Inserting a Logic Gate. Entering the Operand and Testing. Inserting an OR Element. The On-Delay Timer Function. Programming the On-Delay Timer. Plain Speaking. Creating a New Project. Of Bits, Bytes and Words. Address Areas of the S The structure of the document. The chapter which you have. Power supply. Output side. Input side. The S Explorer can also be used to read or write user files to the memory cartridge. Page 56 which could be at any point in the scan cycle.
Interrupts are serviced by the S on a first-come-first-served basis within their respective priority assignments. See the Interrupt instructions in Chapter 6 for more information. This delay helps to filter noise on the input wiring that could cause inadvertent changes to the states of the inputs. Page 59 This ensures that a pulse which lasts for a short period of time is caught and held until the S reads the inputs.
You can individually enable the pulse catch operation for each of the local digital inputs. Page 60 S Programmable Controller System Manual Figure shows the basic operation of the S with and without pulse catch enabled. Page 62 The password is not case-sensitive. As shown in Table , the S provides four levels of access restriction. Each level allows certain functions to be accessible without a password.
For the four levels of access, entering the correct password provides access to the functions as noted below. Page 63 Warning Clearing the S memory causes the outputs to turn off or in the case of an analog output, to be frozen at a specific value. If the S is connected to equipment when you clear the memory, changes in the state of the outputs can be transmitted to the equipment. Page 64 The S provides integrated high-speed counter functions that count high speed external events without degrading the performance of the S Each counter has dedicated inputs for clocks, direction control, reset, and start, where these functions are supported.
Page Guidelines For Designing A Micro Plc System Identify the conditions that would assure the operation is not hazardous, and determine how to detect these conditions independently of the S This information should only be used for designing for the normal and expected abnormal operation, and should not be relied on for safety purposes.
The S executes these instructions sequentially, once per scan cycle. The main program is also referred to as OB1. Page 68 Because it is not possible to predict when the S might generate an interrupt, it is desirable to limit the number of variables that are used both by the interrupt routine and elsewhere in the program. This is because you are programming in the native language of the S, rather than in a graphical editor where some restrictions must be applied in order to draw the diagrams correctly.
As shown in Figure , this text-based concept is very similar to assembly language programming. Ladder programs allow the program to emulate the flow of electric current from a power source through a series of logical input conditions that in turn enable logical output conditions.
Power flow must be present at this input for the box instruction to be executed. The S does not read input data from or write output data to that module until the module configuration again matches the one obtained at startup. Page Fatal Errors SM4. Refer to Appendix C for the list of run-time programming problems. Program execution error information is stored in special memory SM bits.
You can make assignments to bytes, words, or double words of V memory. Comments are optional. Page Using Local Variables Using the Status Chart to Monitor Your Program A status chart allows you to monitor or modify the values of the process variables as your S runs the control program. You can track the status of program inputs, outputs, or variables by displaying the current values.
Page Conventions Used To Describe The Instructions S Instruction Set Chapter 6 Conventions Used to Describe the Instructions Figure shows a typical description for an instruction and points to the different areas used to describe the instruction and its operation.
Immediate Contacts An immediate contact does not rely on the S scan cycle to update; it updates immediately. When the Output instruction is executed, the S turns the output bit in the process-image register on or off. The result is loaded in the top of stack. After the ALD is executed, the stack depth is decreased by one. The Reset Dominant Bistable is a latch where the reset dominates. The Set Invalid dates, such as February 30, could be accepted. You should ensure that the date you enter is correct.
Page 96 case packers. The case packer packs eight tubs of butter into a single cardboard box. A diverter machine controls the flow of butter tubs to each of the case packers.
Four Ss control the case packers, and an S with a TD operator interface controls the diverter. Page 97 Figure shows the receive buffer VB and transmit buffer VB for accessing the data in station 2. The S uses a Network Read instruction to read the control and status information on a continuous basis from each of the case packers. Each time a case packer has packed cases, the diverter notes this and sends a message to clear the status word using a Network Write instruction.
Load the station address of case packer 1. Load a pointer to the data in the remote station. When you select Freeport mode, your program controls the operation of the communications port through the use of the receive interrupts, the transmit interrupts, the Transmit instruction, and the Receive instruction. Page Transmit buffer. Characters of the message If an interrupt routine is attached to the transmit complete event, the S Number of bytes to transmit byte field generates an interrupt interrupt event 9 for port 0 and interrupt event 26 for port The receive message function is automatically terminated in case of an overrun or a parity error.
