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Sysmac CQM1 vs Sysmac CJ Series PLCs

PLCs are essential for designing and implementing control applications customized to meet customer needs. These PLCs are programmed through text-based or graphical instructions for specific industrial time-sensitive control applications ranging from simple fan control to complex control architectures.

When choosing suitable PLCs for your applications, Sysmac PLCs can come in handy as it has provided professionals with an integrated automation platform. Sysmac gives a complete control and management solution for automation plants. Machine Automation Controller is the core of this platform and simplifies problem architectures, reduces programming efforts, and increases productivity.

The Machine Automation Controller offers more than just programming – it comes integrated with all logic, motion, safety; robotics; information; visualization; networking, and more, enabling users to design an IDE environment explicitly made for themselves. This controller stands out even further because it contains embedded EtherCAT and EtherNet/IP, which are two significant features when needed without any latency or connectivity issues!

There are many different types of Sysmac series PLCs with varying features. This guide will provide an overview of the key differences between two kinds of Sysmac series PLCs: Sysmac CQM1 vs Sysmac CJ Series PLCs.


The CQM1-series Programmable Controllers are somewhat similar to the CJ-Series Programmable Controllers in terms of architecture. The CJ series offers fast speed, high capacity, and more functionality – but it does not come with an Inner Board or screw-mounting options, while the CQM1H comes with these features. The critical difference between both lies within customization, where the CJ series PLC supports fewer customized options. CQM1 PLCs provide customizable add-ons such as advanced functionalities, specialized I/O, and communications modules – ultimately providing some potential at least additional flexibilities to what it can offer on a larger scale.

These CJ-series PLCs function with a task-based programming system like their larger counterparts – providing instructions faster than ever before; I/O Memory where needed; usability throughout different tasks that need it; and Messaging capabilities. All these Units come together on the side of one big computer, which can be attached to a DIN track if need be. While most CQM1 CPUs have an RS-232C port used to communicate directly with another CQM1 Computer or another device connected through this port, none of them but the CPU11-E one has this port installed by default.

Sysmac CQM1 Supports all current and future input/output and specialized input/output devices, while CJ Series PLCs support DeviceNet open network and Protocol Macros To enable information sharing in machines, including Seamless Message Communications across Ethernet, Controller Link, and DeviceNet networks.


Processing for overhead, I/O refreshes, and peripheral servicing is faster on the CJ series. The CJ series provides considerable capabilities for high-value applications such as machine interfaces, communications, data processing, and so on owing to its up to 250k steps of program capacity, 256k words of DM Memory, and 2,560 I/O points.

The CQM1 series, on the other hand, offers a program capacity of up to 15.2k with an expansion of maximum I/O points of 512 points with 16 built-in DC inputs. DM memory ranges from 1k to 6k words depending on the model number.

I/O Expansion Units

In the CJ-series PLC, you can connect 1 to 10 input /output (I/O) control units to the single CPU rack and 3 more I/O expansion racks can be attached to the CPU.

However, CQM1 series PLCs are suitable for applications that need 0 to 11 I/O modules, as well as the use for expansion and control interfaces that allow for up to 16 I/O modules to be attached. 

Advance Features

The built-in inputs and outputs of the CPU Unit can be used for a wide range of tasks. When a crucial instruction is carried out during a PLC cycle, immediate I/O refreshing can be done on the I/O. 

The CJ-series only has four built-in input ports for CPU Units, whereas the CQM1 PLC series’ CPU unit has 16 input ports.

The SYSMAC CJ Series PLCs are equipped with enhanced essential performance and increased programmability. However, the additional features (i.e., other I/O units, several high-speed timers, and counters pre-installed) in SYSMAC CQM1 series PLCs make it more powerful and faster. 

The CJ series has a built-in serial port which can optionally include a serial option board. There is also a PLC replacement selector which can help find the suitable replacement unit for any machine one is currently running, as well as an adapter for reusing old I/O cables when upgrading one’s equipment. Robust networks make CQM1series rank higher of all PLCs – with an advanced instruction set including PID, Floating Point Math, Protocol Macro Instructions, and more.

Basic Programming Steps in CQM1 and CJ Series

Writing a program for both series involves the following fundamental programming steps:

  1. Design a table that lists all input/output devices, input/output locations, and the I-O bit assigned to each device.
  2. Identify the words that can be used as work bits and make an allocation table based on how they will be used.
  3. To illustrate the design, make a ladder diagram.
  4. Using Code Flow Notation, enter the program in mnemonic form into the central unit (through its programming terminal).
  5. After that, review your work for syntax mistakes and fix any that you find.
  6. Once it has been run (by being executed), make any necessary edits until you are satisfied with the outcomes. 


