ES51970(6000counts)
DMM Analog front end with Inrush
2. Operating Modes
2.1. Voltage Measurement
MPU send write command to select the voltage measurement function. The Hz mode
measurement is available to be enabled with the ACV function (set AC bit to 1)
simultaneously. The measured signal is applied to VR1 terminal (pin25) through 10MΩ.
See the next table of function command:
F3
0
F2
0
F1
0
F0
0
AC
0
Measurement mode
DCV mode
Read data bytes
D0(0:18), D1(0:9)
0
0
0
0
1
ACV mode
D0(0:18), D1(0:9)
0
0
0
1
1
ACV + Hz mode
D0(0:18), D1(0:9), D3(0:18)
Note1: D0/D1/D2/D3 all are binary format. ASIGN/BSIGN are the sign bit of D0/D1, respectively.
Range control for voltage mode (ACV/DCV)
Q2 Q1 Q0
Full Scale Range
600.0mV
6.000V
Divider Ratio
1
Resister Connection
VR1 (10MΩ)
VR2 (1.111MΩ)
VR3 (101kΩ)
VR4 (10.01kΩ)
VR5 (1kΩ)
0
0
0
0
1
0
0
1
1
0
0
1
0
1
0
1/10
1/100
1/1000
1/10000
60.00V
600.0V
1000V
Frequency range control for ACV+Hz mode
FQ2 FQ1 FQ0 Full Scale Range
0
0
0
0
0
0
1
1
0
1
0
1
60.00Hz
600.0Hz
6.000kHz
60.00kHz
Note: See frequency mode (section 2.8) also
ALARM bit at voltage mode is used for high crest factor (HCF) signal detection. If MPU
check the ALARM status flag active when data and range are stable, it should consider the
making the existing range up to avoid the signal clamping saturation caused by HCF signal.
There is higher peak voltage with lower RMS value for HCF signal. So if the range is up
according to the ALARM bit, MCU should set the lower under-limit counts temporarily to
avoid the ranging unstable for this case.
ver. 2.8
14
12/01/12
CYRUSTEK [ Cyrustek corporation ]
