F3–08THM–n 8-Channel Thermocouple Input
Contents
1. conversion formula shown S high limit of the Engineering unit range NOTE The thermocouple versions automatically provide the correct temperature readings Scaling is not required The following example shows how you i A would use the analog data to represent Units 759g pressure PSI from O to 100 This example assumes the analog value is 1760 This should yield approximately 42 9 PSI aa 1760 Units 2096 100 Units 42 9 F3 08THM n 2 2 5 fe ce fe E o ta m lt O F3 08THM n 8 Channel Thermocouple Input The following instructions are required to scale the data We ll continue to use the 42 9 PSI example Once we ve explained how these instructions operate we ll show an example program This example assumes you have already read the analog data and stored the BCD equivalent in R400 and R401 Scale the data 114 115 116 DSTR F50 This instruction brings the analog value in BCD A into the accumulator VA M R400 Accumulator Aux Accumulator 1706o 0 0 0 0 R577 R576 The analog value is divided by the resolution of the DIV F74 module which is 4096 1760 4096 0 4296 K4096 Accumulator Aux Accumulator olopolo 4296 R577 R576 This instruction moves the two byte decimal peu FSO por2. MIL STD 810C 516 2 Noise Immunity NEMA ICS3 304 The F3 O08THM n Thermocouple Input appears as a 16 point module The module can be installed in any slot configured for 16 points See the DL305 User Manual for details on using 16 point modules in DL305 systems The limitation on the number of analog modules are e For local and expansion systems the available power budget and 16 point module usage are the limiting factors U IWHL80 4 0 0 z z oO 5 3 Q Q oO c pos o gt gt 9 4 F3 08THM n 8 Channel Thermocouple Input Setting the Module Jumpers Jumper Locations The module is set at the factory for C thermocouple readings If this is acceptable you do not have to change any of the jumpers The following diagram shows how the jumpers are set WARNING DO NOT change the calibration jumper settings If you think this jumper has been changed make sure it is NOT in the CAL position All calibration is performed at the factory Any changes to this may affect the module accuracy which could result in the risk of personal injury and or equipment damage Selecting F or C There is a jumper located on the bottom Operation of the board that selects between C and Measurement F temperature measurements This Selection jumper labeled F should be removed if ale you require C measurements a a F CNTS Remove this jumper for C operation Selecting 0 4
3. 0 0 014 2 9 eels F50 R577 R576 This instruction moves the two byte auxilliary accumulator for further operations Accumulator Aux Accumulator 0 4 2 9 0 4 2 9 DOUT F60 R577 R576 R450 wy This instruction stores the accumulator to R450 and R451 R450 and R451 now contains the PSI which implies 42 9 Accumulator Store in R451 amp R450 ol 4 2 0 4 21 9 9 Ry R451 R450 This example program shows how you can use the instructions to load these equation constants into data registers The example is written for channel 1 but you can easily use a similar approach to use different scales for all channels if required You may just use the appropriate constants in the instructions dedicated for each channel but this method allows easier modifications For example you could easily use an operator interface or a programming device to change the constants if they F3 08THM n 8 Channel Thermocouple Input are stored in Registers Load the constants 374 i DSTR F50 L K4096 DOUT F60 R430 DSTR F50 K1000 DOUT F60 R432 Read the data 374 A DSTR3 F53 1 1 R011 DOUT1 F61 R501 Store channel 1 es ane O TA A R430 DSTR F50 R576 MUL F73 R432 DSTR F50 R576 DOUT F60 R400 On the first scan these
