SYSMAC CJ Series
The CJ1 family of programmable controllers offers a wide range of CPUs for simple and small-scale applications to high-power and robust machine control applications. The CJ1 series of CPUs can handle up to 2560 I/O points. The most important aspect of this series is that it offers a modular design, ensuring desired scalability and functionality per the operator’s requirements. All available I/O units are compatible with the entire range of CPU models, making it a suitable choice for customers who don't want to stock modules. The CJ1 family offers compactness, flexibility, and speed, which helps design machine control at any level. The CJ1 family is comprised of different models, including CJ1M, CJ1M (Pulse I/O), CJ1G, and CJ1H. The program capacity, processing speed, and the number of supported I/O increases from the CJ1M to CJ1H models.
The CJ1 CPU units offer various I/O bits, which range from 160 bits to 2560 bits. The base models do not support expansion racks, whereas the high-end models support up to three (3) expansion racks. The total data memory ranges from 32K words to 448K words, including both data memory (DM) and extended data memory (EM). The processing speed of LD instruction varies from 100 nanoseconds for the base models to 20 nanoseconds for the high-end models. For user memory extension, a memory card can be installed in all of the CPU models from the CJ1 family. The CJ1 series supports the Ladder Diagram (LD) programming language.
Input Units for the CJ1 Series
There are several input units for the CJ1 family that can be attached to a CPU to increase the functionality of the automation system as required.
- A high-speed unit is available with 16 inputs that operate on 24 volts DC. These high-speed units can read pulse widths as short as 0.05 milliseconds, which is impossible for normal I/Os.
- Temperature units enable the system to read temperatures from up to 6 sensors simultaneously with a resolution of 0.1 °C. The value from the sensor is stored in a 16-bit signed integer. It offers features like cold junction compensation, mains frequencies suppression, and broken or short-circuit alarms.
- Analog input units are available in 4-point or 8-point channels. These units convert data from analog sensors into binary data. The input signal can either be a voltage input signal (1 to 5 volts) or a current input signal (4 to 20 milliamperes). These units have built-in features like mean, offset gain, hold, and range functions. A resolution of 1/4000 to 1/8000 is achievable. The total conversion time for an 8-channel analog input unit is 2 milliseconds.
- Analog output units convert binary data into analog, which is given as an output signal to an actuator for machine control. It has built-in functions like offset gain, range selection, and output hold. A resolution from 1/4000 (default) up to 1/8000 (selectable) per channel can be achieved with a conversion time of 1 millisecond. The output signal can be generated in voltage form, from 1 volt to 5 volts, or in current form, from 4 milliamperes to 20 milliamperes.
- Analog I/O units are also available, with both analog input signals and analog output signals. These are available in 2- or 4-point models. A conversion time for a 6-channel unit is around 3 milliseconds with a resolution of 1/8000. In addition to the features available in analog input and output units, analog I/O units also offer a scaling function.
- Process input units are a type of unit that can measure temperatures directly from four (4) sensors. The input range of these units is shared between multiple inputs. A 2-input unit has a conversion time of 10 milliseconds, whereas a 4-input unit has a conversion time of 250 milliseconds.
- Temperature control units have both a temperature sensor and a control output built into a single unit. The temperature input sensors are either thermocouple or thermometer sensors. These units offer ON/OFF control or PID control. The PID control is 2-loop or 4-loop with an auto-tuning feature for tunning PID constants. The sampling period is 500 milliseconds.
- The position control unit provides a position control with high speed and precision for 1, 2, or 4 axes. These units support open-loop control and provide a pulse train at the output, which can be used as an input for servo or stepping motors. The speed, position, and acceleration parameters can be adjusted during execution.
- A high-speed multi-axis motion control unit is capable of controlling up to 32 physical axes. The speed, position, torque, and synchronization controls (gear and cam) all are supported by this unit.
- A high-speed multi-axis position controller is also available, which supports up to 16 axes and can control speed, torque, or position.
- A serial communication unit can be used to enhance the network and communication needs of the project. A single unit may contain two RS-232C or RS-422A/485 communication ports, or a combination of both.
- An RS-422A adapter is a converter unit that converts an RS-232 port to an RS-422A/485 port.
- RFID sensor units can read RFID tags at high speeds (160 bytes/scan) and transmit the data to the control unit for further processing. These units are available with one or two-point read-write heads.
- An Ethernet unit is also available separately, which can enhance data communication to even higher speeds and link a plant management system to the FA system.
- Some other units are available that can be used with the CJ1 series if required. These include a controller link unit, DeviceNet unit, CAN unit, and PROFIBUS-DP master/slave unit.
SYSMAC CJ2 Series
The SYSMAC CJ2 series is an improved version of OMRON's classic CJ1 series. The CJ2 series comes loaded with all the functions of its predecessor with enhanced performance and functionality. CJ2 programmable controllers have two performance classes, which include CJ2M and CJ2H based on the application requirements. The CJ2M is a base model for general automation and packaging needs, whereas the CJ2H is suited for more advanced automation requirements, like inspection through image processing and high-speed sorting. The CJ2M has a sub-category of simple (CJ2M-CPU1x) and standard (CJ2M-CPU3x) models. Similarly, the CJ2H has high-end (CJ2H-CPU6x) and flag-ship (CJ2H-CPU6x-EIP) models, with a major difference being the inclusion of an embedded Ethernet port.
