AD7175-2单通道转换出现欠量程错误是什么原因？

目前一个项目采用了24bit的AD7175-2，在正常采样信号是会经常出现变成0值，状态寄存器的第六位置位，指示超量程或者欠量程错误，而且出现错误时除非把AD再次初始化否则不能正常采样。请教大家这个是什么原因？只用AD0通道采样，非差分。采样信号来自三节1.5V电池分压。
下面是AD7175的寄存器初始化配置：
{0x00,0x00,1},//现状_登记
{0x01, 0x800, 2}, // ADC_ mode_ 注册
{0x02, 0x01000, 2}, // Interface_ Mode_ Register
{0x04, 0x0000, 3}, // 数据_ 注册
{0x05,0x0000,2},//IOCon_登记
{0x07,0x0000,2},//ID_st_reg
{0x10, 0x8016, 2}, //CH_Map_1 REF-作为AIN-
{0x11,0x0000,2},//CH_地图_2
{0x12,0x0000,2},//CH_马普_3}
{0x13,0x0000,2},//CH_地图_4}
//#0x20,0x1300,2}//Setup_Config_1
{0x20,0x0300,2},//Setup_Config_1 BI_UNIPOLAR0
{0x21, 0x1300, 2}, // Setup_ Config_ 2
{0x22,0x130,2},//Setup_Config_3}//Setup_Config_3
{0x23,0x130,2},//Setup_Config_4}//Setup_Config_4
{0x28, 0x020A, 2}, // filter_ Config_ 1
{0x29,0x020,2},//Filter_Config_2}
{0x2a,0x020,2},//Filter_Config_3}//Filter_Config_3
{0.x2b, 0x0200, 2}, /// Filter_ Config_ 4
{0x30, 0, 3}, // offset_ 1
{0x31, 0, 3}, // offsets_ 2
{0x32, 0, 3}, // offset_ 3
{ 0x33, 0, 3}, // offset_ 4
{ 0x38, 0, 3}, // Gain_ 1
{ 0x39, 0, 3}, // Gain_ 2
{0.x3a, 0, 3}, // Gain_ 3}
{0.x3b, 0, 3}, // Gain_ 4
{0xFF,0,1}//通讯_登记