SYSTEM AND METHOD FOR DETECTING PRESENCE OF AN INFUSION CARTRIDGE IN AN INFUSION PUMP
Infusion devices, systems, and methods can detect a presence or absence of an infusion cartridge in an infusion pump. Embodiments may include a loading sequence, recording loading pulse width modulation (PWM) commands applied to an infusion pump motor during the loading sequence, setting a value of threshold PWM commands based on the commands applied during the loading sequence and comparing values of operational PWM commands applied during pumping operations to the value of the threshold PWM commands. If the value of the operational PWM commands drops below the threshold by a predetermined amount, a missing infusion cartridge warning may be generated.
1 . A method for detecting a presence of an infusion cartridge in an infusion pump, comprising:
installing an infusion cartridge in an infusion pump;
initiating an infusion cartridge loading sequence;
recording loading pulse width modulation (PWM) commands applied to an infusion pump motor during the loading sequence;
setting a value of threshold PWM commands;
comparing values of operational PWM commands that are applied during pumping operations to the value of the threshold PWM commands; and
generating a missing cartridge indication if the value of the operational PWM commands drop below the value of the threshold PWM commands by a predetermined amount.
2 . The method of claim 1 wherein the value of threshold PWM commands is an average value of the loading PWM commands.
3 . The method of claim 1 wherein values of operational PWM commands are average values of PWM commands of each subsequent motor move during a pumping cycle.
4 . The method of claim 1 , wherein the PWM commands are uniform amplitude voltage pulses.
5 . The method of claim 1 , where the predetermined amount is based on a pumping speed of the pumping operations.
6 . The method of claim 1 wherein the predetermined amount is between 20% and 40% of the threshold.
7 . The method of claim 1 . wherein the predetermined amount is between 40% and 60%.
8 . An infusion system configured for detecting a presence of an infusion cartridge, comprising:
an infusion cartridge comprising:
a delivery mechanism for effectuating a delivery of fluid, the delivery mechanism including;
an axial bore, and
a spool disposed within the axial bore and axially translatable within the axial bore, and
a drug delivery reservoir for storing fluid; and
an infusion pump comprising:
a drive mechanism including a motor operatively coupleable to the spool and configured to impart controlled axial movements of the spool that move fluid from the infusion cartridge to an outlet port;
a processor, the processor coupled to a memory configured for receiving input data from the memory and using input data for generating operational parameters for the infusion system;
the memory adapted to receive and store input data coupled to the processor and configured for communicating that data to the processor; and
programming stored in the memory for retrieval by the processor to control a closed loop motor control algorithm, the closed loop motor control algorithm configured to generate pulse width modulation (PWM) commands to operate the motor of the drive mechanism, wherein when values of the PWM commands fall below a threshold value by a predetermined amount an absence of the infusion cartridge warning is generated.
9 . The infusion system of claim 8 , further comprising a user interface configured for displaying a request for a user to input data, wherein the display is further configured for receiving user input data in response to the request and communicating that data to the memory.
10 . The infusion system of claim 9 , wherein the user interlace is further configured to display the absence of the infusion cartridge warning.
11 . The infusion system of claim 8 , in which the closed loop motor control algorithm is a velocity loop algorithm.
12 . The infusion system of claim 8 , in which value of the PWM commands is proportional to a load on the motor of the drive mechanism.
13 . The infusion system of claim 8 , wherein the threshold value is determined based off of PWM commands applied to the pump motor during a loading sequence of an infusion cartridge.
14 . The infusion system of claim 8 , wherein the PWM commands are uniform amplitude voltage pulses.
15 . The infusion system of claim 8 , where the predetermined amount is based on a pumping speed of the pumping operations.
16 . A method of calibrating an infusion pump that utilizes an infusion cartridge, comprising:
installing an infusion, cartridge in an infusion pump;
initiating an infusion cartridge loading sequence;
recording loading pulse width modulation (PWM) commands applied to an infusion pump motor during the loading sequence; and
setting a value of threshold PWM commands.
17 . The method of claim 16 , wherein the value of threshold PWM commands is an average value of the loading PWM commands.
18 . The method of claim 16 , wherein the PWM commands are uniform amplitude voltage pulses.
19 . The method of claim 16 , wherein the threshold value is variable based on a speed of subsequent pumping operations of the infusion pump.