Based on the nomenclature , this guide pertains to the Festo CMMO-ST (Controller for Motorized Motion – Servo/Stepper Technology) series, specifically a model equipped with an integrated Digital I/O (DIOP) option.
The CMMO-ST error system is categorized into classes. Understanding the class helps determine the severity.
: A single flashing point typically indicates the bootloader is active or firmware is being read from a memory card. Error Codes : These are displayed in the format E x x y . E : Signifies an error. xx : The two-digit main index of the error. y : The single-digit sub-index.
Note: Since “cmmo-st-c5-1-diop” does not match a standard commercial HVAC, chiller, or VFD model from major brands (Carrier, Trane, Daikin, Mitsubishi, York), this post treats it as a (possibly a chiller module, PLC, or OEM board). I have written the post to be useful for technicians encountering an unknown or legacy error code system. cmmo-st-c5-1-diop error codes
Mismatch in the Safe Torque Off signals or diagnostic failures. Significant Individual Codes
The motor cannot reach the target position (stalling, mechanical jam). Safety Function (STO)
) to access the most current technical descriptions and error lists. Verify STO Logic: Based on the nomenclature , this guide pertains
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Keep this guide printed inside your control cabinet door. When those LEDs start blinking, you’ll know exactly what action to take.
The model nomenclature dictates how the device communicates and trips diagnostics: CMMO-ST : Motor controller for stepper motors. C5 : 5A nominal output current. 1 : 24 V DC input voltage supply. : A single flashing point typically indicates the
Here, you will see a timestamped list of with extended details, such as:
Leave the exact code (e.g., “E-33”) in the comments, and I’ll help you decode it.
The controller uses specific code letters (A to G) to define how the motor should behave when a particular error occurs. These responses are parameterizable and determine the stop characteristics and whether the output stage is turned off.
: Record the full 4-digit code directly from the 7-segment display before resetting power.
These errors impact closed-loop tracking by highlighting physical wiring or feedback issues.