4. fe So D F3 08THM n 8 Channel Thermocouple Input Multiplexing The example below shows how to read multiple channels on an F38 O8THM DL350 with a Thermocouple module in the X0 address slot of the D3 xx 1 base If any expansion D3 XX 1 Base bases are used in the system they must all be D3 xx 1 to be able to use this example Otherwise the conventional base addressing must be used Load the data _On SP1 i te LDF xo This loads the analog data from the module K12 BCD The BCD command converts the data to BCD format OUT The scaled value is stored in V1400 with an __ V1400 implied decimal Channel 1 Select Bit States X14 X15 X16 LD y J M M Vi V1400 This writes channel one data to V2000 when bits X14 X15 and X16 are as OUT shown V2000 Channel 2 Select Bit States X14 X15 X16 HA Lo V1400 This writes channel two data to V2001 when bits X14 X15 and X16 are as OUT shown V2001 2 Ccoa l5 Q Channel 3 Select Bit States fo BE X14 X15 X16 7s Vi F V njE VI IEE V1400 This writes channel three data to L V2002 when bits X14 X15 and X16 5 OUT are as shown cre V2002 Channel 4 Select Bit States X14 X15 X16 Pt iy LD ln ll V1400 This writes channel four data to V2003 when bits X14 X15 and X16 are as OUT shown V2003 F3 08THM
5. n 8 Channel Thermocouple Input Channel 5 Select Bit States X14 X15 X16 IA A__ LD Wi a V1400 This writes channel five data to V2004 when bits X14 X15 and X16 are as OUT shown V2004 Channel 6 Select Bit States X14 X15 X16 LD Ke dt K V1400 This writes channel six data to V2005 when bits X14 X15 and X16 are as OUT shown V2005 Channel 7 Select Bit States X14 X15 X16 A 4 LD VI V1400 This writes channel seven data to V2006 when bits X14 X15 and X16 OUT are as shown V2006 Channel 8 Select Bit States X14 X15 X16 lt LD ral V1400 This writes channel eight data to V2007 when bits X14 X15 and X16 S shown ca V2007 ts 2n 2a Usin i i 3 z g the Sign Bit oF Channel 1 Selected X17 is the sign bit when in module address 0 S Gs X14 X15 X16 X17 Co When the sign bit is on the sign control relay C0 D Pa f VA SET is set causing the temperature on channel one to be negative X14 X15 X16 X17 co la When the sign bit is not true the sign bit control bit J WAH RS i S is reset causing the temperature on channel one to be positive F3 08THM n 8 Channel Thermocouple Input Multiplexing The example below shows how to read multiple channels on an F3 O08THM DL350 with a Thermocouple module in the X20 X
6. stored load all twelve bits into the accumulator Math operations are performed in BCD This instruction converts the binary data to BCD You can omit this step if your application does not require the conversion The channel selection inputs are used to let the CPU know which channel has been loaded into the accumulator By using these inputs to control a DOUT instruction you can easily move the data to a storage register Notice the DOUT instruction stores the data in two bytes Two bytes are required for four digit BCD numbers F3 08THM n 8 Channel Thermocouple Input Using the Sign Bit By adding a couple of simple rungs you can easily monitor the temperature for positive vs negative readings For example you have to know whether the temperature is 100 F or 100 F Notice how we ve changed Channel 2 to control an output that denotes the sign of the temperature Read the data 374 DSTR3 F53 This rung loads the four data bits into the 1 R011 accumulator from Register 011 on every scan DOUT1 F61 Temporarily store the bits to Register 501 R501 DSTR1 F51 This rung loads the eight data bits into the R001 accumulator from Register 001 Temporarily store the bits to Register 500 Since SSTA F61 the most significant bits were loaded into 501 now R500 and R501 contain all twelve bits in order DSTR F50 Now that all the bits are stored load all twelve bits R500 i
7. 095 There is a jumper located on the bottom Operation of the board that allows you to disable the Measurement direct temperature conversion feature If Selection you install a jumper on the CNTS pin the temperature will be represented by a callie digital value between 0 and 4095 For a a example an E type thermocouple would have a value of 0 for 450 F and a value F CNTS of 4095 for 1832 F 7 NOTE If you are using the 1 50mV or the 2 100mV millivolt input versions you should make sure this jumper is installed Install this jumper to obtain digital values 0 4095 F3 08THM n 2 2 5 fe ca fe o Ta m lt O F3 08THM n 8 Channel Thermocouple Input Connecting the Field Wiring Wiring Guidelines Your company may have guidelines for wiring and cable installation If so you should check those before you begin the installation Here are some general things to consider e Use the shortest wiring route whenever possible e Use shielded wiring and ground the shield at the signal source Do not ground the shield at both the module and the source e Don t run the signal wiring next to large motors high current switches or transformers This may cause noise problems e Route the wiring through an approved cable housing to minimize the risk of accidental damage Check local and national codes to choose the correct method for your application User Power Supp
