Series 942
Contents
1. R RAX 20 RESU 18 REX 20 RH 20 RL 20 RS 422A 3 4 RS 423A 3 5 RTD 20 S SIL 20 SP1 20 Space 11 Starting Communications in ANSI X3 28 Protocol 15 Start of Text STX 12 Stopping Communications in ANSI X3 28 Protocol 16 T TAG 21 WwW Wiring Data Communications 4 6 X XON XOFF Command Example Fig 6 13 Command Example Fig 7 14 Protocol 3 Protocol for RS 423A 12 How to Use Data Communications How to Use Data Communications WATLOW Series 942 27 Series 942 Data Communications User s Manual Watlow Controls 1241 Bundy Blvd Winona MN 55987 Phone 507 454 5300 Fax 507 452 45072. Figures OONODOOBRWDND O Tables OONDOOABRWND ltem RS 422 Interface Wiring RS 423 Interface Wiring EIA 485 Interface Wiring RS 422 RS 423 Switch Selection General Message Syntax Example XON XOFF Command Example XON XOFF Command Example ANSI X3 28 Command Example ANSI X3 28 2 Command Example Data Logging Interface Wiring Data Logging Printout Example ltem ASCII Character Set ASCII Control Characters Partial Set Address to ASCII Conversion 2 Command Data and Responses Command and Command Data 2 MTR Command Response Data 2 STP Command Response Data STP Command Data Printer Troubleshooting How to Use Data Communications How to Use Data Communications with the Watlow Series 942 This manual is a supplement to the Series 942 User s Manual It is for users with the data communications option Use in conjunction with the Series 942 User s Manual This is expert user level material and requires previous experience with data communications Two Serial Hardware Interfaces and Two Software Protocols Depending on your units model number you may have one of two hardware interfaces 1 RS 422A for a multidrop or multiple device network up to ten devices total with 4000 ft network length limit or RS 423A RS 232C compatible for one on one communication on a 50 ft network with a 942 and a host com puter 945A XXXX B000 They are user selectable via in
3. This command asks the 942 for the type of unit and the level of software The model number will appear as 1 character The syntax of the function is as follows lt Space gt MDL This function will return the following information 942 lt Model numbers lt Space gt lt Software revision level gt 2 MTR Command The MTR command monitors the current RUNning step The syntax for this command is 2 lt Space gt MTR There are no arguments to the command The command will return the following data lt Current Step gt lt Space gt lt Current Step Type gt lt Space gt Data 4 lt Space gt Data 5 Data n Table 6 below shows how to interpret the response syntax Note that each argument is an ASCII decimal number representing a specific value for each parameter listed in the table A response would be lt 11 gt lt space gt lt 1 gt lt space gt lt 375 gt lt space gt lt 2 gt lt space gt lt 30 gt lt space gt lt 0 gt lt space gt lt 1 gt lt space gt lt 1 gt This tells you that the current step is 11 a Set Point step the SP is 375 Step time is 2 30 00 Events 1 and 2 Ent1 Ent2 are ON PtYP tl Step Type Set Point Set Point Soak Jumploop End Step lt Step gt lt Step gt lt Step gt lt Step gt lt Step gt Table 6 Type Code 1 1 2 3 0 2 MTR Command Data 2 lt SP gt lt SP gt lt HOUr gt lt JS gt lt End gt Response Data Data 3 lt rAtE gt lt HOUR gt lt min gt lt JC gt oe Data 4
4. lt Ent1 gt lt MIN gt lt SEC gt se als Data 5 lt Ent2 gt lt SEC gt lt Ent1 gt Data 6 lt Ent1 gt lt Ent2 gt lt Ent2 gt How to Use Data Communications WATLOW Series 942 21 Commands STP Command The STP command reads a given step in the Series 942 program space 24 steps total The syntax for this command is 2 lt Space gt STP lt Space gt lt Siep gt The command will return the following information lt Step gt lt Space gt lt Step Type gt lt Space gt Data 2 lt Space gt Data 3 Data n Table 7 below shows how to interpret the response syntax Note that each argument is an ASCII decimal number representing a specific value for each parameter listed in the table A response for Step 8 would be lt 8 gt lt Space gt lt 1 gt lt Space gt lt 235 gt lt space gt lt 1 gt lt space gt lt 20 gt lt space gt lt 15 gt lt space gt lt 1 gt lt space gt lt 0 gt This tells you that Step 8 is a Set Point step SP is 235 Step time is 1 20 15 Ent1 is ON and Ent2 is OFF PtYP rAtE PtYP tl Step Type Set Point Set Point Jumploop 1 j 2 ee onan lt SP gt lt SP gt lt HOUr gt Response Data lt rAtE gt lt HOUr gt lt min gt lt gt Non literal lt Enti gt lt min gt lt SEC gt Description lt Ent2 gt lt SEC gt lt Ent1 gt lt Ent1 gt lt Ent2 gt lt Ent2 gt HOLD Command This command causes the 942
