What Modbus functions are supported by Sealevel products?

Many Sealevel products support Modbus including SeaI/O modules, SeaDAC modules, eI/O modules, SeaRAQ modules, and SeaConnect modules. That said, individual modules support different Modbus functions.
 
This Sealevel Software documentation page enumerates all the relevant Modbus functions for the different supported products from the categories above: https://www.sealevelsoftware.com/documentation/seamax/win/modbusbreakdown.html