8. 16 X17 LD V2200 This writes channel four data to V3003 when bits X124 X125 and X126 are as shown OUT V3003 LD V2200 This writes channel five data to V3004 when bits X124 X125 and X126 are as shown OUT V3004 LD V2200 This writes channel six data to V3005 when bits X14 X15 and X16 are as shown OUT V3005 X17 is the sign bit when in module address 0 When the sign bit is on the sign control relay CO CO C Z V4 is set causing the temperature on channel one to be negative X14 X15 X16 X17 Co RSF When the sign bit is not true the sign bit control bit ye i Ne D is reset causing the temperature on channel one to be positive U IWHL80 4 A gt D E 3 fe fe fe a D F3 08THM n 8 Channel Thermocouple Input Scaling the Most applications usually require we AH L p i f Units A Input Data measurements in engineering units 4095 which provide more meaningful data sh tes a This is accomplished by using the H high limit of the engineering conversion formula shown unit range L low limit of the engineering You may have to make adjustments to unit range the formula depending on the scale you choose for the engineering units A Analog value 0 4095 For example if you wanted to measure pressure PSI from 0 0 to 99 9 then you would have to multiply the analog value by 10 in order to imply a de
9. 27 120 127 address of a DL305 conventional Conventional base The first six channels are shown DL305 Base Load the data _On SP1 LDF X120 This loads the upper byte of the analog data from the module K8 SHFL This shifts the to the left to make room for the K8 lower byte of data ORFS X20 This brings the lowewr byte of data from the K8 module into the accumulator ANDD This masks off the 12 analog data bits Kfff BCD The BCD command converts the data to BCD format OUT The channel data is stored in V2200 V2200 Channel 1 Select Bit States X124 X125 X126 LD This writes channel one data to V3000 1 when bits X124 X125 and X126 are Vi Vv v 2200 as shown OUT f Channel 2 Select Bit States V3000 c 2 eee ie 4 a on V2200 This writes channel two data to V3001 Te when bits X124 X125 and X126 are OUT as shown oOo V3001 oe Channel 3 Select Bit States 5 X124 X125 X126 LD y I 1 1 oe M Mao V2200 This writes channel three data to V3002 when bits X124 X125 and X126 are as shown OUT V3002 Channel 4 Select Bit States X124 X125 X126 F3 08THM n 8 Channel Thermocouple Input A Channel 5 Select Bit States X124 X125 X126 VHAN Channel 6 Select Bit States X124 X125 X126 Ema Channel 1 Negative Temp X14 X15 X
10. 7662 number of channels to scan Q 2 5 fe ca fe o Ta m lt O This loads an octal value for the first V memory location that will be LDA used to store the incoming data For example the O02000 entered 02000 here would designate the following addresses Ch1 V2000 Ch2 V2001 Ch3 V2002 Ch4 V2003 Ch5 V2004 Ch6 V2005 Ch7 V2006 Ch8 V2007 The octal address 02000 is stored here V7672 is assigned to slot Te 2 and acts as a pointer which means the CPU will use the octal value in this location to determine exactly where to store the incoming data F3 08THM n 8 Channel Thermocouple Input 9 17 The table shows the special V memory locations used with the DL350 Slot 0 zero is the module next to the CPU slot 1 is the module two places from the CPU and so on Remember the CPU only examines the pointer values at these locations after a mode transition The pointer method is supported on expansion bases up to a total of 8 slots away from the DL350 CPU The pointer method is not supported in slot 8 of a 10 slot base Analog Input Module Slot Dependent V memory Locations Slot 0 1 2 3 4 5 6 7 No of Channels V7660 V7661 V7662 V7663 V7664 V7665 V7666 V7667 Storage Pointer V7670 V7671 V7672 V7673 V7674 V7675 V7676 V7677 U IWHL80 4 D atc re
