it is one of the sampling times that must be set as integer multiples of the drive clock cycle (p0115).
• p4099 — TM31 inputs/outputs sampling time; like p0115, set it as an integer multiple of the drive clock cycle (p0115) when the alarm follows a change of the drive sampling times and a TM31 is used.

No acknowledgement is required for this alarm. The manual's remedy is the POWER ON (switch-off/switch-on) of all components; if the alarm comes back after the restart, work through the checks above — with a Terminal Module 31 (TM31) connected, in particular the integer-multiple setting of the sampling times (p0115, p4099).