Programmable logic controller, and base unit and module units thereof

A base unit of a programmable logic controller provided with the base unit and a plurality of module units to be connected to the base unit, the base unit comprising:

• a substrate having a plurality of base-side connectors and electrically connecting the plurality of module units via the plurality of base-side connectors;
• a base case having openings through which the plurality of base-side connectors are exposed and housing the substrate;
• at least one holding part to hold a connection unit which is one of the plurality of module units by being engaged with an engagement mechanism of the connection unit;
• an elastic member to exert a force in a first direction, which is a direction in which the connection unit moves away from the base unit, for pressing the engagement mechanism of the connection unit against the at least one holding part of the base unit;
• and
• a sealing member to seal a gap between a fitting tenon of the module case of the connection unit and the base case, the fitting tenon being formed such that it surrounds the module-side connector of the connection unit to be connected to one of the plurality of base-side connectors,
• wherein
• the at least one holding part is provided in plurality to form a pair, and
• the pair of holding parts has at least one slant face inclined with respect to the first direction such that the force exerted by the elastic member is applied in a second direction intersecting the first direction.

A module unit of a programmable logic controller provided with:

• a base unit having a substrate with a plurality of base-side connectors, a base case with an opening through which one of the plurality of base-side connectors is exposed and housing the substrate, and at least one holding part to hold another unit;
• and the module unit to be connected to the base unit, the module unit comprising:
• a module-side connector to be connected to one of the base-side connectors of the base unit;
• an engagement mechanism to be detachably engaged with the at least one holding part of the base unit;
• a module case having a fitting tenon formed in such a manner as to be fitted with the base case and to surround the module-side connector;
• an elastic member to exert a force in a first direction, which is a direction in which the module unit moves away from the base unit, for pressing the engagement mechanism of the module unit against the at least one holding part of the base unit;
• and
• a sealing member to seal a gap between the base case and the fitting tenon of the module case,
• wherein
• the at least one holding part is provided in plurality to form a pair, and
• the pair of holding parts has at least one slant face inclined with respect to the first direction such that the force exerted by the elastic member is applied in a second direction intersecting the first direction.