11. F3 08 THM n 8 Channel Thermocouple Input In This Chapter Introduction Module Specifications Setting the Module Switches Connecting the Field Wiring Module Operation Writing the Control Program 9 2 F3 08THM n 8 Channel Thermocouple Input F3 08THM n Q 2 5 fe ce fe E o ta m lt O Introduction Automatic Conversion Hardware Features Diagnostic Features The F3 08THM n Thermocouple Input Module provides eight differential thermocouple input channels 12 bit resolution The module automatically converts type E J K R S or T thermocouple signals into direct temperature readings No extra scaling or complex conversion is required You can select between F or C operation This module is also available in versions specially designed to convert millivolt signal levels into direct digital values 0 4095 Two versions are available one for 0 50mV and one for 0 1 00mV The F3 08THM n also features automatic cold junction compensation thermocouple linearization plus analog and digital filtering The temperature calculation and linerazation are based on data provided by the National Bureau of Standards Thermocouple burnout and other errors are automatically reported to the CPU For example if the thermocouple becomes disconnected then a value of 4095 is assigned to that channel F3 08THM n 8 Channel Thermocouple Input 9 3 Module Spec
12. at will be assigned to the module F3 08THM TC O 8pt 8pt 8pt 16pt 8ch 16pt 9 O Relay Output Output Input Analog Input 050 040 030 020 010 000 027 017 007 057 047 037 120 110 100 127 117 107 Within these two register locations the individual bits represent specific information about the analog signal 00 The next to last three bits of the upper Q Register indicate the active channel The R011 47 indicators automatically increment with MSB LSB aL each oT scan E 39 Active Channel 11111111 OT Scan Inputs Channel eae ee e N 000 1 a N 1 001 2 active channel 5 N 2 010 3 indicator inputs N 3 011 4 N 4 100 5 N 5 101 6 N 6 110 7 N 7 111 8 N 8 000 1 9 8 F3 08THM n 8 Channel Thermocouple Input F3 08THM n 2 2 3 fe ce fe E o ta lt O Temperature Sign Bit Analog Data Bits Temperature Input Resolution Millivolt Input Resolution The most significant bit is used to note the sign of the temperature If this bit is on then the temperature is negative If the bit is off then the temperature is positive The first twelve bits represent the temperature If you have selected the 0 4095 scale the following format is used Bit Value Bit Val
13. cimal place when you view the value with the programming software or a handheld programmer Notice how the calculations differ when you use the multiplier Here is how you would write the program to perform the engineering unit conversion This example assumes you have BCD data loaded into the appropriate V memory locations using instructions that apply for the model of CPU you are using NOTE This example uses SP1 which is always on You could also use an X C etc permissive contact SP1 When SP1 is on load channel 1 data to the accumulator LD k v3000 MUL Multiply the accumulator by 1000 to start the conversion K1000 DIV Divide the accumulator by 4095 K4095 OUT Store the result in V3010 V3010 F3 08THM n 2 2 3 fe ra fe E gt o ta lt O F3 08THM n 8 Channel Thermocouple Input 9 23 Temperature and Since the thermocouple devices are non linear it is much easier to rely on published Digital Value standards for conversion information The National Bureau of Standards publishes Conversions conversion tables that show how each temperature corresponds to an equivalent signal level Millivolt and Digital Sometimes it is helpful to be able to quickly convert between the signal levels and the Value Conversions digital values This is especially helpful during machine startup or troubleshooting The following table provides
14. er and store the information you re ready to write the control program F3 08THM n 8 Channel Thermocouple Input 9 9 Writing the Control Program DL330 DL340 Identifying the Since all channels are multiplexed into a single data word the control program must Data Locations be setup to determine which channel is being read Since the module provides input points to the CPU it is very easy to use the channel status bits to determine which channel is being monitored F3 08THM y y CI O 8pt 8pt 8pt 16pt 8ch 16pt 6 Relay Output Output Input Analog Input 050 040 030 020 010 000 z 027 017 007 057 047 037 120 110 100 127 117 107 lo O m R 002 R012 r R011 R 001 MSB LSB MSB LSB TRTA EEE ee 1111 1 0 0 1111 1 1 1 7654 0 7 0 temperature sign active channel indicator inputs i 00 F data bits Q 39 Automatic If you are using the temperature scale F or C then you do not have to perform any ro Temperature scaling Once you convert the binary temperature reading to a four digit BCD 34 Conversion number you have the temperature 9 z os 4 5 F3 08THM n 2 2 5 fe ca fe o Ta m lt O F3 08THM n 8 Channel Thermocouple Input The
