Code 27350: F_DP: %1 communication, co nnection %2 reports error %3
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical F_DP: %1 communication, co nnection %2 reports error %3 alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Parameters: %1 = Type of communication %2 = Name or DP_DP_ID of the communication relationship %3 = Error code Definitions: The F_DP communication with the external communi cation partner is disturbed, and the programmed error reaction is $A_FSDP_/FRDP_ERR_REAC = 0 or 1. The communication type is displayed in %1: %1 = F_SENDDP %1 = F_RECVDP The name or the DP_DP_ID (identifier) of the SPL connection is displayed in %2. The detected cause of the er ror is displayed in %3. %3 = SN: An error has been detected in the message sequence. %3 = CRC: A CRC error has been detected. %3 = TO: The parameterized co mmunication timeout was exceeded. All values stated for %3 can also be displayed in combination according to the fault profile. Reaction: Mode group not ready. NC Start disable in this channel. Interface signals are set. Alarm display. NC Stop on alarm. 1. F_SENDDP/F_RECVDP: system variable $A_FSDP/FRDP_ERROR = TRUE 2. F_SENDDP/F_RECVDP: system variable $A_FSDP/FRDP_DIAG <> 0 3. F_RECVDP: system variable $A_FRDP_ACK_REQ = TRUE 4. F_RECVDP: Output of the substitute va lues defined in system variable $A_FRDP_SUBS 5. An alarm and Stop D/E are also triggered with the programmed error reaction $A_FSDP_/FRDP_ERR_REAC = 0 Remedy: Check the PROFIBUS communication and the communication partner. Note: A user acknowledgment via DB18.FRDP_ACK _REI only acknowledges the F_DP communication. The alarm is still displayed and mu st be acknowledged separately via NC RESET. Note to %3 = LS: Internal system er ror, can only be eliminated by PowerOn. Program Continuation: Clear alarm with the RESET key. Restart part program
Source: SINUMERIK 840D sl / 840Di sl / SINAMICS S120 Diagnostics Manual (DAsl, 03/2009)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Siemens SINUMERIK 840D CNC Alarms
Siemens controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 27350 on the SINUMERIK 840D CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Siemens's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 4014 Siemens SINUMERIK 840D CNC codes.
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