Method and apparatus for logical addressing in a modular patient care system

A modular patient care system having a plurality of units detachably coupled to form a linear array of units, said linear array having a originating end and a terminating end, each of said units having an originating side facing said originating end and a terminating side facing said terminating end, said plurality of units comprising:

• an interface unit for providing a user interface to said system, said interface unit being capable of providing sequential logical ID's;
• a plurality of functional units, each functional unit having a unique resettable logical ID;
• and
• a communications bus formed by said linear array of units for allowing each functional unit to communicate with said interface unit and receive commands therefrom;
• wherein each functional unit further comprises:
• means for detecting a first signal provided by an adjacent originating side unit, said first signal having a first value or a second value different from said first value;
• means for providing said first signal to an adjacent terminating side unit;
• means for generating a second signal, said second signal being equal to
• (a) said first value if the functional unit is at said originating end of the linear array, or
• (b) the value of said first signal provided by said adjacent originating side unit if the functional unit is not at the originating end of the linear array;
• means for setting said first signal to said second value upon receiving a first command from said interface unit;
• means for receiving one of said sequential logical ID's from said interface unit upon detecting said second signal to be equal to said first value after having received said first command;
• means for setting said first signal equal to said first value after having received said logical ID;
• whereby
• said patient care system is capable of assigning said sequential logical ID's to said functional units according to their sequential positions in said linear array.

A modular patient care system having a plurality of units detachably coupled to each other to form a linear array, said linear array having a originating end and a terminating end, said units each having an originating side facing said originating end and a terminating side facing said terminating end, said linear array comprising:

• an interface unit for providing a user interface to said system;
• a plurality of functional units, each functional unit being capable of providing patient therapies or monitoring, each functional unit having a unique resettable logical ID, each functional unit comprising:
• a communications bus portion for forming a common communications bus;
• a unit detect bus portion for forming a unit detect bus;
• means for providing an id.sub.-- enable.sub.-- out signal to a unit abutting said terminating side, said id.sub.-- enable.sub.-- out signal having a value ENABLE or DISABLE;
• means for generating an id.sub.-- enable.sub.-- in signal, wherein said id.sub.-- enable.sub.-- in signal is equal to
• (a) ENABLE if the functional unit is at said originating end of said linear array, or
• (b) the id.sub.-- enable.sub.-- out signal of a unit abutting said originating side otherwise;
• means for receiving commands from said interface unit over said communications bus;
• means for pulling down said unit detect bus to a LOW state and setting said.sub.-- id enable.sub.-- out signal to DISABLE responsive to a first command from said interface unit;
• means for detecting the state of said id.sub.-- enable.sub.-- in signal;
• means for receiving a unique logical address from said interface unit upon (1) having received said first command, and (2) detecting the state of id.sub.-- enable.sub.-- in to equal ENABLE;
• means for setting said logical ID equal to said unique logical address;
• and
• means for setting said id.sub.-- enable.sub.-- out signal to ENABLE and for releasing said unit detect bus upon setting said logical ID;
• whereby
• said patient care system is capable of assigning sequential logical ID's to said functional modules according to their respective positions in said linear array.

In a modular patient care system having a plurality of units detachably coupled to form a linear array of units having an originating end and a terminating end, each unit having an originating side facing said originating end and a terminating side opposite said originating end, the linear array of units comprising an interface unit for providing sequential logical ID's and a plurality of functional units requiring an assignment of a one of said sequential logical ID's, a method comprising the steps of:

• generating a value ENABLE or DISABLE at an ID enable in lead of each functional unit;
• transmitting a sequential logical ID to all functional units over a common communications bus formed by functional units and the interface unit;
• receiving the sequential logical ID at that functional unit which (1) detects a value ENABLE at its ID enable in lead, and (2) has not yet been assigned a logical ID;
• setting an ID enable out lead of that functional unit to the value ENABLE after receiving the sequential logical ID, for generating the value ENABLE at the ID enable in lead of an adjacent terminating side unit.

A computer-readable medium which can be used to direct an interface unit of a modular patient care system to assign sequential logical unit ID's to a plurality of functional units attached to the interface unit so as to form a linear array of units having an originating end and a terminating end, the interface unit and the functional units each having an originating side facing the originating end and a terminating side opposite the originating side, the computer-readable medium comprising:

• means for directing the interface unit to send commands and receive information over a common communications bus formed by the interface unit and the attached functional units;
• means for directing the interface unit to detect system power-up or the attachment of additional functional units and for directing the interface unit to send a first command to all attached functional units responsive thereto;
• means for directing the interface unit to transmit sequential logical ID's to all functional units over the common communications bus, for receiving by a single functional module which has (1) received the first command, (2) received an enabling signal from an originating side adjacent unit or is the functional unit at the originating end, and (3) has not yet received a logical ID after receiving the first command;
• means for directing the interface unit to detect when all originating side functional units have received logical ID's and for directing the interface unit to transmit an enabling signal to a terminating side adjacent functional unit responsive thereto.

A computer-readable medium which can be used to direct a functional unit of a modular patient care system in receiving a sequential logical unit ID from an interface unit, the modular patient care system having a plurality of functional units attached to the interface unit so as to form a linear array of units having an originating end and a terminating end, the interface unit and the functional units each having an originating side facing the originating end and a terminating side opposite the originating side, the computer-readable medium comprising:

• means for directing the functional unit to pull and then release a unit detect bus upon initial power-up of the functional module, the unit detect bus formed by the functional unit and other functional units, each of the functional units being capable of pulling the unit detect bus to a second voltage, each functional unit also being capable of releasing the originating unit detect bus;
• means for directing the functional unit to sense the voltage of an ID enable in lead, the voltage having the value ENABLE or DISABLE, the ID enable in lead being for connecting to and assuming the value of an ID enable out lead of an adjacent originating unit side functional unit, the ID enable in lead being configured so as to have the value ENABLE if the functional module is at the originating end;
• means for directing the functional unit to receive a first command from the interface unit over a common communications bus and for pulling the unit detect bus to the second value responsive thereto;
• means for directing the functional unit to receive a unique sequential logical ID from the interface unit upon (1) having received the first command, and (2) detecting the voltage of the ID enable in lead to be ENABLE;
• means directing the functional unit to set an internal logical address equal to the value of the sequential logical ID;
• means for directing the functional unit to release the unit detect bus after receiving the logical ID;
• and
• means for directing the functional unit to set the value of the ID enable out lead to ENABLE after receiving the logical ID.