Omega Vehicle Security 1500 User Manual

Page of 256
Hardware
7-13
Digital Filtering:
 
Averages 32 samples at 50/60 Hz for line cycle noise rejection (VDC measurements)
Voltage Range
2
, Accuracy
3
 and Resolution:
 
±100 mV    
±
 0.02%        3.05 
µ
V/bit
 
±1 V           
±
 0.02%        30.5 
µ
V/bit
 
±5 V           
±
 0.02%        153 
µ
V/bit
 
±10 V         
±
 0.02%        306 
µ
V/bit
Note 1:
Accuracy is based on 18 to 28
°
C, 1 year; includes cold junction compensation; excludes thermocouple errors;
thermocouple readings based on NIST Monograph 175.  Resolution given is the typical value.  Add ±5°C for common
mode voltages greater than 25 VAC.
Note 2:
Voltage range is maximum peak-to-peak signal for AC volts.
Note 3:
For AC voltages where the frequency of the input signal is an integer multiple of the AC line cycle ±1%; with line cycle
integration enabled.
Note 4:
Specified for coupling impedance >30 M
Ω
 and common mode frequency < 60 Hz.  300 VDC or 300 VAC peak before
equipment damage occurs.
Note 5:
There is a 4700 pico-farad, polypropylene capacitor connected across the input terminals of each channel.  This
capacitor filters input noise when measuring signals from thermocouples.  When the circuit card is set to the ±100 mV
range, the capacitor reacts with user source impedance to form a low pass filter. The filter pole frequency is:
1/(2*pi*(RSHI + RSLO)*4700 * 10
-12
), where RSHI and RSLO are the source resistance of the input leads.