General status bits (s0 through s7), Open-circuit flag bits (oc0 through oc7) – Rockwell Automation 1769-IT6 Compact I/O 1769-IT6 Thermocouple/mV Input Module User Manual
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Rockwell Automation Publication 1769-UM004B-EN-P - March 2010
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Module Data, Status, and Channel Configuration Chapter 4
General Status Bits (S0 through S7)
Bits S0 through S5 of word 6 contain the general status information for channels
0…5, respectively. Bits S6 and S7 contain general status information for the two
CJC sensors (S6 corresponds to CJC0, S7 to CJC1). If set (1), these bits indicate
an error (over- or under-range, open-circuit, or input data not valid condition)
associated with that channel. The data not valid condition is described below.
Input Data Not Valid Condition
The general status bits S0 to S5 also indicate whether the input data for a
particular channel, 0…5, is being properly converted (valid) by the module.
This ‘invalid data’ condition can occur (bit set) when the download of a new
configuration to a channel is accepted by the module (proper configuration), but
before the A/D converter can provide valid (properly configured) data to the
1769 bus master/controller. The following information highlights the bit
operation of the input data not valid condition.
1.
The default and module power-up bit condition is reset (0).
2.
The bit condition is set (1) when a new configuration is received and
determined valid by the module.
The set (1) bit condition remains until the module begins converting
analog data for the previously accepted new configuration. When
conversion begins, the bit condition is reset (0). The amount of time it
takes for the module to begin the conversion process depends on the
number of channels being configured and the amount of configuration
data downloaded by the controller.
3.
If A/D hardware errors prevent the conversion process from taking place,
the bit condition is set (1).
Open-circuit Flag Bits (OC0 through OC7)
Bits OC0 through OC5 of word 6 contain open-circuit error information for
channels 0…5, respectively. Errors for the CJC sensors are indicated in OC6 and
OC7. The bit is set (1) when an open-circuit condition exists
for more information on open-circuit operation.
TIP
If the new configuration is invalid, the bit function remains reset
(0) and the module posts a configuration error.
.