5. program to HOLD If the program is already HOLDing an error will occur The syntax for this command not including protocol characters is lt Space gt HOLD lt Space gt 1 Check the HOLD status with MODE RESU Command This command causes a Series 942 program to RESUME If the program is already RUNning an error will occur The syntax for this command not including protocol characters is lt Space gt RESU lt Space gt 1 Check the RUN status with MODE 22 WATLOW Series 942 How to Use Data Communications STRT Command Commands This command causes the 942 program to start If the program is already RUNning an error will occur The syntax for this command not including protocol characters is lt Space gt STRT lt Space gt lt Step gt Check the RUN HOLD status with the MODE command STP Command NOTE ee eee ee ee ee OO TO You may write to a The STP command is used to program a given step in your profile Re Series 942 step with member that total profilespace is 24 steps You can use the STP command the STP Command only in the HOLD mode only when the unit is in the HOLD mode The syntax for this command not including protocol characters is lt Space gt STP lt space gt lt Step gt lt space gt lt Step Type Code gt lt space gt lt Data 5 gt lt space gt lt Data 6 gt lt space gt lt Data 10 gt Table 8 below shows how to interpret the syntax Note that ea
6. protocol To change the position of a switch remove the power from the Series 942 and turn the front panel locking screw 90 counterclockwise To remove the control chassis grip the front panel bezel and pull it straight out from the control case Set both switches the same C1 towards you for RS 423 or C2 away from you for RS 422 then return the control chassis to the case Be sure it is oriented correctly Press firmly but gently to seat the chassis Secure the front panel locking screw and reapply power Network Connections You can connect a data communication equipped Series 942 to any computer with an RS 422A or RS 423A RS 232C compatible or EIA 485 serial inter face The serial interface is the key The IBM PC with an RS 232C serial output card for instance will talk to a single RS 423A equipped Series 942 For a multiple 942 network with the same PC you ll need an RS 232 to RS 422 converter to act as a bus or multiple connection point A Watlow recommends the Burr Brown LDM 422 for that purpose The address is Burr Brown Inc 1141 West Grant Rd Suite 131 Tucson AZ 85705 Phone 602 624 2434 Fax 602 623 8965 B For ElA 485 we recommend the Black Box LD485A _ Their address is Black Box Corporation Mayview Road at Park Drive Box 12800 Pittsburgh PA 15241 Phone 412 746 5530 How to Use Data Communications WATLOW Series 942 7 Comm Software Connecting the Control and the Computer Remove p
7. 9 Example Format For your benefit we re presenting message response examples with syntax required for Series 942 communication Information bracketed by lt gt indicates a description rather than literal characters We show each ASCII character that you must transmit to the Series 942 including space between the charac ters A space is itself an ASCII character hex 20 For clarity we also represent each ASCII character as a hexadecimal pair The pairs are spread apart on the page for easy reading However electronic devices see the hex pairs all together in strings with no spaces in between For instance from the example just below you want to set the Alarm 1 Low A1LO parameter to 500 Notice the syntax just below which uses the command lt Space gt A1LO lt Space gt 500 lt Space gt A Figure 5 ASCII i L Series 942 Characters Oopa General Message Syntax Example 0 0 HEX ial 20 5 D0 WV Value 3D 20 41 31 4C 4F How to Use Data Communications WATLOW Series 942 11 XON XOFF 12 WATLOW Series 942 To send the message on Page 11 Figure 5 you key the ASCII characters into your computer or write them into your program The computer in turn will send a string similar to the one at the bottom of the example 3D2041314C4F20353030 Notice that we haven t mentioned protocol here or any characters added to this syntax by a protocol With XON XOFF the message above can be transmitted
8. S 423A RS 423A Interface Pinouts RS 232C Compatible 942A XXXX B000 The RS 423A communications uses a three wire full duplex system There is a separate line for transmitting a line for receiving data between the computer and the Series 942 and a line for signal common With RS 423A you can have only one Series 942 control connected to a single computer This diagram is a typical wiring example The connections on the host com puter may vary depending on models Refer to your computer user s manual for more information Host Computer rear view Figure 2 RS 423A Interface Pin Designations connector viewed from wire side RTS Request To Send CTS Clear To Send DSR Data Set Ready R and RLSD together and CTS together puter s user manual DTR Data Terminal Ready Jumper to Signal Common Signal Common Series 942 a D NOTE The Electronic Industry Association EIA RS 423A standard recom mends a maximum 50 foot total point to point distance Ay NOTE DB 9 Could be used for DB 25 depending on serial port connector How to Use Data Communications WATLOW Series 942 5 EIA 485 EIA 485 Interface Pinouts 942A XXXX D000 The ElA 485 communications uses a two wire half duplex system There are only two lines both lines used for transmitting and receiving Only one device the computer or the control can be speaking at a time There is a 5 millisec ond delay