If there is traffic present on the communications port from other devices when the Receive Page S Programmable Controller System Manual Idle line and start character: The Receive instruction can start a message with the combination of an idle line and a start character.
When the Receive instruction is executed, the receive message function searches for an idle line condition. After finding the idle line condition, the receive message function looks for the specified start character.
The message can be terminated on one or a combination of the following: End character detection: The end character is any character which is used to denote the end of the message. If receive status shows receive of end character, then attach a 10 ms timer to trigger a transmit and return. If the receive completed for any other reason, then start a new receive.
Page Compare Instructions However, both input values must be of the same data type. The size of the output buffer is always 8 bytes. The number of digits to the right of the decimal point in the output buffer is specified by the nnn field. Page The number or length of the resulting ASCII characters is the size of the output buffer and can be specified to a size ranging from 3 to 15 bytes or characters. The real-number format used by the S supports a maximum of 7 significant digits.
Attempting to display more than 7 significant digits produces a rounding error. Page Chapter 4. Attempting to display more than the 7 significant digits produces a rounding error.
Figure describes the format operand for the Real to String instruction. The length of the output string is specified by the ssss field. When the current value Cxx is greater than or equal to the preset value PV, the counter bit Cxx turns on.
When the current value CV is greater than or equal to the preset value, the counter output bit Q turns on. Programming Tips High-speed counters count high-speed events that cannot be controlled at S scan rates.
The maximum counting frequency of a high-speed counter depends upon your S CPU model. Refer to Appendix A for more information. Page S Instruction Set Chapter 6 Typically, a high-speed counter is used as the drive for a drum timer, where a shaft rotating at a constant speed is fitted with an incremental shaft encoder.
The shaft encoder provides a specified number of counts per revolution and a reset pulse that occurs once per revolution. The clock s and the reset pulse from the shaft encoder provide the inputs to the high-speed counter. Table shows the inputs used for the clock, direction control, reset, and start functions associated with the high-speed counters. The same input cannot be used for two different functions, but any input not being used by the present mode of its high-speed counter can be used for another purpose.
Current value loaded to 0, preset loaded to 4, counting direction set to up. Page S Programmable Controller System Manual When you use counting modes 6, 7, or 8, and rising edges on both the up clock and down clock inputs occur within 0. If this happens, the current value is unchanged and no change in counting direction is indicated. Page S Instruction Set Chapter 6 Current value loaded to 0, preset loaded to 9, initial counting direction set to up.
Counter enable bit set to enabled. Page Otherwise, the counter takes on the default configuration for the counter mode selected. Page HSC1 is used as the model counter in the following descriptions of the initialization and operation sequences. The initialization descriptions assume that the S has just been placed in RUN mode, and for that reason, the first scan memory bit is true.
If this is not the case, remember that the HDEF instruction can be executed only one time for each high-speed counter after entering RUN mode. Page In order to capture an external reset event, program an interrupt by attaching the external reset interrupt event event 15 to an interrupt routine.
Execute the global interrupt enable instruction ENI to enable interrupts. Exit the subroutine. Page event 15 to an interrupt routine. Initialization Modes 9, 10, or Page Load SMD48 double-word-sized value with the desired current value load with 0 to clear it. Enable the counter. Page Pulse Output Instruction PWM provides a continuous, variable duty cycle output with user control of the cycle time and the pulse width.
One generator is assigned to digital output point Q0. PTO can produce either a single train of pulses or multiple trains of pulses using a pulse profile. Page Chapter 6 Multiple-Segment Pipelining of PTO Pulses In multiple-segment pipelining, the S automatically reads the characteristics of each pulse train segment from a profile table located in V memory. Page S Programmable Controller System Manual There are two different ways to change the characteristics of a PWM waveform: Synchronous Update: If no time base changes are required, you can use a synchronous update.
With a synchronous update, the change in the waveform characteristics occurs on a cycle boundary, providing a smooth transition. Page S Instruction Set Chapter 6 In order to determine if the transitions between waveform segments are acceptable, you need to determine the cycle time of the last pulse in a segment. Unless the delta cycle time is 0, you must calculate the cycle time of the last pulse of a segment, because this value is not specified in the profile.