15. first two instructions load the analog resolution constant of 4096 into R430 and R431 These two instructions load the high limit of the Engineering unit scale constant of 1000 into R432 and R433 Note if you have different scales for each channel you ll also have to enter the Engineering unit high limit for those as well This rung loads the four most significant data bits into the accumulator from Register 011 on every scan Temporarily store the bits to Register 501 The analog value is divided by the resolution of the module which is stored in R430 and R431 This instruction moves the decimal portion from the auxilliary accumulator into the regular accumulator for further operations The accumulator is multiplied by the scaling factor which is stored in R432 and R433 This instruction moves most significant digits now stored in the auxilliary accumulator into the regular accumulator for further operations The scaled value is stored in R400 and R401 for further use U IWHL80 4 0 0 z z io 5 3 Q Q oO c oO gt F3 08THM n 8 Channel Thermocouple Input Writing the Control Program DL350 Reading Values There are two methods of reading values for the DL350 Pointer Method e The pointer method all system bases must be D3 xx 1 bases to and Multiplexing support the pointer method e Multiplexing You must use the multiplexing method with remote I O modules the
16. following example shows a program designed to read any of the available channels of data into Register locations Once the data is in a Register you can perform math on the data compare the data against preset values etc Since the DL305 CPUs use 8 bit word instructions you have to move the data in pieces It s simple if you follow the example Read the data 374 DSTR3 F53 1 1 R011 DOUT1 F61 R501 DSTR1 F51 R001 DOUT1 F61 R500 DSTR F50 R500 BCD F86 Store channel 1 114 115 116 1 1 j 1 R400 Store channel 2 114 11 11 9 DOUT F60 R402 Store channel 3 114 11 11 7 DOUT F60 VA vA R404 Store channel 4 114 115 116 DOUT F60 A R406 Store channel 5 114 11 11 gt DOUT F60 Fiat R410 Store channel 6 11 11 1e 7 6 DOUT F60 Z R412 Store channel 7 114 115 116 DOUT F60 i R414 Store channel 8 114 115 116 DOUT F60 R416 This rung loads the four data bits into the accumulator from Register 011 on every scan Temporarily store the bits to Register 501 This rung loads the eight data bits into the accumulator from Register 001 Temporarily store the bits to Register 500 Since the most significant bits were loaded into 501 now R500 and R501 contain all twelve bits in order Now that all the bits are
17. formulas to make this conversion easier MV50 50D 4095 A gt D A 0 to 50 mV 4095 50 MV100 100D 4095 A D A 0 to 100 mV 4095 100 For example if you are using a 4095 2 100mV version and you have D 100 measured the signal as 30 mV you would use the following formula to D 4095 30 determine the digital value that should be stored in the register location that contains the data D 40 95 30 D 1229 U IWHL80 4 D am re fe So D
18. ifications Analog Input Configuration Requirements The following table provides the specifications for the F3 O8THM n Thermocouple Input Module from FACTS Engineering Review these specifications to make sure the module meets your application requirements Number of Channels 8 differential inputs Input Ranges Type E 270 1000 C 450 1832 F Type J 210 760 C 350 1390 F Type K 270 1370 C 450 2500 F Type R 0 1768 C 32 3214 F Type S 0 1768 C 32 3214 F Type T 270 400 C 450 752 F 1 0 50 mV 2 0 100 mV Resolution 12 bit 1 in 4096 Input Impedance 27KQ DC Absolute Maximum Ratings Fault protected input 130 Vrms or 100 VDC Cold Junction Compensation Automatic Conversion Time 15ms per channel minimum 1 channel per CPU scan Converter Type Successive Approximation 574 Linearity Error 1 count 0 03 of full scale maximum Maximum Inaccuracy at 77 F 25 C 0 35 of full scale Accuracy vs Temperature 57 ppm C maximum full scale Power Budget Requirement 50 mA 9 VDC 34 mA 24 VDC External Power Supply None required Operating Temperature 32 to 140 F 0 to 60 C Storage Temperature 4 to 158 F 20 to 70 C Relative Humidity 5 to 95 non condensing Environmental air No corrosive gases permitted Vibration MIL STD 810C 514 2 Shock