An excellent way to ensure a project gets completed efficiently is to divide it into tasks. This could be done when the work involves separate functions, control systems, or processes, allowing one programmer to focus on one particular task while others focus on another simultaneously. 

There are 32 cyclic tasks and 256 interrupt tasks in the CJ series. The four interrupts include power-off interrupts, scheduled interrupts, I/O interrupts – which come from input units or bus units – and external interrupts from output units connected by special cables. Programmers can combine standard programs, so they’re all part of just one complex program. 

However, the CQM1 series provides three types of interrupts:

  • Input Interrupts are used to handle input signals from an external device faster than the program can run. Input signals with pulse widths as short as 0.1 milliseconds may be used.
  • Scheduled Interrupts can be done using a high-speed interval timer.
  • High-Speed Counter Interrupts have been added (absolute encoder input for the CPU44-EV1), allowing users to combine this capability with pulse outputs for applications such as motor control.

Instructions for Ladder Diagrams

The CQM1 does not have an I/O table inside its CPU Unit, which is why it operates according to the specific Units configured within the PLC. When programming a ladder using the CQM1’s SYSMAC-CPT, inputs and outputs are shown by placing ‘I’ for input words or bits in the program and ‘Q’ for output words or bits. However, even though most features of this system can accommodate this change, printing still cannot because it has yet to be upgraded.

Inputting Ladder Diagrams can be achieved through different instruction commands in various CQM1 and CJ series models. Only IR 000 to IR 011 is allowed as input words for the CQM1 on the SYSMAC-CPT. For the CQM1-CPU4j-EV1 CPU Unit, one can input IR 012 to IR 015, and the program is appropriately executed even if those bits were not present; however, I or Q would not display indicating whether they were inputs or outputs.

However, CJ-series PLCs involve formatting files, deleting, copying, changing file names, creating new directories, and performing similar activities on a Memory Card, all available from the ladder program during PLC operation. This can be accomplished with protocol macros and text string instructions. The text string instructions make it simple to execute text processing from the ladder program. With the macro protocol function, these instructions reduce the time it takes to process messages going out and coming in.


The LSS is a programming and control package meant for C-series PLCs. Along with essential programming functions, the software offers advanced debugging, monitoring, and program management functionality. One such function is Force Set /Reset, which can force bits ON (force set) or OFF (force reset), useful when troubleshooting programs or checking wiring outputs in CQM1 series devices. CQM1 series PLCs include debugging, monitoring, and various program modes.

In the CJ series, (TRSM) Trace memory sampling is used as debugging instruction. This setting causes the status of a preselected bit or word to be sampled by the power supply controller without executing a specific operation. Only trigger lines are required rather than any additional configuration parameters; information about what was tested is saved as long as TRSM(045) remains active.

Conformance to EC Directives

The Sysmac CQM1 and CJ-series PLCs are EC Directive compliant. Install the PLC per the following conditions to ensure that the machine or device being used complies with EC directives:

  • The Sysmac CQM1 and CJ-series PLCs are required to be inserted in a control panel. 
  • For the power supplies attached to DC Power Supply Units, as well as I/O Units, there needs to be a firm layer of reinforced insulation or double insulation applied over them.
  • EC Directive-compliant CQM1 and CJ-series PLCs also meet the Common Emission Standard (EN50081-2) and (EN 61000-6-4), respectively.

Variations in Radiated Emission Characteristics are possible due to the design of the Control Panel interface in CJ-series, adjacent devices plugged into it, wiring, etc. When a CJ or CQM1 series PLC is installed into a machine, one must validate that the overall machine or equipment complies with EC Directives. Nevertheless, noise can be created by switching devices employing relay outputs, causing the entire system to fail to meet the requirement if this occurs. 

If the machine fails to operate, surge suppressors or other precautions must be implemented outside the CQM1 series PLC. There are common strategies for decreasing noise in both PLCs. Still, they may only sometimes work, so one must determine what works best in any specific scenario depending on how one’s system runs while still fulfilling all EU Regulations.