9. Series 942 How To Use Data Communications with the Watlow Series 942 TOTAL CUSTOMER SATISFACTION oog O LOW Watlow Controls 1241 Bundy Blvd P O Box 5580 Winona MN 55987 5580 Phone 507 454 5300 Fax 507 452 4507 W942 XDCN Rev T00 10 00 August 1995 Made in the U S A Supersedes Ok Printed on Recycled Paper W942 SA20 9312 Page akRWwWw ltem Data Communications and the Series 942 Hardware Interfaces Protocols Communications Wiring RS 422A Interface Pinouts RS 423A Interface Pinouts RS 232C Compatible EIA 485 Interface Pinouts Setting Hardware Protocol Switches Network Connections Connecting the Control and Computer Communications Parameters ASCII and Series 942 Information Communication Software Series 942 General Message Syntax Message Syntax Data Rules Command List Example Format XON XOFF Protocol for RS 423A Start and Stop Communicating with the Series 942 and XON XOFF XON XOFF Command Example XON XOFF Command Example ANSI X3 28 Protocol for RS 422 amp EIA 485 Device Address Starting Communications in ANSI X3 28 Stopping Communications in ANSI X3 28 ANSI X3 28 Command Example ANSI X3 28 2 Command Example 2 Command Command 2 MDL Command 2 MTR Command 2 STP Command HOLD Command RESU Command STRT Command STP Command Data Logging NAKs and Error Codes User Responsibility Index WATLOW Series 942
10. TX gt The hex string will be 023F2041314C4F03 lt STX gt Optiona Carriage Space Return 1 ASCII Lo Figure 9 Characters lt sETX gt ANSI X3 28 2 Command Example HEX Value 02 3F 20 41 314C 4F 03 First response from the Series 942 lt ACK gt The lt ACK gt hex response string is 06 Your computer s confirming response lt EOT gt The lt EOT gt response hex string is 04 Second response from the Series 942 lt STX gt lt current A1LO value gt lt carriage return gt lt ETX gt The hex string is 023530302003 lt STX gt ASCII ae 0 Characters lt CR gt 0 HEX 2 i Your computer s next 7 Sponse lt ACK gt or lt NAK gt if the message needs to be repeated The hex string is 06 or 15 Final response from the Series 942 lt EOT gt The hex string is 04 How to Use Data Communications WATLOW Series 942 17 Commands 2 Command The command finds the specific value of a Series 942 parameter Data 1 Table 4 and 5 provide the complete list of parameters you may use plus responses You may use the command in either the RUN or HOLD modes Table 4 Information Commenis 2 Commands T C Only and Responses T C RTD whole process These commands T C RTD tenths process are READ ONLY R S B T C PROCESS Process value Between RL and RH SETPOINT Current Profile Set point Between RL and RH The Command reads a specific 0 100 The of jumploops r
11. The definition and number of arguments depends on the command itself See Table 5 Pages 19 21 In this example you want to change the Alarm 1 Low value to 500 Here the Command will do the job Command Syntax with ANSI X3 28 Protocol lt STX gt lt space gt Data 1 lt space gt Data 2 lt ETX gt With the Command Data 1 is the Series 942 parameter in this case Alarm 1 Low A1LO Data 2 is the value you want to set for that parameter in this example 500 Enter in ASCII lt STX gt lt space gt A1LO lt space gt 500 lt optional carriage return gt lt ETX gt The hex string is 023D2041314C4F 2035303003 lt STX gt lt Space gt A ASCII Character O space 0 0 lt ETX gt HEX 1 L Value 02 3D 2 41 31 4C 4F 2 2 4e wt Carriage Return How to Use Data Communications Response from the Series 942 lt ACK gt M ANSI X3 28 The hex response string is 06 e You ll find the the complete list of Command arguments parameters and value limits in Table 5 Pages 19 21 ANSI X3 28 Command Example You need to know the Alarm 1 Low value A1LO The uses a variation of the message syntax shown just below This syntax requires the protocol start of text and end of text characters Command syntax with ANSI X3 28 Protocol lt STX gt lt space gt lt Data 1 gt lt ETX gt Enter in ASCII lt STX gt lt space gt lt A1LO gt lt optional carriage return gt lt E