19. ke up to eight scans to get data for all channels Once all channels have been scanned the process starts over with channel 1 a Scan E 1 O Update Channel 1 gt Scan N Execute Application Program Channel 2 gt Scan N 1 Read the data I Channel 8 I Scan N 7 Store data Channel 1 i Scan N 8 D A Even though the channel updates to the CPU are synchronous with the CPU scan the module asynchronously monitors the thermocouple signal and converts the signal to a temperature or 12 bit binary representation This enables the module to continuously provide accurate measurements without slowing down the discrete control logic in the RLL program F3 08THM n 2 2 3 fe ra fe E gt o ta lt O 9 7 F3 08THM n 8 Channel Thermocouple Input Understanding the You may recall the F3 08THM n module appears to the CPU as a 16 point module I O Assignments Active Channel Indicator Inputs These 16 points provide e an indication of which channel is active e the digital representation of the temperature Since all I O points are automatically mapped into Register R memory it is very easy to determine the location of the data word th
20. ly The F3 08THM n receives all power from the base A separate power supply is not Requirements required Wiring Diagram Note 1 Terminate shields at the respective signal source Note 2 Leave unused channels open no connection Internal Module Wiring THERMOCOUPLE F3 08THM co A D See note c Cc 1 sarc ba 1 cH ak w LV 2 2 AN Examples of differential 2 Thermocouple wiring 2 A 3 oo lay aX 3 Th m 3 Q CH3 lt BO c gt 6 a0 L C 4 4 A 4 S Ea 4 3 I Analog 5 je sry Switch 45 9 5 C Gs c 4 6 7 P l EN 6 gt CH6 lt 6 AN 7 WY 7AA Examples of grounded 7 Thermocouple wiring 7 TV 8 2 8 CH8 lt A AN C Cc l prane l 9 6 F3 08THM n 8 Channel Thermocouple Input Module Operation Before you begin writing the control program it is important to take a few minutes to understand how the module processes and represents the analog signals Channel Scanning The F3 08THM n module supplies1 channel of data per each CPU scan Since Sequence there are eight channels it can ta
21. n extra decimal of precision Notice in the following example we ve added another digit to the scale Instead of a scale of 100 we re using 1000 which implies 100 0 for the PSI range This example assumes you have already read the analog data and stored the BCD equivalent in R400 and R401 Scale the data 114 115 116 This instruction brings the analog value in BCD WA WA DoT F50 into the accumulator V V V 00 Accumulator Aux Accumulator 11 71 61 0 0 0 01 0 R577 R576 DIV E74 The analog value is divided by the resolution of the KA096 module which is 4096 1760 4096 0 4296 Accumulator Aux Accumulator 0 0 0 0 4296 R577 R576 This instruction moves the two byte decimal R F50 portion into the accumulator for further operations Accumulator Aux Accumulator 429 6 4296 W R577 R576 MUL F73 The accumulator is multiplied by the scaling factor K1000 which is now 1000 1000 x 4296 4296000 The most significant digits are now stored in the auxilliary accumulator This is different from the way the Divide instruction operates Accumulator Aux Accumulator 6 0
22. nto the accumulator Math operations are performed in BCD This BCD F86 instruction converts the binary data to BCD You can omit this step if your application does not require the conversion Store channel 1 114 115 116 The channel selection inputs are used to let the 7 7 P DOUT F60 CPU know which channel has been loaded into the R400 accumulator By using these inputs to control a DOUT instruction you can easily move the data to Store channel 2 a storage register Notice the DOUT instruction 114 115 116 stores the data in two bytes Two bytes are DOUT F60 required for four digit BCD numbers Z R402 114 115 116 117 200 If 117 is on then the temperature on channel 2 is Va SET negative 114 115 116 117 200 If 117 is off then the temperature on channel 2 is PA JA RST positive Store channel 3 114 115 116 DOUT F60 V A Rio Store channel 4 114 115 116 R406 U IWHL80 4 0 0 z oO 5 3 Q Q je c pes oO gt 9 12 F3 08THM n 8 Channel Thermocouple Input Scaling the Input If you are using the 1 50mV or the A Data 2 100mV versions you may want to Units 759g scale the data to represent the measurements in engineering units Units value in Engineering Units which provide more meaningful data A Analoa value 0 4095 This is accomplished by using the J l
