1771-6.5.17, Real Time Clock Module User Manual
Contents
1. T 17902 2 1 Chapter 2 Module Preparation and Installation Pushbutton Switches Two pushbutton switches labeled FUNCTION and DISPLAY are near the center of the front panel They set time and calendar functions The DISPLAY pushbutton switch changes the display of time and calendar information These switches are described in sections titled Setting Time and Calendar from the Front Panel and Displaying Time and Calendar from the Front Panel Display The LCD shows calendar time and diagnostic information You can display calendar and time information in any one of the following formats Figure 2 2 month with day of the month year with day of the week running time in minutes and seconds running time in hours and minutes The display of calendar and time information is covered in section titled Displaying Time and Calendar from the Front Panel Figure 2 2 Display Formats Calendar Functions Running Time Functions 701 05 37 July 1 Minutes Seconds s 1983 Friday Hours Minutes Colon Blinks 11217 2 2 Chapter 2 Module Preparation and Installation Display of Diagnostics The module displays fault and alarm diagnostics A battery low condition is indicated by the non blinking display of a single dot beneath the colon in the center of the display Figure 2 3 When the dot is first displayed 24 hours of battery operation remain Figure 2 3 Bat2. Allen Bradley Real Time Clock Module User Cat No 1771 DC M U a Table of Contents Introduction 1 1 GONG vs EA dA RR Eeidibesxdujedxc 1 1 Module Features 1 1 Applications 0 0 RII 1 2 Module Preparation and Installation 2 1 General z ye xaxa de doce eed RERUM AE 2 1 Panel Switches and Display 2 1 Reset Switch and Programming Plug 2 4 Battery Installation 2 5 Power Requirements 2 6 Chassis Location and Keying 2 6 Specifications 2 x es dixe T 2 7 Operation and Programming 3 1 General u a aie SOR eee DOOR ee eed e Rc d 31 Setting Time and Calendar from the Front Panel 3 1 Displaying Time and Calendar from the Front Panel 3 4 Block Transfer 3 4 General Module Features Introduction The Real Time Clock Module cat no 1771 DC lets you or the PC processor read or set real time and date information Current time and date information is block transferred to and from the PC processor data table for control and reporting purposes The clock modul
3. Programming and Operations Manual of your processor for additional information on these instructions Assume that the module is located in rack 1 module group 2 slot 0 3 7 Chapter 3 Operation and Programming PLC 2 Family The control byte and status byte corresponding to the module s address in the output and input image tables at word addresses 0124 and 1124 lower bytes respectively in this example The addresses of the enable bit and done bit for the block transfer read instruction are 012 07 and 112 07 respectively The addresses of the enable bit and done bit for the block transfer write instruction are 012 06 and 112 06 respectively The following addresses are also used in the example Figure 3 1 data address 050 module address 120 file words 1503 160 read file words 2503 2603 write When rung is true the enable bit 012 17 is set The data from the module is transferred into PC processor data table words 150 through 160 After the nine words of data are transferred to the PC processor done bit 112 07 is set When rung 2 is true the enable bit 012 06 is set Data to be transferred to the module is stored in the PC processor data table words 250 through 260 After the nine words of data are transferred to the module done bit 112 06 is set Figure 3 1 Block Transfer PLC 2 Family 1 BLOCK XFER READ DATA ADDR 050 MODULE ADDR 120 BLOCK LENGTH FILE 09 150 160 2 BLOCK XFE
4. 1 through 7 for day of the week the initial display for each function and an example setting for each function Once you have set the clock and calendar you can change any of the settings independently 3 1 Chapter 3 Operation and Programming 1 Start the function selecting and setting procedure by pressing the FUNCTION pushbutton until the day of the week display is obtained Al appears in the right most position on the display If another initial display should appear Table 3 A use only the FUNCTION pushbutton switch to advance through the remaining functions until the day of the week display appears Each time you press the FUNCTION pushbutton switch hold it for a second or two until the display advances to the next function Table 3 A Calendar and Time Functions Initial Example Range Display Example Setting Display Day of the Week Tuesday day 2 Year 00 99 DO 1984 B4 Month 1 12 1 June 6th month 6 Days of the Month 1 31 01 13th day 1 2 Hours 0 23 0 3 00 15 00 hours 15 Minutes 0 59 0 0 45 minutes 45 Seconds 0 59 0 0 27 seconds 227 Press FUNCTION display set time in hrs min the 1 5 45 colon is not blinking Press DISPLAY a displays date for several 613 seconds b displays running time the 15 45 colon is blinking The module clock starts when the DISPLAY pushbutton Switch is pressed 2 Enter the setting that you want by pressi
