The information you provided, SAN3-40, SAN3-40M -3, suggests that you're looking for details about two potentially related Yokogawa products: SAN3-40 and SAN3-40M. Here's what I can tell you based on my search:

**Manufacturer:** Yokogawa - A reputable manufacturer of industrial automation and measurement instruments.

**Finding Information:**

Obtaining specific details about these products might be challenging due to:

* Limited online presence of information for these exact model codes.
* Potential obsolescence of the models (indicated by the "-3" suffix, which could signify a revision number).

Here are some suggestions for your search:

* **Yokogawa Website:** Search the Yokogawa website ([https://www.yokogawa.com/about/](https://www.yokogawa.com/about/)) using the codes "SAN3-40" and "SAN3-40M". They might have archived product information or datasheets for discontinued models.
* **Industrial Automation Parts Suppliers:** Some online retailers specializing in industrial automation parts might list these models (use caution regarding accuracy and condition). Be sure to double-check the model codes before purchasing.
* **Industrial Automation Forums:** Online forums or communities dedicated to industrial automation or Yokogawa instruments might have discussions about these models. Search for "Yokogawa SAN3-40" or "Yokogawa SAN3-40M" to see if relevant information can be found.

**Possible Product Functions (educated guess based on model names and Yokogawa's product lines):**

* **SAN3-40:**  Could be a pressure transmitter or sensor based on Yokogawa's SAN series pressure transmitters. These are instruments used to measure pressure in various industrial processes.
* **SAN3-40M:** The "M" might indicate a variation of the SAN3-40, possibly with a different pressure range or mounting style.

**Additional Notes:**

* The "-3" suffix likely represents a specific revision of these models. Without further information, it's difficult to determine the exact differences from the base models.
* Working with industrial automation systems often requires knowledge of:
    * Process measurement principles (for pressure measurement in this case)
    * Yokogawa instruments or similar industrial automation equipment

If you can provide more context about how you encountered these codes (e.g., a specific process plant manual or a list of spare parts), it might help narrow down the search for relevant information.