Page top

CS1W-CT021 / 041

SYSMAC CS-series High-speed Counter Units

CS1W-CT021 / 041

High-Speed, Flexible Control With A Wide Array of Features

General Specifications

Item CS1W-CT021/CT041
Unit type CS1 Special I/O Unit
General Specifications Conform to general specifications for SYSMAC CS1-series
Ambient Operating Temperature 0 to 55 ° C
Ambient Storage Temperature -20 to 75 ° C
Ambient Operating Humidity 10 to 90% without condensation
Internal Current Consumption 450 mA (CS1W-CT041), 360 mA (CS1W-CT021) (at 5V via backplane)
Dimensions 35 × 130 × 100 mm (W × H × D)
Weight 245 g
Mounting Position CS1 CPU Rack or CS1 Expansion Rack
(Cannot be mounted to a C200H Expansion I/O Rack or a SYSMAC BUS Slave Rack).
Maximum Number of CT021/CT041
Units per Rack
Equal to the number of slots of the Rack *1
Maximum Number of CT021/CT041
Units per basic CS1-system
24
Data Exchange with CPU Unit I/O Refresh Data Area (CIO-bits 200000 to 295915, CIO-words 2000 to 2959): *2)
Special I/O Unit DM-Area (D-words 20000 to 29599): 400 DM-words per Unit are transmitted
form the CPU to the Unit at Power Up or when the Unit is restarted *3

*1. The maximum number of Units per Rack is also depending on the maximum supply current of the Power Supply Unit
       and the current consumption of other Units on the Rack.
*2. Both the CS1W-CT021/CT041 Special I/O Units are allocated words for 4 Units in the Special I/O Unit (CIO) Area.
*3. Both the CS1W-CT021/CT041 Special I/O Units are allocated words for 4 Units in the Special I/O Unit DM-Area. From
       the 400 DM-words that are allocated to the CT041 only the first 203 words are used to make the DM-settings. The
       remaining 197 DM-words can be used as work-words in the PLC Ladder Program. For the CT021 the first 113 words
       are used to make the DM-settings and the remaining 287 words can be used as work-words.

Functional Specifications

Item CS1W-CT021/CT041
Number of Counters 2 run-time configurable Counters for the CS1W-CT021
4 run-time configurable Counters for the CS1W-CT041
Counter Type Simple Counter
Circular Counter
Linear Counter
The Counter Type can be chosen by DIP switch at the back of the Unit. By default the Counters are
set to Simple Counter.
Maximum Input Frequency 500 kHz
Maximum Response Time 0.5 ms
Signals per Counter Phase A, B and Z
Digital I/O 4 Digital Inputs (I0, I1, I2 and I3):
Every Digital Input can be assigned to a Counter. In this way one Counter can be controlled by a
maximum of 4 Digital Inputs.
4 Digital Outputs (O0, O1, O2 and O3):
The Unit Output Pattern represents the 4 Digital Outputs and 28 Soft Outputs.
Input Signal Types Phase Differential (multiplication × 1), (multiplication × 2) * and (multiplication × 4) *
Up/Down *
Pulse & Direction *
Counter Control using
CIO-software bits
Open Gate/Start Counter: Counter is enabled to count pulses
Close Gate/Stop Counter: Counter is disabled to count pulses
Preset Counter: Preset Value can be set in CIO
Reset Counter to zero
Capture Counter Value: Captured Counter Value can be read using IORD-instruction
Digital Input Functionality Gate *
Reset *
Preset *
Capture *
Stop/Capture-Continue *
Stop/Capture-Reset/Continue *
Capture/Reset *
Enable Reset *
Disable Reset *
For every Function the corresponding action can be triggered on a rising- or on a falling edge.
Output Control Mode Automatic Output Control in:
Range Mode *
Comparison Mode *
Rate Range
Manual Output Control
Output State Control On changing the Operating Mode of the PLC from RUN/MONITOR → PROGRAM, an I/O Bus Error or an
Overflow/Underflow Error, the Digital Outputs can be configured to:
Continue automatic updating Output States
Freeze Output States *
Predefine Output States *
Output Driver Configuration The Output Driver of every Digital Output can be configured as:
NPN
PNP *
Reset Signals Every Counter can be reset to zero by (a combination of) the following sources:
Software Counter Reset Bit
Digital Input *
Z-Input *
Extra Functions Programmable Output Pulse * :
To every Digital Output an ON-delay and/or a Pulse Duration [1 to 9999 ms] can be applied.
Rate Measurement * : For every Counter the Pulse Rate can be measured by defining a Time-Window
[1 to 9999 ms]. Up to a maximum of 64 Rate Values are stored in the Rate History Log File. Rate Values
from the Rate History Log File can be read using the IORD-instruction. Additionally for every Counter
two Rate Ranges can be defined that control the Outputs according to the measured Rate Value.
Hysteresis * : To prevent Outputs from being switched On and Off by very small fluctuations in the
Counter Value around Range Limits, for every Counter an Hysteresis-value [1 to 255] can be defined
(the Unit must in Range Mode).
Noise Filtering Counter Inputs
and Digital Inputs
To suppress noise on the signal lines of the Counter Inputs (A and B) and the Digital Inputs (I0, I1, I2 and
I3) a Noise Filter can be configured:
10 kHz *
50 kHz (default)
500 kHz *
For the Digital Inputs the 500 kHz filter can not be selected. The Z-Input Signals of every Counter are
filtered with a fixed Noise Filter of 1 kHz.
Initial Counter Value The Initial Counter Value * is transferred to the Unit when the Unit is Powered Up or Restarted. The
Initial Counter Value is very useful to overcome problems in case of power failure.
IORD- and IOWR-instructions Run-time configuration and operation of the High-speed Counter Unit is possible by using IORD- and
IOWR-instructions. The following data can be read or written:
DM-configuration data *
Range- and Comparison Data *
Captured Counter Value
Rate History Log File Data *
Counter Value
(Re) Configure High-speed Counter Unit *
Error Clear
Interrupts of Outputs The Digital Outputs and the Soft Outputs of the Unit Output Pattern can all be configured to generate
interrupts to the CS1-CPU * .
Interrupts of Digital Inputs The Digital Inputs can all be configured to generate interrupts to the CS1-CPU * .
Error History Log Function Stores up to 30 error log records

