Notes from Matjaz on the IP470: I was surprised that the ip470 initialization does not include settings about the channel direction, so I did some research. In the IP470 manual it states that:" Each channel can be used as either an input, an output, or an output with readback capability." It further states that "Individual I/O ports may be masked from writes to the port when the port is used for input. This helps prevent contention errors." It sounds from the manual that masking is more of an option than a requirement. I did some measurements and these are the findings: 1) You can set and read all channels. 2) If you turn ON an input channel (sending a command) that is connected to the power supply and is in an OFF state (PS voltage above 1.33 V), the voltmeter measuring the voltage between the input pin and the IP470 ground turns off automatically. This probably indicates that something is not right and that you should not set bits that are wired as inputs. 3) You can use some channels on the same port as inputs and some as outputs. I have connected one channel as input and the others as outputs. I was able to change the outputs and read the input. You need to make sure that you do not set the input. 4) When the cables are not connected, the voltage on the pins is 5V and they are all in the OFF state. If you connect the input to the power supply (one lead to the pin, the other to the IP470 ground), the voltage drops to 0.4 V and the state goes to ON. 5) The transitions from ON to OFF happen in the region between 1.32 V and 1.38 V. The manual talks about hysteresis, but I saw flickering. The region limits are where the changes happen at around 1/min. 6) All outputs go to OFF (5V) at IOC reboot.