5. LOW DATA FD010 0000 15 LENGTH 09 CNTL CNTL 002 0000 R 13 gsi BTW CNTL 2 BLOCK XFER WRITE e RACK 012 CNTL GROUP 2 DN MODULE 0 LOW DATA FD011 0000 05 LENGTH 09 CNTL CNTL 002 0000 ER N 03 11257 3 9 Chapter 3 Operation and Programming 3 10 Programming Considerations Additional programming rungs should be added at your discretion Data from the module should be stored temporarily in a buffer file until the block transfer done bit is set indicating a valid transfer Program a boundary word after the last block transfer data address to prevent the PC processor from searching further in the accumulated value area for block transfer data addresses PLC 2 Family Program a watchdog timer and an indicating device to detect and signal the possible loss of communication with block transfer modules Block Transfer Timing Only one read or write block transfer can occur at a time When the PC processor is reading clock calendar and diagnostic data another block transfer is inhibited for 1 6ms until the time changes and the module s buffer memory is updated When the PC processor is writing new clock and calendar settings to the module subsequent block transfers are inhibited for 2 0ms until the new calendar and clock values are set The module time of 2 0ms maximum for a block transfer is shorter than the PC processor scan time Therefore the module is ready whenever it receives a requ
6. words transferred system layout for a PLC 3 controller and whether the PLC 2 family system contains local or remote I O Remote I O generally takes longer than local I O 3 11 A Accuracy See Specifications 2 7 Applications 1 2 Battery Installation 2 5 Specifications 2 7 Battery Low Indication 2 3 Block Transfer Programming 3 4 Timing 3 10 Buffer Memory 2 1 D Data Organization 3 5 Diagnostic Display 2 3 Display Formats 2 2 F Features 1 1 Functions Displaying from Front Panel 3 4 Setting from Front Panel 3 1 Setting to a Standard 3 4 K Keying 2 6 Index L Location in Chassis 2 6 P PC Processor Compatibility 1 1 Power Failure Indication 2 3 Power Requirements 2 6 Programming Block Transfer 3 4 Considerations 3 10 PLC2 Family 3 8 Family 3 9 Programming Plug 2 5 Pushbuttom Switches 2 2 R Rate Calculations 3 10 Reset Procedure 2 4 Reset Switch 2 4 S Securing the Settings 2 5 Specifications 2 7 Starting the Clock 3 3 Status Word 3 6 N Rockwell Automation Allen Bradley a Rockwell Automation Business has been helping its customers improve pro ductivity and quality for more than 90 years We design manufacture and support a broad range Allen Bradley of automation products worldwide They include logic processors power and motion control devices operator interfaces sensors and a variety of
7. R WRITE DATA ADDR 050 MODULE ADDR 120 BLOCK LENGTH 09 FILE 250 260 11220 3 8 Chapter 3 Operation and Programming PLC 3 Family The PLC 3 block transfer control file is in binary file 2 words 0 through 9 in this example Addresses of the control and status bits for the block transfer read instruction are FB002 0000 12 CNTL 12 for the enable bit and FB002 0000 15 CNTL 15 for the done bit Addresses of the control and status bits for the block transfer write instruction are FB002 0000 02 CNTL 02 for the enable bit and FB002 0000 05 CNTL 05 for the done bit Store block transfer read and write data in any two available decimal files designated by the appropriate section file number and starting word address such as FD010 0000 for read data and FD011 0000 for write data Figure 3 2 When rung 1 is true the enable bit CNTL 12 is set The data from the module is transferred into the PC processor data table in decimal file 10 words 0 through 8 After the nine words of data are transferred to the PC processor the done bit CNTL 15 is set When rung 2 is true the enable bit CNTL 02 is set Data to be transferred to the module is stored in decimal file 11 words 0 through 8 After the nine words of data are transferred to the module done bit CNTL 05 is set Figure 3 2 Block Transfer PLC 3 Family e BTR CNTL 1 M BLOCK XFER READ S E RACK 012 CNTL GROUP 2 DN MODULE 0
8. The wait bit will not be affected when changing the display of time or calendar from the front panel in steps 6 and 7 Bit 02 Name Invalid Value Description Set if a write block transfer contains a time or calendar value out of range If this happens the module will substitute the lowest displayed value for the out of range value Reset after a valid value is transferred in a subsequent write block transfer Bit 01 Name Communication Error Description Set when the module detects a PC communication fault during a write block transfer If this happens the clock module ignores the write block transfer and continues running with the previous data Reset by a subsequent write block transfer after proper communication is restored You should program a rung to examine this bit so that corrective action can be taken when a communication error occurs Bit 00 Name Valid Time Description Set when the clock module is running Reset when the wait bit is set or when the module stops as a result of a total power failure Sample Programs The format for programming block transfer depends on your PC processor If you are using a controller with a 3 position keyswitch Mini PLC 2 or PLC 2 20 controller use multiple get instructions If you are using a controller with a 4 position keyswitch Mini PLC 2 15 PLC 2 30 or a PLC 3 family controller use block format instructions The examples that follow use block format instructions Refer to the
