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Allen-Bradley HMIs
• Channel number: in the range 1 to 7 (1=V1, 2=I1, 3=V2, 4=I2,
5=V3, 6=I3, 7=I4)
• Block number: block number of the data contained in the table.
See above.
• Transient capture identifier: range 0 to 30,000, rolls over to 0
• Transient capture data points: see below
Transient Capture Data Points
The results table contains 20 data points for optional DeviceNet
communications or 50 data points for all other communications
options. Data points are numbered 1 to 20 or 1 to 50 in each block.
The block number ranges from 1 to 70 for DeviceNet and 1 to 28 for
all other communications options. The client calculates each data
point's place in the transient capture using the following formula:
N
datapoint_capture
N
= the sequence number of the data point in the capture channel
datapoint_capture
N
= the block number
block
N
= the data point number (1 to 20 or 1 to 50) in the current read
datapoint_this_read
The total number of data points is 1400. Each data point is expressed
in calibrated analog-to-digital (A/D) converter counts with a resolution
of 8192 (13-bit w/sign). A client may calculate the primary-side
instantaneous voltage or current magnitude of each data point using
the following formula:
M
=
i
M
= instantaneous value of the voltage or current data point
i
M
= max rms magnitude
(max rms)
= 399.0 line-to-neutral volts for channels 1, 3 and 5
= 691.1 line-to-line volts for channels 1, 3 and 5
=10.6 amperes for channels 2, 4, 6 and 7
R
= maximum resolution
max
= 8192 for 13-bit w/sign
N
= PT or CT ratio
t
= PT or CT primary / PT or CT secondary
M
= value of the data point from Table A.46
data
For example, consider the following capture:
• PT primary = 13.8 kV
• PT secondary = 120 V
(
)
=
N
–
1
+
N
block
datapoint_this_read
•
M
2
(
)
max rms
•
•
------------------------------------- -
N
t
R
max
Publication 1404-UM001D-EN-E - October 2004
Advanced Features
8-23
M
data
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