12. ace gt Data 3 Data N Command is a character set to which the Series 942 will respond The brackets lt gt enclose a non literal description Space is simply a delimiter an ASCII space character Hex 20 Data Fields are parameters and values specific to a command the number of possible data fields depends on the particular command you use Data 1 is here abbreviated Data 1 Data 2 is Data 2 and so on In the syntax explanations ahead we ll show you the specific arguments for each command It will speed the process if you remember this general syntax Data Rules Data fields are parameters and values specific to particular commands These rules govern their use Specific data for each command is listed later in this chapter Data will be ASCII 0 through 9 unless otherwise noted Data can go up to seven total characters including a minus sign A or sign if used must be first and it must have a decimal point if applicable Data can use leading zeros Up to 7 digits Data does use decimal points Data 1 portion of message can be up to four total characters How to Use Data Communications ASCII Command List These commands represented by their respective ASCII characters will enable you to program the Series 942 from your computer More detailed descriptions of the commands are on the pages noted Finds the value of a specific parameter p 18 Sets a specific parameter to a specific value p 1
13. aud rate is not set correctly The printer will The printer is off line Bring the printer on line not print The transmit and Make sure Terminal 20 and receive lines are 22 go to the printers appropriate reversed receive and transmit terminals NAKs and Error Codes When your message is not acknowledged NAK in RS 422A or EIA 485 with ANSI X3 28 Protocol you may clear ER2 code by reading it That is use Then try the message again you may have made a syntax error See the error code listing in Table 4 Page 18 With XON XOFF protocol and the RS 423A interface the 942 sends no feedback on commands Therefore you may want to query the status of ER 2 after each command you send All communications related error codes are ER2 error codes that is they are not considered cause for a shutdown of the 942 unit itself There is always a communications error code generated when a lt NAK gt character is sent under the ANSI X3 28 With XON XOFF flow control error codes may be generated but there will be no standard indication of this fact User Responsibility All of the previous commands are available on all models of the Series 942 that have communications capability It is the responsibility of the user to refrain from altering parameters which may not appear on the unit Example AXLO should not be set to 1 or 2 if the unit is not equipped with alarm outputs How to Use Data Communications WATLOW Se
14. ch data field is an ASCII decimal number representing a specific value for each parameter listed in the table A syntax example is Step 16 is a Set Point step with SP at 255 for 1 hour 36 minutes 58 seconds with EV1 ON and EV2 OFF would be lt space gt lt STP gt lt space gt lt 16 gt lt space gt lt 1 gt lt space gt lt 255 gt lt space gt lt 1 gt lt space gt lt 36 gt lt space gt lt 58 gt lt space gt lt 1 gt lt space gt lt 0 gt NOTE PtYP rAtE PtYP tl Step Type ce Set Point Set Point Jumploop Step lt Step gt lt Step gt lt Step gt lt Step gt lt Step gt Type Code 1 1 2 3 0 Data 5 lt SP gt lt SP gt lt HOUr gt lt JS gt lt End gt Data 6 lt rAtE gt lt HOUr gt lt Min gt lt JC gt Data 7 lt Enti gt lt Min gt lt SEC gt Data 8 lt Ent2 gt lt SEC gt lt Ent1 gt Table 8 p Data 9 lt Ent1 gt lt Ent2 gt Sed e it Data 10 lt Ent2 gt literal Description Data Logging The data logging feature is a convenient replacement for chart recorders Information is sent directly from the Series 942 to a serial printer or to a computer disk file No computer is needed Data logging provides a handy reference to review process performance The time intervals between each entry and the data printed are user selectable with the time display resetting each 24 hours The Prot parameter must be On and your control must have communications for t
15. e address identification number A Watlow RS 422A multidrop network can handle up to 10 devices with this protocol EIA 485 can handle up to 32 devices Set the address number with the Series 942 in the Addr parameter under the Setup menu ASCII Equivalent Table 3 0 9 0 9 Address to ASCII 10 31 A V Conversion Starting Communications in ANSI X3 28 Protocol Here s the syntax for starting communications with ANSI X3 28 Protocol The master device your computer must initiate the data link The example below uses the ASCII number 4 as a Series 942 device address Enter in ASCII using this syntax lt Address 4 gt lt ENQ gt ASCII 4 Characters lt ENQ gt HEX Value y4 6 Response from the 942 lt Address 4 gt lt Acknowledge ACK gt ASCII 4 Characters i lt ACK gt HEX Value A4 How to Use Data Communications WATLOW Series 942 15 ANSI X3 28 Figure 8 ANSI X3 28 Command Example 16 WATLOW Series 942 Stopping Communications in ANSI X3 28 Protocol The master device your computer must end communications with Device 4 by using Data Link Escape DLE and End of Transmission EOT characters Enter in ASCII lt DLE gt lt EOT gt ASCII Characters maids HEX Value 10 04 Response from the 942 None ANSI X3 28 Command Example The Command sets a specific 942 parameter to a specific value The general command syntax applies to all commands
