Rockwell Automation 1769-IR6 Compact I/O 1769-IR6 RTD/Resistance Input Module - Manual (Page 48)

48 Rockwell Automation Publication 1769-UM005B-EN-P - March 2012
Chapter 4 Module Data, Status, and Channel Configuration
General Status Flag Bits (S0…S5)
Bits S0…S5 of word 6 contain the general status information for channels
0…5, respectively. This bit is set (1) when an error (over- or under-range,
short-circuit, open-circuit, or input data not valid) exists for that channel. The
error conditions of the General Status bits are logically ORed. Therefore, the
user control program determines which condition is setting the general status
bit by viewing the following bits: open-circuit, over-range, or under-range. The
data not valid condition is described below.
Input Data Not Valid Condition
The general status bits S0…S5 also indicate whether or not 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 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
configuration. When conversion is complete, the bit condition is reset
(0) by the module. 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).
TIP If the new configuration is invalid, the bit function
remains reset (0) and the module posts a configuration
error. See Configuration Errors on page 86.