9. e can be used with any of the following Allen Bradley PLC Processors that have block transfer capability and use the 1771 I O structure You can set or read the time and date through the front panel pushbutton switches and 4 digit liquid crystal display LCD Figure 1 1 You can program the PC processor to set or read time and calendar information automatically Also you can disable the time setting function to guard against unauthorized changes to an installed clock module Figure 1 1 Real Time Clock Module A it i Liquid Crystal Display Pushbutton FUNCTION 7 Switches 17901 Chapter 1 Introduction Applications Time and calendar functions are displayed as numbers For example Tuesday is designated by the module as the second day of the week It is displayed as a 2 The year 1984 is displayed as 84 The hour is displayed in military 24 hour format 3 00 pm 15 00 hours The clock module corrects for leap year The clock module displays the time and date formatted by day of the week year month day of the month hours minutes and seconds The clock module also measures time in milliseconds The module maintains quartz crystal accuracy of 60 seconds per month and timer accuracy of 0 25ms 1 25ms non cumulative over the normal operating temperature of 0 C to 60 C It uses a standard 9V alkaline battery for backup and reports self diagnostic informat
10. est to transfer data The clock module continuously stores time and calendar data in its buffer memory The moment it receives a request for a block transfer from the PC processor it latches the data in memory The data transferred to the PC processor is the data that the module latched when it received the block transfer request The clock module can be used as a millisecond timer allowing the PC processor to perform rate calculations When you use the clock module as a millisecond timer you can achieve accurate differential times by starting and stopping the clock in the same scans that the PC processor reads respectively the initial and final measured values This is done by enabling the timer with a write block transfer in the same scan that the PC processor reads the initial measured value and reading the timer s accumulated value with a read block transfer in the same scan that the PC processor reads the final measured value Locate the clock module in a slot adjacent to the I O module from which the measured values are read The differential accuracy is not affected by block transfer delays when operating in a local I O system Chapter 3 Operation and Programming The time required for a block transfer depends on factors independent of the clock module The delay before the next transfer depends typically on the processor scan time the number of block transfer instructions enabled simultaneously in the same scan the number of
11. ill cease and the data will be lost Under normal operation the clock module draws all of its power 350mA from the I O chassis backplane During a power outage the backup battery powers only the module s clock Place the single slot clock module in any bulletin 1771 I O chassis I O module slot The clock module is not keyed Other bulletin 1771 I O modules can be inadvertently placed in the slot reserved for the clock module However the clock module cannot be placed in a keyed I O slot Specifications Chapter 2 Module Preparation and Installation Accuracy e Total variation with time over the operating range of the module 0 to 60 C 60 seconds per month e Timing accuracy independent of transfers 0 25ms and 1 25ms Module Current Requirement e 350 max 5V DC from the backplane e 5 0mA max from backup battery during a power failure Backup Battery e Voltage 9V DC e Alkaline such as Duracell 1604A Eveready 522 or equivalent e Life One year standby when module is powered by the backplane up to 100 hours during a power failure including 24 hours from battery low indication until the clock ceases Module Location e Any bulletin 1771 I O chassis single I O slot location Ambient Temperature Rating e 00C to 60 C operational e 300 to 70 C storage Humidity Rating e 5to 85 without condensation Keying e None 2 7 General Setting Time and Calendar from the Front Panel Ope
