Our group developed an MR compatible PET insert system for simultaneous PET/MR imaging of small animal in a 7T animal MR imaging system. The PET insert uses 16 detectors based on SensL SPMArray4B SiPMs and dual-layer offset LYSO crystal blocks.This thesis focuses on the development and implementation of a control system designed to power the PET detector modules, allow compensation for the SiPM gain variation caused by changes in temperature and provide a signal conditioning intermediary between the PET detector modules and the OpenPET data acquisition system. First, the control system is functionalized by creating the firmware and software. Second, the system components are characterized for a temperature range of 12°C to 28°C on the bench top. Based on these characterization data, a temperature based feedback control system is developed to compensate for the SiPM gain variation. The feedback system is tested by placing the PET insert in a temperature chamber continuously cycling between 15°C and 25°C. When operated without the feedback control system, the photopeak position of the detectors varied by ±4.9%, while with the feedback control system the variability is reduced to ±1.1%. Last, the control system is evaluated for the PET insert operating inside the MR system for simultaneous PET/MR operation. To evaluate the effectiveness of the feedback system, an MR sequence is applied for 68 minutes which increased the system temperature by ∼8°C. When operated without the feedback control system, the average photopeak position decreased by ∼14%, while with the feedback control system operating, the variations in the average photopeak position remained within ±1.5%.