*1. This specification item is only supported for Circular and Linear Counters (not for Simple Counters). For a complete
       overview of the differences between Simple and Circular/Linear Counters refer to High-speed Counter Units
       Operation Manual (Cat. No. W902).
*2. If an IOWR- or IORD-instruction is used during operation, comparison will stop during instruction execution. Care
       must be taken, therefore, with the timing of executing instructions.

Input Specifications

Item Counter Inputs A and B Digital Inputs
(I0 and I1)
Input Voltage 24 VDC
(19.6 to 26.4 V)
12 VDC
(9.8 to 13.2 V)
5 VDC
(4.5 to 5.5 V)
Line Driver 24 VDC
(19.6 to 26.4 V)
Input Current (typical) 8 mA 8 mA 7 mA 11 mA
Connectable to RS-422 compatible
Line Drivers.
7.6 mA
ON Voltage (min.) 19.6 V 9.8 V 4.5 V 19.6 V
OFF Voltage (max.) 4 V 2.5 V 1.5 V 4 V

Item Counter Input Z
Input Voltage 24 VDC (18.6 to 26.4 V) 12 VDC (9.8 to 13.2 V) 5 VDC (4.5 to 5.5 V) Line Driver
Input Current (typical) 7.3 mA 6.6mA 6 mA 11 mA
Connectable to RS-422 compatible
Line Drivers.
ON Voltage (min.) 18.6 V 9.8V 4.5 V
OFF Voltage (max.) 4 V 2.5V 1.5 V

Note: 1. The Counter Inputs (A, B, Z) are insulated from each other and from the Digital Inputs. The Digital Inputs are also
              insulated from each other. All Counter Inputs and Digital Inputs are reverse polarity protected and insulated
              from the I/O-bus.
           2. For every pair of Digital Inputs (I0 & I1, I2 & I3) a noise filter can be configured (10 kHz or 50 kHz (default)).
                Every Z-Input has a defined noise filter of 1 kHz.

Counter Inputs A, B, Z and Digital Inputs
5/12/24V input signals RS-422 Line Driver signals
Counter inputs A and B
Input pulses with a duty factor of 50%


Relationship between A and B phases with phase
differential inputs


Counter Input Z */Digital Inputs (24 V)


*Maximum allowed frequency of Z-pulses is 1 kHz
Counter inputs A and B
Input pulses with a duty factor of 50%


Relationship between A and B phases with phase
differential inputs


Counter Input Z *


* Maximum allowed frequency of Z-pulses is 1 kHz

Filter Selection Timing requirement (μs)
A B C D E F G H I J
10 kHz <3 >50 >100 >23 >10 >100 >50 >100 >23 >10
50 kHz <3 >10 >20 >4.5 >10 >20 >10 >20 >4.5 >10
500 kHz - - - - - >2 >1 >4 >1 >10

Note: As a general guideline it can be stated that if you want the timing requirements for the Counter Inputs to satisfy the
          above mentioned specifications, you must pay attention to the type of output driver of the encoder being used, the
          length of the encoder cable and the frequency of the count pulses generated. For example, if you use an E6B2-type
          Open Collector encoder (e.g. E6B2-CWZ6C) at 24 V with 10 m cable, you can typically generate count pulses up to
          20 kHz. Therefore, if you want to generate count pulses with higher frequencies, you should use a different type of
          encoder (e.g. E6B2-CWZ1X with Line Driver output or a fast push-pull 24 V encoder, e.g. E6C3-CWZ5GH
          (Complementary output)) or reduce the length of the encoder cable.

Output Specifications

Item Specification
Driver Type Open Collector (NPN/PNP selectable)
Operating Voltage Range 12 to 24 V (10.2 to 26.4 V) 30 mA max. at 26.4 VDC (for PNP output, without load current)
Maximum Switching Capacity 46 mA at 10.2 V to 100 mA at 26.4 V (400 mA maximum/common) (see picture below)
Minimum Switching Current 5 mA
Output ON-delay 100 μs max.
Output OFF-delay 100 μs max.
Leakage Current 0.1 mA max.
Residual Voltage 1.5 V max.
Short Circuit Protection None

Note: 1. Every Digital Output has 2 Output drivers available: NPN and PNP (available as separate pins on the front
              connectors). Every Output can be separately (DM-) configured for NPN or PNP. By default the Outputs are
              configured as NPN-output.
           2. The Digital Outputs are insulated from the I/O-bus but not from each other. They are not short circuit protected.
           3. The Output current must not exceed 400 mA per common (i.e. per 4 Digital Out-puts) otherwise the unit will be
                 damaged.
           4. The Outputs can be automatically or manually controlled (DM-setting) by using Manual Output Control in CIO.
           5. The state control of the 32 Outputs, in case the operating mode of the PLC-CPU is changed from RUN/MONITOR
                 → PROGRAM, an I/O Bus error or an Overflow/Underflow error occurs, can be configured.

Maximum Switching Capacity

The maximum switching current depends upon the power supply voltage, as shown below.

CS1W-CT021 / 041 Specifications 13