12. ion whenever time and date information is read to the PC processor The accuracy and convenience of the clock module let you program many control and reporting applications such as energy management process synchronization time and event correlation calendar scheduling accurate millisecond timing accurate timing of power failures accurate rate calculations You can use the clock module with other bulletin 1771 I O modules in a variety of time dependent applications General Panel Switches and Display Module Preparation and Installation The clock module generates accurate calendar and time data performs continuous diagnostic tests has battery backup to retain its functions during a power failure responds to read and write block transfers from the PC processor and has two buffer memories each with a capacity of nine 16 bit words The buffer write only memory holds new calendar and time data received from the PC processor or entered from the front panel The buffer read only memory holds current calendar and time data that the module can transfer to the PC processor or display through the front panel LCD The front panel of the clock module contains two pushbutton switches and a 4 digit LCD Figure 2 1 Figure 2 1 Pushbutton Switches and Display pes REAL TIME CLOCK A eee i ER 14 06 N Of FUNCTION DISPLAY E
13. l three seconds then revert to running time in hours minutes However when the switch is released in either of the two running time displays the display remains until you change it 7 Select the next display by again pressing the DISPLAY pushbutton switch while the new display is still present within the three second interval for calendar displays In this manner you select in turn any one of the remaining three displays Once you release the DISPLAY pushbutton switch in a calendar display you allow the calendar display to revert to running time in hours minutes if you do not press the pushbutton switch again When you release the pushbutton switch in a running time display the running time display remains The clock module responds to read and write block transfer instructions The PC processor reads current time and calendar data from the clock module using read block transfers The PC processor writes calendar and clock settings to the clock module using write block transfers Nine words are transferred in either case Chapter 3 Operation and Programming WARNING Use only Allen Bradley authorized programming devices to program Allen Bradley programmable controllers Using unauthorized programming devices may result in unexpected operation possibly causing equipment damage and or injury to personnel The Allen Bradley Company will not be responsible or liable for any damages whether direct indirect or consequential a
14. lock and calendar cannot be set or if the module s clock will not start return the clock module to your nearest authorized field service or sales office for repair Reset Switch and Programming The lower rear section of the clock module contains a reset switch and a Plug programming plug Figure 2 4 Figure 2 4 Reset Switch and Programming Plug Reset Switch Programming Plug 17903 Reset Switch You can reset the module s clock and calendar functions by pressing and releasing the reset switch The LCD displays blinking eights indicating that the module s clock and calendar functions have ceased and are ready to be set 24 Battery Installation Chapter 2 Module Preparation and Installation You can access the reset switch only when the module with battery backup has been removed from the I O chassis Pressing the reset switch has the same effect as temporarily disconnecting the battery Programming Plug As a safeguard you can prevent unauthorized changes to the module s clock and calendar by means of a programming jumper plug The plug disables the FUNCTION pushbutton switch on the front panel but does not disable the DISPLAY pushbutton switch You insert the plug on two adjacent pins of a 3 pin assembly Figure 2 5 Place the plug on the upper two pins when setting the clock and calendar functions and when you do not want to disable the FUNCTION pushbutton switch Place the plug on the lower two pi
15. ng the DISPLAY pushbutton switch until the display counts up to your desired setting then release it 3 2 Chapter 3 Operation and Programming If you hold it too long and the count exceeds your setting continue pressing the DISPLAY pushbutton until the count recycles through the entire range 3 Continue selecting and setting the remaining calendar and time functions in this manner When you complete a setting press the FUNCTION pushbutton switch until the next initial display of a function appears Then press the DISPLAY pushbutton switch until the desired setting is reached Release it when the LCD displays your desired setting The last two steps of the procedure must be completed before the clock module begins timing 4 After selecting and setting the seconds function press the FUNCTION pushbutton switch The set time will be displayed in hours minutes but the colon will not blink because the module s clock is not running 5 Press the DISPLAY pushbutton switch to start the module s clock The month and day are displayed After several seconds the display automatically changes to the current time displayed in hours minutes The colon blinks to indicate that the module s clock is running Important The module s clock starts the instant that the DISPLAY pushbutton switch is pressed not released during step 5 Important You can change date settings and the hour setting without interrupting the module