Performance Comparison with CJ1-H
The CJ2 family offers much better performance than CJ1 program controllers. The cycle time has been significantly reduced. A performance test is conducted with a similar set of instructions for the CJ1-H and CJ2H. The results indicated a cycle time of 8.09 milliseconds for CJ1-H and 1.43 milliseconds for CJ2H. During the performance test, the common processing time was reduced from 300 microseconds to 100 microseconds, and instruction execution time was reduced from 20 nanoseconds to 16 nanoseconds for LD and 42 nanoseconds to 0.59 nanoseconds for SIN. Also, the refresh rate of the base I/O unit was reduced from 3 microseconds to 1.4 microseconds with immediate refreshing from 20 microseconds to 1 microsecond. The interrupt response was also found to be reduced from 200 microseconds to 100 microseconds for scheduled interrupts, and 30 microseconds to 17 microseconds for input interrupts.
Applications of CJ2 Controllers
Tension Control: The high-speed analog input and output enable fast responses, eliminating inconsistencies and reducing takt time.
Inline Measurement: Multiple high-speed analog inputs improve the accuracy of product detection on a conveyor.
High-speed Displacement Sensing: A high-speed communication unit gets input from displacement sensors and laser distance meters with short measurement cycles, and provides better control of inverters for motor control.
High-speed Scanning and Sorting: A high-speed serial communication unit provides quick data transfer of bar code labeled products on the conveyor to the CPU for a fast sorting response.
Synchronized Control: The position control unit ensures that information from AC servos' encoders to servo drivers is processed in minimal time.
Multi-axis Position Control: Using a position control unit with EtherCAT enables a minimal starting time of 0.4 milliseconds in applications like palletizing, which ultimately reduces takt time.
- The CPU variants of CJ2M have a program memory that ranges from 5K steps to 60K steps, whereas CJ2H CPU variants have a higher memory capacity ranging from 50K steps up to 400K steps. The data memory capacity is up to 160K words for CJ2M, and it ranges up to 832K words for CJ2H.
- The execution time is 40 nanoseconds for base instructions and 120 nanoseconds for special instructions in CJ2M. Similarly, the execution time is 16 nanoseconds for base instructions and 48 nanoseconds for special instructions in CJ2H.
- In CJ2 programmable controllers, there is an option to connect additional units with either a CPU rack or the expansion rack. The maximum number of units supported is 10. A single PLC (programmable logic controller) can simultaneously support up to 40 units, which means that up to three expansion racks can be added with a base CPU rack to extend the capabilities of the machine control based on the application requirements.
- The CJ2 family supports external memory options in addition to the built-in memory capacity. 128 MB, 256 MB, or 512 MB of memory can be added to the system externally. OMRON memory cards are the only memory cards recommended for memory expansion.
- CJ2 program controllers support all standard programming languages for PLCs, including ladder diagrams (LD), sequential function charts (SFC), structured text (ST), and instruction lists (IL).
- All CPU models of the CJ2 family come with a USB 2.0 port and a B-type connector with a baud rate of up to 12 Mbps and a maximum transmission distance of 5 meters.
- This family also supports serial communication. The CJ2H comes with RS-232C, whereas CJ2M has two variants in which one has RS-232C and the other has a serial option board where either RS-232C or RS-422A/485 can be mounted. The RS-232C has a transmission distance of up to 15 meters, whereas the RS-422A/485 has a transmission distance of 50 meters. The RS-422A/485 serial port also has an isolated-type variant that can transmit data to a larger distance of up to 500 meters.
- There are variants of CJ2M and CJ2H program controllers which are equipped with an Ethernet/IP port, in addition to a USB and serial port so that they can meet the demands of high-end applications. The baud rate for Ethernet communication is 100 Mbps, and data can be transmitted 100 meters without any trouble.
Pulse I/O Modules in CJ2M
The CJ2M model of the CJ2 family has an option to add two Pulse I/O modules. A CJ2M CPU with at least a unit version 2 is required to utilize these high-speed inputs and outputs. Each pulse I/O module adds 10 inputs and 6 outputs to the system. The I/Os can be used for general-purpose and origin search input or output. Additionally, inputs can be used as quick-response, interrupts, and high-speed counters, and the outputs as pulse or PWM outputs.
Functions of the Pulse I/O Module
Input interrupts: The pulse I/O module supports eight (8) quick-response inputs or interrupts. A pulse width of 30 microseconds can be used for quick-response inputs. An interrupt can be created on the rising edge of the input pulse, as well as on the falling edge.
High-speed counters: Up to four counter inputs can be used as pulse inputs through rotary encoders. Single-phase inputs can be counted at 100 kHz, while different phase inputs can be counted at 50 kHz. Motor rotations can be monitored using these high-speed counters.
Pulse outputs: Positioning control of up to four (4) axes can be achieved for stepping motors or servos. A short 1-millisecond pulse control cycle and a speedy startup of position control enhance the smoothness in movement and reduce machine takt time.