16. eference Your computer hardware manual will provide more detailed serial port pin information Also refer to the noise prevention section in Appendix 2 of the Series 942 User s Manual In the often noisy environments of industrial locations it is important not to take noise isolation lightly How to Use Data Communications WATLOW Series 942 3 RS 422A RS 422A Interface Pinouts 942A XXXX B000 The RS 422A communications uses a four wire full duplex system There are two separate lines for transmitting and two lines for receiving data between the computer and the Series 942 With RS 422A you can have from one to ten Series 942 controls connected to a single computer This diagram is a typical wiring example The connections on the host com puter may vary depending on models Refer to your computer user s manual for more information Figure 1 RS 422A Interface Pin Designations Twisted Pair Wire lt gt Series 942 Optional Host Computer rear view Twisted Pair Wire D Ce Wan Ge R Je R gt Gy i Signal Common Series 942 Optional DB 9 female connector Com a NOTE The Electronic Industry Association EIA RS 422A standard recom mends a maximum 4000 ft total network distance Burr Brown Interface D See reference P 7A NOTE DB 25 Could be used for DB 9 depending on serial port connector 4 WATLOW Series 942 How to Use Data Communications R
17. emaining Run mode only value of the Series 942 parameter End Set Point of current step Run mode only Data 1 No error Multiple errors are possible Open sensor Reversed sensor Ambient sensor Configuration EE Checksum A D underflow A D overflow Not used No error Cleared when ER2 is read Transmit buffer overflow Only 1 ER2 response is valid Receive buffer overflow Framing error Overrun error Parity error Talking out of turn Invalid reply error Noise error Command not found Parameter not found Incomplete command line Invalid character Number of chars overflow Input out of limit Read only command Write allowed only Output 3 is not an event Output 4 is not an event Request to RUN invalid Request to HOLD invalid Command invalid in RUN mode Command invalid in RUN mode Infinite loop error _ ONOORWNMAO REBAYANMA0 See Page 21 Displays 942 X X software revision Run mode Multiple modes are possible Hold mode Configuration mode Calibration mode Alarm silence active OFF See Page 21 Monitors current step Run or hold mode See Page 22 Resume a profile Hold mode only 18 WATLOW Series 942 How to Use Data Communications Command Commands The command sets a specific Series 942 parameter Data 1 to a specific value Data 2 when the unit is in the HOLD mode Use Tables 4 and 5 to select parameters Data 1 in the lefthand column In Tab
18. har 00 o0 16 20 SP 30 0 1 2 3 4 5 6 Table 1 ASCII Character 7 Set 8 9 Hex Char p A a q B b r C Cc Ss D d t E e u F f v G g Ww H h xX i y J j Zz K k L l M m N n 5 O o ASCII Control Characters Partial Set Ctrl Key Definition Dec Equiv Equiv Ctrl E Enquiry 5 Ctrl F Acknowledge 6 Table 2 Ctrl U Neg Acknowledge 21 ASCII Control Ctrl B Start of Text 2 Characters Ctrl C End of Text 3 Partial Set Ctrl D End of Transmission 4 Ctrl P Data Link Escape 16 Ctrl M Carriage Return 13 Ctrl Q XON 17 Ctrl S XOFF 19 How to Use Data Communications WATLOW Series 942 9 10 WATLOW Series 942 Series 945 General Message Syntax As soon as you link the devices you ll be able to talk to the Series 942 using ASCII characters The Series 942 will respond to any operating or set up parameter plus some others The control will respond to either upper or lower case ASCII characters from your computer Both protocol interface combinations will respond to the general syntax providing the commands or queries are correctly transmitted However the ANSI X3 28 Protocol requires beginning and ending characters and the XON XOFF Protocol requires ending characters We ll look at those shortly Message Syntax Messages from your computer to the Series 942 must take this general form All commands do not require the full number of data fields Command lt Space gt Data 1 lt Space gt Data 2 lt Sp