16. ns to disable the FUNCTION pushbutton switch Figure 2 5 Programming Plug Positions Pin FIn Assembly Assembly E 4 Programming Plug 4 Programming Plug a Plug Position for Plug Position Disables Setting Functions FUNCTION Switch 11219 The battery compartment is under the clock module s lower front panel To open the compartment hook your finger over the upper edge of the hinged cover and pull the cover open Connect the battery to the 9Vdc battery connector When inserting the battery be sure that the connecting wires are not pinched by the hinged cover as you snap the cover into place Use a commercial 9Vdc alkaline battery such as Eveready 522 or Duracell 1064A for the backup battery Battery life is 100 hours total for intermittent or prolonged power outage Once the battery low 2 5 Chapter 2 Module Preparation and Installation Power Requirements Chassis Location and Keying 2 6 indication is displayed and if backplane power is not restored the battery must be changed within 24 hours or the module s clock and calendar functions will cease Do not change the battery during a power failure because clock and calendar data will be lost For dependable backup operation replace the battery annually or whenever the battery low indicator is illuminated or lights up CAUTION Do not replace the battery during a power outage or the clock and calendar functions w
17. ration and Programming Calendar and time functions can either be set and read manually or be set and read by the PC processor Upon initial installation of the module or upon recovery from a complete power failure not battery backup you must set the calendar and clock functions to start module operation This chapter describes how you set and read the calendar and time functions from the front panel and how you program block transfers so that calendar and time functions can be set and read by the PC processor The seven time and calendar functions are listed in the order that you set them day of the week year month day of the month hours minutes seconds Set the time and calendar functions initially when the clock module is installed or following a power failure if battery backup was inoperative The display will blink eights when power is applied The blinking eights display indicates that clock module functions are not operating but are waiting to be set You can set or reset the time and calendar functions conveniently using the front panel FUNCTION and DISPLAY pushbutton switches Briefly press the FUNCTION switch to advance the calendar set or time set function Press the DISPLAY switch until the display reaches the setting you want to enter The seven calendar and time functions are listed in the order that you initially set them Table 3 A The table includes the numerical range for each function such as
18. rising out of the use of such unauthorized programming devices Data Organization The same nine words are transferred in either a read or write operation Table 3 B During a write operation status word 0 and millisecond word 8 are transferred with zero value During a read operation the PC processor monitors the clock module s status as determined by status word 0 and reads the values of the remaining eight words including the millisecond word 8 When you program the block transfer instruction set the block length to the default value or to nine Any other block length can cause improper operation or prevent a block transfer Table 3 B Data Organization Data Format Word Name Range Bit Numbers 17 14 13 10 07 04 03 00 0 Status Word 0 1 0 0 00 BBBB 1 Day of Week 1 7 0 0 0 D3 2 B binary bit 3 D BCD digit 3 5 Chapter 3 Operation and Programming 3 6 Status Word Six bits in the status word are used to report module diagnostics The diagnostic word is included in each read block transfer of data to the PC processor Bit functions of the status word are described as follows Bit 17 06 Name None Description Not used set to zero Bit 05 Name Module Uninitialized Description Set to 1 if the clock module loses power without battery backup Total power failure is also indicated by flashing eights in the LCD Reset to 0 when the clock mod
