A method for optimizing the parameter setting of at least one energy supply parameter of a field device power supply module. The field device power supply module is, in such case, connected exclusively to one field device. The connected field device is supplied with electrical energy by the field device power supply module. In the method, the system composed of field device and field device power supply module is operated and a parameter setting of at least one energy supply parameter varied. In such case, the operation of the field device is monitored. Parameter settings are ascertained, in the case of which a relatively low energy consumption of the field device and simultaneously a safe operation of the field device can be realized in the relevant operational phase.