Chapter Six
Troubleshooting
man_105_2.9.doc
Page
63
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 analogue inputs. Full scale input (20 mA) is
displayed as C000, 4mA is displayed as 4000, and 0ma is displayed as 2000. Analogue
inputs are filtered digitally with a time constant of 1 second, so a sudden change in the
analogue input current will result in a slower change in displayed analogue value, finally
settling at the new value.
A guide to translate the displayed value to the analogue 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).
