Siemens APACS+, Installation And Service Instruction

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SD39EAM-1r4 Installation
September 2005 2-21
Using a more conservative 100ppm drift for 1000 hours as a worst case estimate indicate it would take
greater than 11 years to drift 0.1%.
Long term drifts sigificantly greater than typical would be due to flaws inherent to the manufacturing
process of the individual components or the module itself. APACS screens out even these unlikely
occurrences through multiple additional layers of control. All calibration is done through mathematical
compensation as mentioned above. In addition, the range of compenstion is restricted to prevent
compensation for inherently defective devices. All APACS modules go through environmental stress
screening before functional testing and calibration to precipitate failure of weak components. Finally, all
APACS modules go through an elevated temperature burn-in followed by a final functional verification
including calibration.
For these reasons, Siemens does not recommend the need for periodic verification of analog
caibration more often than once every ten years if the system design can accommodate a 0.1% drift
from original calibration.
This recommendation is based on the assumption that specified limits for the
modules have not been exceeded.
Calibration-related error messages and/or known overstress conditions being applied to analog I/O points
could indicate the need for verification before the end of a ten year period.
Table 2–1 Field Wiring and Terminal ID
CHANNEL
CONFIGURATION
CONNECTION TYPE
(see note)
TERMINAL
IDENTIFICATION
Analog Input Current · +24 Vdc to 2-Wire Transmitter
· Signal Common (-) or return PWR
COM
Analog Input Voltage · (+) Input from 4-Wire Transmitter
or (+) 1-5 Vdc voltage input
· Signal Common (-) or return VIN
COM
Analog Output · +24 Vdc to I/P or Valve Positioner
· Signal common (-) or return PWR
COM
Discrete Input Current · +24 Vdc to field contacts
· Signal common or return PWR
COM
Discrete Input Voltage · +24 Vdc to field contacts
· Signal common or return VIN
COM
Discrete Output · +24 Vdc to Solenoid or Relay
· Signal common (-) or return PWR
COM
Frequency Input Current* · (+) frequency input (current)
· Signal Common (-) or return PWR
COM
Frequency Input Voltage* · (+) frequency input (voltage)
· Signal Common (-) or return VIN
COM
Totalizer Input Voltage · (+) Voltage Pulses
· Signal Common (-) or return VIN
COM
Totalizer Input Current · (+) Current Pulses
· Signal Common (-) or return PWR
COM
All I/O cable shield SHLD