Siemens 505-2557 Centigrade or, Degrees Fahrenheit, Alarm Setpoints

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Additional Information about Each Function (continued)

Degrees

In advanced mode the selection of degrees C or F is controlled by the

Centigrade or

information stored and transferred to the module at WY72. The default

Degrees Fahrenheit

parameters are all zeroes which will cause the SIMATIC 505±2557 module

 

to return the value in degrees Centigrade x10. To select degrees F for the

 

module write a value of FFFF Hex to WY72 and use the documented

 

transfer procedure setting the data identification bits Y17, Y18 and Y19 to

 

1, 0, 0, (Refer to section 3.7).

 

To verify the Fahrenheit/Centigrade settings, the module reports back its

 

F/C status in WX57. The least significant bit (LSB) of WX57, corresponds to

 

channel one, while the most significant bit (MSB) corresponds to channel

 

16. A status bit of ª1º indicates the channel is reporting in degrees F.

 

A status bit of ª0º indicates the channel is reporting in degrees C.

Scaling

Numerical Range All numbers used for scaling are expressed as signed

 

integers.

 

The numerical range for scaling is ± 32767. If a value of ±32768 is loaded

 

into the module, then the value will be adjusted in the module to ±32767.

 

Arithmetic Overflow Scaling operations may result in arithmetic

 

overflow. Errors of this kind for each channel may be detected with the

 

WX54 arithmetic overflow bits.

 

Overflow conditions can occur during normalization of the input value. If

 

the input word reaches + 32767 or ±32767 before the ADC (analog-to-digital

 

converter) saturates, then an overrange condition occurs and the overrange

 

bit for that channel is set.

 

In a scaling operation, if the result of scaling forces the value to the PLC to

 

exceed 32767, the overrange bit for that channel is set.

 

During an overflow condition, the value to the controller defaults to ± 32767

 

and there is no rollover of data. That is, the data does not return to zero and

 

beyond.

Alarm Setpoints

Numerical Range All numbers used for alarm setpoints are expressed as

 

signed integers. The numerical range for scaling is ±32767. If a value of

 

±32768 is loaded into the module, then the value in the module is adjusted

 

to ±32767.

3-20 Advanced Function Programming

SIMATIC 505±2557 Installation and Operation Guide

Page 49 Page 51
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Page 49 Page 51
Contents Simatic Copyright 1998 by Siemens Energy & Automation, Inc Manual Publication History List of Effective Pages Contents Iv Contents List of Figures List of Tables Preface Community CE Agency ApprovalsEuropean ApprovalDescription 100 Ohm, 10 Ohm, 120 Ohm RTDs, or Millivolt InputsOperating Modes Word Input to the PLC from the Module RTD Input to Digital Conversion Scale UnitsOut-of-Range Input SignalsEffect Effect of Voltage Input 10 Ohm Copper Resolution Input ResolutionSelecting 2 and 3 Wire or 4 Wire Operation Installing and Configuring the ModuleCalculating the I/O Base Power Budget Installing and Configuring the Module Configuring Millivolt Input Temperature orSelecting Fahrenheit Selecting DegreesCelsius or Selecting DataConfiguration Jumper Locations Base InsertingModule Into Wiring the Input Connectors Copper Wire Table at 25 Degrees CelsiusPress In Wiring Connector Wiring Diagram for 2, 3, or 4 Wire RTD Wiring Diagram for Millivolt Measurements Cable Grounding Example I/O Configuration Chart Advanced Function Programming Overview Advanced Software FunctionsIntroduction AdvancedJumper Setting the ModuleConfiguration Memory LoggingController I/O Input Registers Internal Register StructuresInput and Output Register Offsets Input Channel DataInput Flag Bits Peak/Valley Hold Input WordsOutput Data Registers AveragingInputs Function Enable BitsControl Registers Discrete Handshake Inputs Outputs Data Identification BitsLoading Data into the Simatic 505±2557 Module Data Loading ProcessSample Low and High Alarm Setpoints Identifying the Data Being Transferred 11 Enabling the Functions Loaded Loading Programs into the I/O Module 13 Startup Relay Ladder Logic Page Timing Considerations When UsingTiming Overhead for Functions Enabled Timing ConstraintsDefault Function Values for Simatic 505±2557 Default ValuesDefault Function Values Additional Information about Each FunctionCentigrade or Alarm SetpointsDegrees Degrees FahrenheitDigital Filtering Hold AveragingPeak and Valley Hold Reset Flag BitsFunction PrecedenceTroubleshooting 10 Troubleshooting Flow Diagram Symptom Probable Cause Corrective ActionI/O Register Quick Reference 17 I/O Register Quick ReferenceOr K Memory Configuration Tables Page Addressing Worksheet Items Unique to the Simatic 505±2557 Module 18 Open RTD Status BitsTroubleshooting Specifications Table B-1 SpecificationsSpecifications subject to change without notice Jumper Settings Log Sheet Customer Response Business Reply Mail
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