| abstract |
A safety circuit system for a DC driven device for use with a fluid delivery system includes a first voltage potential DC power line, a second voltage potential DC power line, a controller and a safety circuit. The first voltage potential DC power line is coupled to provide a first voltage potential to the DC driven device, and the second voltage potential DC power line is coupled to provide a second voltage potential to the DC driven device such that the second voltage potential is different relative to the first potential. The controller controls at least the first voltage potential on the first voltage potential DC power line. The safety circuit has an enable state and a disable state, in which the default state is the disable state. The safety circuit is coupled to the controller, and the controller controls the safety circuit to place the safety circuit in the enable state independently of controlling the first voltage potential on the first voltage potential DC power line. The safety circuit is operatively coupled to at least one of the first and second voltage potential DC power lines to inhibit DC flow and operation of the DC driven device when the safety circuit is in the disable state and to permit DC flow and operation of the DC driven device when the safety circuit is in the enable state such that the operation of the DC driven device will occur when the safety circuit is in the enable state. In one version the DC driven device is a DC motor in an infusion pump, while in other versions the DC driven device is a gas generator in an infusion pump. Preferably, the safety circuit is controlled by an AC signal from the controller such that the safety circuit is enabled by the AC signal to permit DC flow and enable the forward motion of the DC motor while the AC signal is provided by the controller. |