19. he following parameters to appear Log Selects the data logging function for a printout of the data This parame ter will appear if your 942 has communications and Prot On How to Use Data Communications WATLOW Series 942 23 DEICH Moyereyiare Figure 10 Data Logging Interface Wiring Example Jumper DTR DSR and RLSD together Also jumper RTS and CTS together Refer to your printer s user manual Figure 11 Data Logging Printout Example 24 WATLOW Series 942 Int Selects the time interval for the logging function This parameter will appear if your Series 942 has communications Prot On and Log On The logging interval is in tenth of a minute increments tag Selects what variables are to be transmitted out during the data logging function This parameter will appear if your Series 942 has communications Prot On and Log On Any combination of process set point and auxiliaries may be tagged for logging Figure 10 shows a typical wiring example pig connections on the printer may vary depending on models DB 25 female connector located on back of printer viewed from wire side RTS Request To Send CTS Clear To Send DSR Data Set Ready Com DTR Data Terminal Ready RLSD Received Line Signal Detector T Jumper to Signal Common Signal Common 22 Series 945 1 Series 942 Example Log On Int 0 1 tag PSA P Process S Set Poi
20. he message syntax shown just below This protocol requires an ending carriage return character 2 Command syntax with XON XOFF Protocol lt space gt Data 1 lt CR gt Enter in ASCII lt space gt A1LO lt CR gt The hex string will be 3F2041314C4F0D Space Figure 7 1 XON XOFF 2 eae L Command Example araciers m O CR HEX Value 3F 2 41 31 4C 4F OD 14 The value of A1LO will be between rL Range Low and rH Range High say 500 Response from the Series 942 lt XOFF gt lt XON gt lt current value of A1LO gt lt CR gt The hex response string is 13113530300D lt XOFF gt lt XON gt ASCII 5 9 Characters 0 ii HEX Value 13 11 3 30 3 OD WATLOW Series 942 How to Use Data Communications ANSI X3 28 ANSI X3 28 Protocol for RS 422A and EIA 485 The ANSI X3 28 Protocol provides high quality communications by requiring a response to every message With a multiple device or multidrop network this protocol prevents confusion among the separate devices Furthermore if noise occurs somewhere in the system no parameter will change because noise can t comply with the protocol By placing messages inside a protocol envelope the messages are protected In the examples to come you ll see how this works The ANSI X3 28 Protocol requires STX characters at the beginning of a message and ETX characters at the end Device Address If you are using the ANSI X3 28 Protocol you must have a devic
21. le 5 the low and high limit or code values Data 2 are in the three center columns High Limit Process rL value rH value 0 to 999 NOTE An X means that it applies to either Function Alarm High X value Process RL value RH value 555 Deviation 999 Output 1 Auxiliary 3 or LAr EOWA Value Output 2 Auxiliary 4 0 No alarms occurring AL1H occurring AL1L occurring AL2H occurring AL2L occurring Writing a 0 will clear all alarms if the alarm condition no longer exists Table 5 and 2 Com 1 mands These are READ or WRITE Alarm 1 deviation Alarm 1 process commands See Table 4 for more Alarm 2 deviation Alarm 2 process w N O H Oj O No auto tuning Commands Slow response tuning Medium response tuning Fast response tuning When the 942 RTD 99 F 99 F 55 C 55 C 55 Units 55 Units Calibration offset input is 0 1 these parameters will have a decimal point to 0 1 Display C Display F the left of the least significant digit 1 60 Output X cycle time 0 99 F 0 55 C 0 Units 99 Units Dead band No decimal point 0 0 0 00 Output X derivative US prompts SI prompts Event Off Event On 0 99 F 0 55 C 0 Units 99 Units Guaranteed Soak Dev 1 F 99 F 1 C 55 C 1 Unit 99 Units Output X switching hys 1 1 UP DOWN key action 0 0 60 0 How to Use Data Communication
22. nd messages How to Use Data Communications XON XOFF XON XOFF Command Example The general command syntax is the one you ve already seen Each command uses a Slightly different variation of it depending on the number of arguments required for a message e You want to change the Alarm 1 Low A1LO value to 500 The Com mand will do the job The syntax with XON XOFF Protocol requires an ending Carriage Return lt CR gt Command Syntax with XON XOFF Protocol lt space gt Data 1 lt space gt Data 2 lt CR gt With the Command Data 1 is the Series 942 parameter in this case Alarm 1 Low A1LO Data 2 is the value you want to set for that parameter in this example 500 Enter in ASCII lt space gt A1LO lt space gt 500 lt CR gt The hex string will be 3D2041314C4F203530300D Figure 6 XON XOFF lt Space gt Command Example A ASCII ys Characters Dspace 5 0 0 lt CR gt HEX Value 3D 20 41 31 4C 4F 2 35 30 3 OD Response from the Series 942 It sends an XOFF when a carriage return is received and then an XON when the unit is done processing the command lt XOFF gt lt XON gt 13 11 The complete list of Command data parameters and value limits is in Table 5 Pages 19 21 How to Use Data Communications WATLOW Series 942 13 XON XOFF XON XOFF Command Example You want to know the Alarm 1 Low A1LO value The uses a variation of t
