User manual
905U Wireless I/O Module User Manual
105S Serial I/O Module
Page 56 © October 2001
low volts status (‘1’ for low volts ‘0’ for OK). "S" is the set-point status.
P CNT, AI1, AI2, P RATE, and VBATT each represent 16 bit values, displayed as four hexadecimal
digits.
P CNT is the current value of the pulsed input counter. This value should increment each time ‘DI 1’
turns from OFF to ON. P RATE displays the current pulse rate at DI1. This value is scaled according
to the MAXRATE value configured (0 Hertz is displayed as 4000, and the maximum rate is displayed
as C000).
AI1 and AI2 represent the value for the two analog inputs. Full scale input (20 mA) is displayed as
C000, 4mA is displayed as 4000, and 0ma is displayed as 2000. Analog inputs are filtered digitally
with a time constant of 1 second, so a sudden change in the analog input current will result in a slower
change in displayed analog value, finally settling at the new value.
A guide to translate the displayed value to the analog input current is provided below.
Add together the figures corresponding to each digit in each position to
determine the current (mA)
e.g. displayed value 3456 = 2.000+0.500+0.039+0.003
= 2.542mA
Digit Leftmost
position
Next position Next position Rightmost
position
0 - 0.000 0.000 0.000
1 - 0.125 0.008 0.000
2 0.000 0.250 0.016 0.001
3 2.000 0.375 0.023 0.001
4 4.000 0.500 0.031 0.002
5 6.000 0.625 0.039 0.002
6 8.000 0.750 0.047 0.003
7 10.000 0.875 0.055 0.003
8 12.000 1.000 0.063 0.004
9 14.000 1.125 0.070 0.004
A 16.000 1.250 0.078 0.005
B 18.000 1.375 0.086 0.005
C 20 1.500 0.094 0.006
D 22 1.625 0.102 0.006
E - 1.750 0.109 0.007
F - 1.875 0.117 0.007
VBATT is the current internally derived battery voltage. 4000 corresponds to 8 Volts, C000 represents
16 volts. A quicker method is use the calculation :
Battery voltage (volts) = ½ I + 6, where I is the mA value determined from the above table using
VBATT. For example, a value of VBATT of A000 gives an I value of 16mA from the above table.
The battery voltage corresponding to this is 14V (or ½ x 16 + 6).