19. s clock However the clock stops while you change the minute or second setting Refer to the description of the wait bit bit 03 in section titled Status Word for additional information on clock stoppage Important The time and calendar functions can also be set and the module started by a single write block transfer if you program the PC processor to perform this operation 3 3 Chapter 3 Operation and Programming Displaying Time and Calendar from the Front Panel Block Transfer Programming 3 4 Setting the Module to a Time Standard You can set the clock module to a time standard such as the one broadcast by radio station WWV 2 5 5 0 10 0 15 0 or 25 0MHz Complete function setting steps 1 through 4 to the next whole minute As the last step press the DISPLAY pushbutton switch the instant the time standard indicates the next whole minute Running time in hours minutes is displayed on the front panel LCD unless you select another calendar or time display The three other displays Figure 2 2 that you can select are month with day of the month year with day of the week running time in minutes seconds You can conveniently select the other running time and calendar displays with the front panel DISPLAY pushbutton switch 6 Press the DISPLAY pushbutton switch until the next display is presented The display remains as long as you depress the switch Once released calendar displays remain an additiona
20. software Rockwell is one of the worlds leading technology companies Worldwide representation MA Argentina Australia e Austria e Bahrain e Belgium Brazil e Bulgaria e Canada Chile China PRC Colombia Costa Rica Croatia e Cyprus e Czech Republic e Denmark Ecuador e Egypt El Salvador Finland France Germany Greece e Guatemala Honduras e Hong Kong Hungary Iceland e India Indonesia e Ireland e Israel Italy e Jamaica Japan e Jordan Korea Kuwait e Lebanon e Malaysia e Mexico e Netherlands New Zealand e Norway Pakistan Peru e Philippines e Poland e Portugal Puerto Rico Qatar e Romania Russia CIS e Saudi Arabia e Singapore Slovakia Slovenia e South Africa Republic e Spain e Sweden e Switzerland e Taiwan e Thailand Turkey United Arab Emirates e United Kingdom e United States Uruguay Venezuela e Yugoslavia Allen Bradley Headquarters 1201 South Second Street Milwaukee WI 53204 USA Tel 1 414 382 2000 Fax 1 414 382 4444 Publication 1771 6 5 17 February 1986 PN 955099 40 Supersedes 1771 824 September 1983 Copyright 1986 Allen Bradley Company Inc Printed in USA
21. tery Low Indicator Battery Low Indicator Does Not Blink 11218 The module indicates that power has been restored following a total power failure no battery backup by blinking the display of eights in its LCD The blinking eights display indicates that previous calendar and clock data have been lost that the calendar and clock functions have ceased and that the module s calendar and clock should be reset When a battery has been inserted in an unpowered clock module the blinking eights display indicates that the module s calendar and clock are ready to be set Battery backup allows 100 hours of clock operation during power failures or brownouts If the module detects an internal fault the module s clock will cease and a non blinking error number will appear in the right most digit space of the LCD Error numbers are used during factory diagnosis and repair In the event that an error number is displayed proceed as follows 1 Power down the I O chassis CAUTION Removing and inserting and I O module when the I O chassis is powered can result in possible damage to module circuitry 2 Remove the clock module 3 Press the reset switch see Reset Switch 2 3 Chapter 2 Module Preparation and Installation 4 Re install the module 5 Power up the I O chassis 6 Setthe clock and calendar and start the clock using the procedure in section titled Setting Time and Calendar from the Front Panel If the c
22. ule receives a write block transfer of time and or calendar data from the PC processor or when you press the FUNCTION pushbutton switch to set the time from the front panel You should program a rung to examine this bit to be sure that date and time data are valid before using the data Bit 04 Name Battery Low Description Set when the battery has approximately one day of battery life remaining when the battery is dead or when no battery is installed Reset when a new battery is installed You should program a rung to examine this bit to activate a visual and or audible signal when the bit goes high Bit 03 Name Wait Description Set while you are setting the time or calendar from the front panel Reset when the module s clock starts The clock module can be started manually from the front panel or by a write block transfer from the PC processor If the module s clock is running when you begin the time setting procedure for minutes or seconds the clock stops and the module sets the wait bit when you press the DISPLAY pushbutton step 2 If the module is powered but the clock is not running when you begin the time setting procedure for minutes or seconds the module sets the wait bit when you press the FUNCTION pushbutton switch step 1 Chapter 3 Operation and Programming The module can receive a write block transfer from the PC processor when the wait bit is set but the clock module will not start as a result
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