Pulse I/O Modules

In Sysmac CJ Series, an interface device called Pulse I/O Module is required to use the CJ2M with external devices. A maximum of two modules may be installed on either side of a CJ2M processor module. However, there are two dedicated ports in Sysmac CQM1 series PLC for high-speed Pulse Inputs and Outputs (CN1 and CN2), capable of pulsing at 10 Hz – 50kHz if necessary. These ports will provide smoother frequency changes in using a contact output. The Sysmac CQM1 series consists of results up to 1 kHz, which can be utilized when Output Unit contacts are activated. 

CJ-series PLCs pulse I/O modules are available in models CJ2M-MD211 (Sinking outputs) and CJ2M-MD212 (Sourcing outputs) for the 40-pin MIL connector pins found on these units. The CPU unit detects which modules have been inserted each time it powers up, so even if one swaps out module types during operation, there won’t be any problems. 

Normal I/O Modules

In Sysmac CJ series PLCs, the status of input signals for comparison standard inputs is read and stored in I/O memory during the I/O refresh period, just as they would be for an Input Unit. One can also set a programmed input’s response time to ON or OFF–a quick or slow signal will come from it, respectively. There is enough space for 20 inputs with allocated bits of CIO 2960 and CIO 2962 (bits 00-09).

In Sysmac CQM1 series PLCs, there are two types of I/O Units: Terminal Blocks and Connectors. Only CQM1-OD213 DC Input Units (32 points) and CQM1-OD213 Transistor Output Units (32 points) are Connector Type Units.

Convenient I/O Instructions are available in the Sysmac CQM1 Series – their single instructions can be used to either input or output data, simplifying programs.

  1. The TEN KEY INPUT instruction can read 8-digit binary data from a ten-key.
  2. The instruction HEXADECIMAL KEY INPUT may read 8-digit hexadecimal key input data from I/O Units.
  3. DIGITAL SWITCH can read binary data from digital switches with 4 or 8 digits.
  4. The 7-SEGMENT DISPLAY OUTPUT opcode may output binary data to 7-segment displays in 4 or 8 numbers.

The Sysmac CJ series has typical outputs used to output standard signals. These points refresh when the allocated bit (either ON or OFF) changes states. Output terminals exist at bits 00-05 of CIO 2961 and CIO 2963, and function assignments can be made using the OUT command or other corresponding commands; use!OUT commands if immediate refreshing is necessary.

Additional features in the CJ series include output terminals that are used for typical outputs, which can also be used for pulse outputs, origin Searches, and Pulse Width Modulation (PWM). One output terminal may only perform one of these functions at a time. For instance, if Output Terminal 4 is set to act as Normal Outputs, PWM output 0 and the error counter reset for Pulse Outputs will not function.

Standard Serial Communications with External Devices

The macro protocol function may send messages to and from conventional serial devices based on predefined parameter values in CJ-series PLCs. The macro protocol function provides for retries, timeouts, and error checks. Symbols that read or write data to a CPU Unit can be placed in communication frames to speed up information exchanges with the CPU Unit in CJ series PLCs.

However, Omron CQM1 series units attached to a Serial Communication unit through the Standard System Protocol are capable of transmitting messages via their peripheral ports or RS-232C ports; these devices communicate using one of three techniques:

  1. Host Link: The CQM1 may interface with a personal computer and a Programmable Terminal via the host link.
  2. RS-232C: The CQM1 can read bar code data and output it to a printer through the RS-232C.
  3. One-to-one Data Link: A data link can be established between two units if one has access to an additional port.


The calling and execution of subroutines by passing them inputs is one of the tasks performed by MACRO instructions. Using a statement to define a subroutine I/O word makes employing subroutines in Multiple Locations easier, simplifying the program.

Protocol Macros of CJ series PLCs can be used to develop adaptable Communication Functions for any PLC ports. The Communications Functions can be delivered to the Unit’s RS-232C Port or RS-422/485 Port and are known as Host Link Protocol Macro Configurations, NT Link Configurations, or Protocol Macro Configurations. The CPU unit as a whole can support up to 32 ports.

CQM1 provides macros with 64-bit inputs (IR 09600 to IR 09915) and 64-bit outputs (IR 19600 to IR 19915). In the CJ series, network instructions (SEND(090), SEND2(491), RECV(098), RECV2(492), CMND(490), CMND2(493), serial communications instructions (TXDU(256) and RXDU(255)), or protocol macro instructions (PMCR)(260 and PMCR2)(264) employ each communication port.

This entry was posted on November 28th, 2022 and is filed under Uncategorized. Both comments and pings are currently closed.

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