TsctlAIOChannelVoltageRangeDesc

This function sets the voltage range for the specified channel ch to be between low and high. If the channel is not currently enabled, then the voltage range will not take effect until ChannelEnable is called for this channel. Otherwise the change will take place immediately.

Upon failure, a negative value is returned to indicate that the requested voltage range cannot be set. If the range will not take effect immediately then this cannot occur, so the current range will be returned, since the one passed has not yet taken effect.