23. pointer method will not work You can use either method when using DL350 but for ease of programming it is strongly recommended that you use the pointer method Pointer Method The DL850 has special V memory locations assigned to each base slot that greatly simplifies the programming requirements These V memory locations allow you to e specify the data format e specify the number of channels to scan e specify the storage locations The example program shows how to setup these locations Place this rung anywhere in the ladder program or in the Initial Stage if you are using RLLPLYS instructions This is all that is required to read the data into V memory locations Once the data is in V memory you can perform math on the data compare the data against preset values and so forth V2000 is used in the example but you can use any user V memory location In this example the module is installed in slot 2 You should use the V memory locations for your module placement SPO LD or LD rl K 0800 a K 8800 Loads a constant that specifies the number of channels to scan and the data format The upper byte most significant nibble MSN selects the data format i e O BCD 8 Binary the LSN selects the number of channels i e 1 2 3 4 5 6 7 8 The binary format is used for displaying data on some operator interfaces F3 08THM n OUT Special V memory location assigned to slot 2 that contains the V
24. tion into the accumulator for further operations Accumulator Aux Accumulator 4219 429l 6 6 Ww R577 R576 MUL F73 The accumulator is then multiplied by the scaling K100 factor which is 100 100 x 4296 429600 Notice the most significant digits are now stored in the auxilliary accumulator This is different from the way the Divide instruction operates Accumulator Aux Accumulator 9 6 01 0 Oj 0 4 2 DSTR F50 R577 R576 R576 This instruction moves the two byte auxilliary accumulator for further operations Accumulator Aux Accumulator olol 4 0 0 4 2 2 DOUT F60 R577 R576 R450 W This instruction stores the accumulator to R450 and R451 R450 and R451 now contain the PSI which is 42 PSI Accumulator Store in R451 amp R450 olol 4 0 0 4 2 2 wy R451 R450 U IWHL80 4 A gt D E 3 fe fe fe a D F3 08THM n 2 2 5 fe ce fe E o ta m lt O F3 08THM n 8 Channel Thermocouple Input You probably noticed the previous example yielded 42 PSI when the real value should have been 42 9 PSI By changing the scaling value slightly we can imply a
25. ue 0 LSB 1 6 64 1 2 7 128 2 4 8 256 3 8 9 512 4 16 10 1024 5 32 11 2048 R011 MSB LSB s F O ona KR wor hp 1 own F temperature sign R011 R001 MSB LSB EATA MARTA 1111111 00000000 iriri AA 6543210 76543210 1 Fi _ data bits Typically the F3 O8THM n resolution enables you to detect a 1 C change in temperature The National Bureau of Standards publishes conversion tables that show how each temperature corresponds to an equivalent signal level Since the module has 12 bit resolution the analog signal is converted into 4096 pieces ranging from 0 4095 212 For example with a 2 100mV module a signal of 0 mV would be 0 and a signal of 100 mV would be 4095 This is equivalent to a a binary value of 0000 0000 0000 to 1111 1111 1111 or 000 to FFF hexadecimal The diagram shows how this relates to the example signal range Each piece can also be expressed in terms of the signal level by using the equation shown The following table shows the smallest signal levels that will result in a change in the data value for each signal range 0 100 mV Scale gt n H L Resolution 4095 H high limit of the signal range L low limit of the signal range 0 50 mV 50 mV 0 mV 12 2 uV 0 100 mV 100mA OMA 24 2 uV Now that you understand how the module and CPU work together to gath
Download Pdf Manuals
Related Search