Rockwell Automation T8402 Trusted Dual 24V dc Digital Input Module - 60 Channel - Manual (Page 18)

Trusted
TM
Module T8402
Issue 13 April 10 PD-T8402 18
Value Description
7 Unknown
6 Over-range
5 Short circuit
4 Closed contact
3 Indeterminate
2 Open contact
1 Open circuit
0 Under-range
Table 7 Rack 2: STATE output descriptions
The input channel has a value 7 (Unknown) when:
1. The input channel cannot be correctly measured by two or more slices of the TMR input
module.
2. The TMR Processor detects a 1-oo-2D channel discrepancy between the appropriate slices
of the Dual input module.
3. The module is simulated (not installed or the TMR Processor cannot communicate with
1-oo-2D slices of the module).
3.2.3. Rack 3: AI
The AI board returns the field loop voltage at the input.
Channel Description
1 Field input channel 1 voltage
2 Field input channel 2 voltage
60 Field input channel 60 voltage
Table 8 Rack 3: Channel Field Voltage
The voltage is the median value taken from the triplicated module. The voltage level is reported as an
integer, with the units being
1 /
512
V. This may be used directly, scaled arithmetically or scaled using the
IEC1131 TOOLSET conversion tables.
When used directly the value may be considered as a signed, fixed-point binary value, i.e.:
Bit
15
14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Sign Integer Fractional
Table 9 Rack 3: Channel Field Voltage bit definitions
To scale the value arithmetically, simply divide the input value by 512 to return the voltage as either a
REAL or INTEGER as required.