Allen-Bradley Compact 1769-IR6, Руководство пользователя

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Publication 1769-UM005A-EN-P
Module Data, Status, and Channel Configuration 4-3
Input Data Values
Data words 0 through 5 correspond to channels 0 through 5 and contain
the converted analog input data from the input device.
General Status Flag Bits (S0 to S5)
Bits S0 through S5 of word 6 contain the general status information for
channels 0 through 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 to S5 also indicate whether or not the input data
for a particular channel, 0 through 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).
NOTE
Status bits for a particular channel reflect the configuration
settings for that channel. To receive valid status, the
channel must be enabled and the module must have
stored a valid configuration word for that channel.
NOTE
If the new configuration is invalid, the bit function
remains reset (0) and the module posts a
configuration error. See Configuration Errors on
page 5-5.
AB PLCs