The input angle value is in radians. A measure of the error is given by the difference between the setpoint SP the desired operating point and the process variable PV the actual operating point. Page S Instruction Set Chapter 6 The S uses a modified form of the above simplified equation when calculating the loop output value.
This modified equation is: output proportional term integral term differential term where: is the calculated value of the loop output at sample time n Page S Instruction Set Chapter 6 Both the setpoint and the process variable are real world values whose magnitude, range, and engineering units could be different. Before these real world values can be operated upon by the PID instruction, the values must be converted to normalized, floating-point representations.
When you make the transition to RUN mode, interrupts are initially disabled. Page S Programmable Controller System Manual Operation of the Attach Interrupt and Detach Interrupt Instructions Before an interrupt routine can be invoked, an association must be established between the interrupt event and the program segment that you want to execute when the event occurs.
Use the Attach Interrupt instruction to associate an interrupt event specified by the interrupt event number and the program segment specified by an interrupt routine number. Page You can share data between the main program and one or more interrupt routines.
Because it is not possible to predict when the S might generate an interrupt, it is desirable to limit the number of variables that are used by both the interrupt routine and elsewhere in the program.
Page Communications Port Interrupts The serial communications port of the S can be controlled by your program. This mode of operating the communications port is called Freeport mode. In Freeport mode, your program defines the baud rate, bits per character, parity, and protocol.
The Receive and Transmit interrupts are available to facilitate your program-controlled communications. Page 1-ms timer update performed in the S Page S Programmable Controller System Manual Table shows all interrupt events, with their priority and assigned event number.
Globally enable interrupts. Page Program Control Instructions Expansion modules with discrete outputs also include a watchdog timer that turns off outputs if the module is not written by the S Use an immediate write to each expansion module with discrete outputs to keep the correct outputs on during extended Page If you use the Watchdog Reset instruction to allow the execution of a program that requires a long scan time, changing the mode switch to the STOP position causes the S to transition to STOP mode within 1.
Each For instruction requires a Next instruction. You can use the Jump instruction in the main program, in subroutines, or in interrupt routines. Whenever your application consists of a sequence of LSCR S0. Page S Instruction Set Chapter 6 Divergence Control In many applications, a single stream of sequential states must be split into two or more different streams.
When a control stream diverges into multiple streams, all outgoing streams must be activated simultaneously. This is shown in Figure Page S Instruction Set Chapter 6 In other situations, a control stream might be directed into one of several possible control streams, depending upon which transition condition comes true first.
Such a situation is depicted in Figure , which shows an equivalent SCR program. Page Shift And Rotate Instructions If the shift count is greater than or equal to the maximum for the operation 8 for a byte operation, 16 for a word operation, or 32 for a double-word operation , the S performs a modulo operation on the shift count to obtain a valid shift count before the rotation is executed.
This instruction provides an easy method for sequencing and controlling product flow or data. Use this instruction to shift the entire register one bit, once per scan. Get the length of the string that starts at VB I0. The search begins at the starting position specified by OUT which must be in range 1 through the string length.
The first value of the table is the maximum table length TL. The second value is the entry count EC , which specifies the number of entries in the table. N has a range of 1 to The first memory location of the table contains the length of the table in this case 20 entries. The second memory location shows the current number of table entries.
When the current value is equal to or greater than the preset time, the timer bit is on. For example: To ensure a minimum timed interval of at least ms for a ms timer, set the PV to Page S Instruction Set Chapter 6 To guarantee that the output of a self-resetting timer is turned on for one scan each time the timer reaches the preset value, use a normally closed contact instead of the timer bit as the enabling input to the timer.
You can use a Call Subroutine instruction with or without parameters. After the subroutine completes its execution, control returns to the instruction that follows the Call Subroutine. The parameters are defined in the local variable table of the subroutine. The parameters must have a symbol name maximum of 23 characters , a variable type, and a data type. Sixteen parameters can be passed to or from a subroutine. Page Communicating Over A Network Communicating over a Network The S is designed to solve your communications and networking needs by supporting not only the simplest of networks but also supporting more complex networks.
The S also provides tools that allow you to communicate with other devices, such as printers and weigh scales which use their own communications protocols. A selected network is referred to as an Interface. Masters A device that is a master on a network can initiate a request to another device on the network.
The system block of the S stores the baud rate and network address. After you select the parameters for the S, you must download the system block to the S You can also search the network at a specific baud rate or at all baud rates when looking for Ss.
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