Many design considerations for the output module are common to the input module. In general, resolution of the DAC is a main consideration with 16 bit DACs being preferred. Settling time of the DAC must also meet system requirements. Low offset and gain errors can reduce the need for calibration and low output drift over temperature can greatly reduce system error. Outputs must be capable of driving up to +/-15 V and have the flexibility of using the same component for driving current or voltage outputs. Short circuit protection and open circuit detection are needed and integrating these functions creates significant value. As with input modules, protection against transients, surges and electromagnetic interference (EMI) is required to meet IEC and other standards. Accurate voltage references, power supplies and low noise LDOs allow increased system precision. Finally, isolation, both digital for the SPI interface and analog for power is required.