23. nts A Auxiliary Status Output 3 is configured as an alarm and Output 4 is configured as an event Parameters represented C1 SP1 A1LO AHI Ent2 TIME PROCESS SET 1 LOW 1 HIGH 1 Event 2 0 0 80 100 32 1382 1 0 1 81 100 32 1382 1 0 2 81 100 32 1382 1 0 3 82 100 32 1382 1 After each line the 942 emits a carriage return Your printer can be set up to handle line feeds The printer must supply a line feed LF following a carriage return CR Refer to your printer user s manual for more information A data header is printed when the logging function begins When you change the time interval Int any selected data tag or power is cycled the header will be printed again The time display wraps around to 0 0 every 24 hours How to Use Data Communications Data fields emitted are determined by the tag parameters and the control configuration As in the example above the tag parameter was set for PSA Process Set Points Auxiliary Status The 942 can also be connected to a computer with a serial port and terminal emulation software Logged data can be sent via the terminal program to a disk file Problem Action Printing all on The line feed Set the printer for a carriage the same line is missing return and line feed The printing is Data formats are 1 Match the Series 942 data Table 9 garbled not compatible format to the printers data Printer format using the Data prompt Troubleshooting 2 The B
24. ower from both the Series 942 and your computer before connecting them together This prevents noise or static interference from entering the data communication lines Assemble a cable and the appropriate wiring at your computer Refer to the wiring on Page 4 through 6 As soon as you connect the data communications line s you re ready to apply power to your system Series 942 Communication Parameters To communicate with the Series 942 match the serial port settings of your computer with the available settings in the 942 bAUd Rate 300 600 1200 2400 4800 9600 choose one dAtA 70 7 data bits and odd parity 7 E 7 data bits and even parity choose one 8 n 8 data bits and no parity Start bit 1 fixed Stop bit 1 fixed The bAUd and dAtA parameters are found under the Setup menu ASCII and Series 942 Information The next page shows you ASCII and control key equivalent tables Following that you will find a detailed explanation of the Series 942 syntax and command structure for each of the two protocols Communication Software Watlow has available a communications program for the Series 942 and is IBM PC or MS DOS compatible Ask your Watlow field sales representa tive for a copy of the Comm 4 program 8 WATLOW Series 942 How to Use Data Communications ASCII Character Set ASCII Char Dec Hex Char Dec Hex Char Dec Hex Char Dec Hex C
25. required for the Series 942 to go between transmission and receipt of data With EIA 485 you can have from one to thirty one Series 942 controls connected to a computer This diagram is a typical wiring example The connections on the host com puter may vary depending on models Refer to your computer user s manual for more information Figure 3 EIA 485 Interface Pin Designations T Re Twisted Pair Wire f 1 Signal Common Series 942 Optional Host Computer rear view T Re Twisted Pair Wire Signal Common Series 942 31 Optional DB 9 female connector viewed from wire side Ay NOTE The Electronic D Industry Association EIA 485 standard recommends a maximum 4000 ft total network distance Ay NOTE Black Box Interface See reference P 7B DB 25 Could be used for DB 9 depending on serial port connector 6 WATLOW Series 942 How to Use Data Communications Configuration ea Figure 4 TETE Hp ete RS 422A RS 423A C2 C2 f Down RS 422A Switch Selection LT D NOTE The Series 942 leaves the factory in RS 423A operation C1 How to Set the Hardware Protocol Switches for 942A XXXX B000 Units Only The RS 422 RS 423 switches are on the Communication Module Board A007 1830 Figure 4 shows the location of this board You can select both C1 switches for RS 423 or both C2 switches for RS 422 operation Both switches must be set the same for the desired
