Allen-Bradley Compact I/O 1769-ADN DeviceNet, Руководство пользователя

Страница: 42 / 204

Publication 1769-UM001B-EN-P - October 2002
2-18 How Communication Takes Place and I/O Image Table Mapping
1769-IR6 RTD/Resistance
Input Module
Input Data
The first six words (0 to 5) of the input data file contain the analog
RTD or resistance values of the inputs. Words 6 and 7 provide
sensor/channel status feedback for use in your control program as
shown below.
Wo
rd
Bit Position
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 RTD/Resistance Input Data Channel 0
1 RTD/Resistance Input Data Channel 1
2 RTD/Resistance Input Data Channel 2
3 RTD/Resistance Input Data Channel 3
4 RTD/Resistance Input Data Channel 4
5 RTD/Resistance Input Data Channel 5
6 Not Used OC5 OC4 OC3 OC2 OC1 OC0 Not
Used
S5 S4 S3 S2 S1 S0
7 U0 O0 U1 O1 U2 O2 U3 O3 U4 O4 U5 O5 Not Used
Sx = General status bit for channels 0-5. This bit is set (1) when an error (over-range, under-range, open-circuit,
or input data not valid) exists for that channel. An input data not valid condition is determined by the user
program. This condition occurs when the first analog-to-digital conversion is still in progress, after a new
configuration has been sent to the module. Refer to the
Compact
™
I/O RTD/Resistance Input Module User
Manual , publication 1769-UM005A-EN-P for additional details.
OCx = Open circuit detection bits indicate an open input circuit on channels 0-5 (OC0 - OC5). The bit is set (1)
when either an open or shorted input for RTD inputs or an open input for resistance inputs is detected.
Short-circuit detection for resistance inputs is not indicated because 0 is a valid number.
Ux = Under-range flag bits for channels 0-5, using RTD inputs only. These bits can be used in the control
program for error detection. There is no under-range error for a direct resistance input, because 0 is a valid
number.
Ox = Over-range flag bits for channels 0-5, using either RTD or resistance inputs. These bits can be used in the
control program for error detection.