FANUC 31i-B J652: G07 hypothetical-axis interpolation is not machine lock
Check J652 authorization, G07 behavior and the limits of PS0010 diagnosis. A hypothetical axis can still move during manual operation.
Contents
Do not read G07 X0 as confirmation that X has been safely locked. Hypothetical-axis interpolation changes how an axis participates in automatic interpolation; it is neither maintenance isolation nor a general-purpose program test switch. Before transferring a program containing G07, establish why its author needed that axis not to make the corresponding automatic movement.
Identify the control and option first
This article concerns FANUC Series 31i-B, not automatically 31i-B Plus, 0i or other series. The official 2024 function catalogue lists A02B-0327-J652, hypothetical-axis interpolation, on printed page 179. The operating reference is B-64484EN/03, section 4.15, pages 108–109; the alarm reference is note 3 on page 30 of the same manual. “/03” is a document edition, not a software version. A minimum software release and retrofit eligibility for every older machine have not been verified.
Send FANUC or the original builder the complete CNC model, serial number, software series/version, existing option list and intended application. Ask for written confirmation of J652 compatibility, existing authorization and any additional function or configuration requirements. An addition must follow their authorized service process, with machine-specific configuration and acceptance checks. Do not copy an unverified universal enabling parameter: changing a parameter does not purchase or grant an option license.
What G07 controls
G07 α0; designates controlled axis α as hypothetical; G07 α1; cancels that designation. These are syntax descriptions, not ready-to-run machining instructions. One documented application suppresses a circular-plane axis during helical interpolation, producing a sinusoidal path through the remaining movements. G07 is not cylindrical interpolation G07.1; the decimal point changes the function.
The cited edition requires incremental programming and does not support coordinate rotation. Crucially, the hypothetical treatment applies only in automatic operation: manual operation still moves the axis, as does a handwheel interruption. Interlocks, stroke limits and external deceleration can still apply to it. These boundaries make G07 unsuitable as a substitute for safe shutdown, mechanical support or energy isolation.
What PS0010 (IMPROPER G-CODE) can tell you
Page 30 lists a G code without its corresponding option as a cause of PS0010, alongside a code absent from the applicable G-code list. Within the stated scope, missing J652 is therefore a possibility to investigate when G07 is rejected. The alarm alone does not prove that J652 was never purchased. This applies the manual’s general G-code rule; it is not a reported machine test or a universal alarm guarantee across FANUC versions.
Preserve the full alarm, complete block and surrounding program, not just a photograph of the characters G07. Establish whether the actual instruction is G07 or G07.1; check the destination control, active G-code system and matching code table before reviewing official option records. Other G codes in the same block also need checking. Deleting the rejected instruction merely to make the program continue may remove a motion condition on which the original program depends.
Before a program transfer, sketch three cases
Imagine a program transferred from a machine with confirmed J652 to another 31i-B, where execution stops at G07. This is an illustrative diagnostic scenario, not a repair report. Sketch the intended original motion, the motion without hypothetical-axis treatment, and the motion after that treatment ends. If those differences remain unclear, the investigation is not ready for machine trials.
Keep program review separate from authorization review. The first checks axis names, modes, entry and exit points, and fixture clearance; the second establishes that the function is eligible and legitimately configured. Confirmed authorization does not certify that a program suits this machine. A person familiar with the machine must perform acceptance under the builder’s approved procedure, defining safe clearance and stopping conditions for non-cutting verification. Do not experiment on production parts or use manual movement to “prove” that a hypothetical axis is locked.
Sources
The catalogue supports the ordering specification. The operator manual supports syntax, motion boundaries and the general PS0010 rule. The manual below is a third-party mirror of the manufacturer’s document. No successful field repair, minimum software release or authorization bypass is claimed.