26. ries 942 25 Index A ALM 19 ALX 19 ANSI X3 28 Commana Fig 8 16 ANSI X3 28 Command Fig 9 17 ANSI X3 28 Protocol for RS 422A amp EIA 485 3 15 ASCII and Series 942 Information 8 ASCII Character Set Table 1 9 AXHI 19 AXLO 19 AUT 19 B Baud Rate 8 BTYP 18 Cc C1 18 CAL 19 Carriage Return 12 CF 19 Command 18 Command 19 Command Data and Table 5 19 Command List 11 Communications Software 8 Communications Switch Selection 7 Communications Wiring 3 Connecting the Control and the Computer 8 CTX 19 D Data Parameter 8 Data Link Escape DLE 16 Data Logging 23 Data Rules 10 DB 19 DEC 19 DEX 19 DFL 19 Device Address 15 E EIA 485 3 6 End of Text ETX 12 End of Transmission EOT 16 EJC 18 ENSP 18 ENTX 19 ERR 18 ER2 18 Example Format 11 F Flow Control 12 G GSD 19 H Hardware Interfaces amp Protocols 3 How to Use Data Comms with the Series 945 3 HYSX 19 26 WATLOW Series 942 l Identification Number 15 IN 20 INDC 19 INT 19 Interface Wiring RS 422A Fig 1 4 RS 423A Fig 2 5 EIA 485 Fig 3 6 ITX L LATX 20 LOC 20 LOG 20 M MDL 18 Message Syntax 10 MODE 18 MTR 18 Multidrop 3 N NAKs and Error Codes 25 Network connections 7 0 OFF 20 OUT 20 OTX 20 P PBX 20 POUT 20 PSTR 20 PTYP 20 Protocol XON XOFF 12 ANSI X3 28 15
27. s Time interval in minutes for logging 0 0 logging OFF WATLOW Series 942 19 Commands Low Limit High Limit Function 0 Table 5 Continued 12 OONDARWNM O ae ee ok won o J T C K T C T T C N T C PT2 T C C T C Not Used R T C S T C B T C RTD whole RTD tenths 0 5V 4 20MA Output X Integral O Latched alarms Non latched alarms Front panel lockout Logging OFF Logging ON See Page 21 Hold OFF Heat Cool output 1 amp 2 Cool Heat Heat no action Cool no action OT3 or 4 0 1 0 1 2 3 0 1 2 RW ma Alarm Event No action Process Retransmit Set Point Retransmit only applies to Ot4 999 F 555 C 999 Units Output X Proportional Band 3 Continue Hold Abort Reset Process Set Point O OIU N O Time Based Rate Based 0 00 9 99 Output X Rate 0 00 9 99 Output X Reset Min IN range Max IN range Range High Min IN range Max IN range Range Low 0 1 DIN JIS Alarm silence OFF Alarm silence ON 20 WATLOW Series 942 Set point How to Use Data Communications Commands Low Limit High Limit Function 0 7 NO loggin 7 al Table 5 S Continued SA ee NOTE oon P Process PS S Set Point PSA A Auxiliary Status no logging MDL Command
28. ternal switches See Page 7 2 EIA 485 945A XXXX DO000 also for a multidrop network up to 32 addresses total and with a 4000 ft network length limit There are two protocols available to you Depending on the type of network you need you must use the correct combination of interface and protocol We use ANSI X3 28 Protocol based on ANSI X3 28 1976 Subcategories 2 2 and A3 with the RS 422A and EIA 485 interface to run a multiple device network We also use XON XOFF Protocol a simpler protocol to run a two device network with an RS 423A interface XON XOFF will also work with the RS 422A and EIA 485 interface but the network is limited to two devices one computer or printer and a Series 942 XON XOFF Protocol requires no responses to messages like the ANSI X3 28 Protocol does Likewise ANSI X3 28 Protocol which provides a response to every message will work with the RS 423 interface But again you are limited to one Series 942 and a host computer or printer To select which protocol you are going to use go into the Setup menu and use the MODE key to advance to the Prot parameter Select either FULL for ANSI X3 28 2 2 A 3 or On for XON XOFF If you are using ANSI X3 28 Protocol choose an address number for the control under the Addr parameter following the Prot parameter This parame ter will only appear if Prot FULL Communications Wiring To connect your Series 942 to a computer use the next three pages as a r
29. with only an additional Carriage Return lt CR gt hex OD character at the end However the ANSI X3 28 Protocol requires an envelope of Start of Text lt STX gt hex 02 and End of Text lt ETX gt hex 03 characters around the information you see above You ll learn how to do that in the pages ahead XON XOFF Protocol for RS 423A XON XOFF flow conirol Protocol allows a communicating device either a 942 or the host to suspend transmission of all messages from the other device and then to continue transmission when it s again ready The device that needs to suspend transmission sends the XOFF character hex 13 to stop the other device s transmitter and XON hex 11 to restart it Note that technically any character will restart the transmitter but only the XON character is not a part of any regular message that may be transferring Messages transmit according to the syntax described in the XON XOFF formats which follow for each command The XON XOFF Protocol requires a Carriage Return character hex OD at the end of every message How To Start and Stop Communicating with the Series 942 and XON XOFF Starting communications with XON XOFF Protocol is simple You just config ure your computer to agree with the Series 942 communication parameters and open its serial communication port in software Then begin to talk by transmitting a message to the Series 942 You stop communicating with XON XOFF Protocol simply by ceasing to se
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