Range of product

Modicon M238 logic controller 

Product or component type

Compact base 

Discrete I/O number

24 

Discrete input number

6  input  EN/IEC 61131-2 type 1 
8  fast input  EN/IEC 61131-2 type 1 

Discrete input voltage

24 V 

Discrete input voltage type

DC 

Discrete output number

4  fast output 
6  output 

Discrete output voltage

24 V DC 

Number of I/O expansion module

7 

[Us] rated supply voltage

24 V DC 

Memory description

Internal RAM 512 kB 

Data backed up

Variables of type retain and retain persistent (internal battery) 3 days ,   22 h ,10 yr 
Variables of type retain and retain persistent (optional battery lithium thionyl chloride (TSXPLP01)) 1 year 

Mounting support

35 mm symmetrical DIN rail 
Panel 

Discrete input logic

Positive logic (sink)  fast input 
Sink or source (positive/negative)  input 

Number of common point

1  input 
1  fast output 
2  output 
4  fast input 

Sensor power supply

19,2...30 V DC 

Voltage state1 guaranteed

≥ 15 V  input/fast input 

Current state 1 guaranteed

≥ 2 mA  input/fast input 

Voltage state 0 guaranteed

≤ 5 V  input/fast input 

Current state 0 guaranteed

≤ 1,5 mA  input/fast input 

Discrete input current

8 mA  fast input 
10,4 mA  input 

Input impedance

2,3 kOhm  input 
3 kOhm  fast input 

Response time

0.25 ms  fast output 
3 ms  input 
300 ns  fast input 
< 1 ms  output 

Configurable filtering time

0,004 ms  fast input 
0,4 ms  fast input 
1 ms  fast input 
2 ms  fast input 
4 ms  fast input 

Anti bounce filtering

0 ms configurable  input/fast input 
1.5 ms configurable  input/fast input 
4 ms configurable  input/fast input 
12 ms configurable  input/fast input 

Input frequency

≤ 100 kHz  fast input (normal mode) 
≤ 100 kHz  fast input (counter mode) 
≤ 100 kHz  input 

Cable length

≤ 10 m  fast output (PWM or PTO mode) 
≤ 10 m , shielded cable  fast input (counter mode) 
≤ 30 m , shielded cable  fast output (normal mode) 
≤ 30 m  output 
≤ 30 m  fast input (normal mode) 
≤ 30 m  input 

Isolation between channels and internal logic

500 V DC 

Isolation between channels

500 V for group of 2 fast inputs 
500 V for output and fast output 
None input 

Discrete output logic

Positive logic (source) 

Output voltage limits

19.2...30 V 

Discrete output current

20...500 mA  output 
≤ 100 mA  fast output (PTO mode) 
≤ 100 mA  fast output (PWM mode) 
≤ 500 mA  fast output (normal mode) 

Output frequency

≤ 100 kHz  fast output (PTO mode) 
≤ 100 kHz  output 
≤ 20 kHz  fast output (PWM mode) 

Absolute accuracy error

0.01  fast output (PTO mode) 
1 % of full scale  cyclic ratio 20...80%  fast output (PWM mode) 

Leakage current

0,05 mA  output 
≤ 2 mA  fast output 

[Ures] residual voltage

≤ 2 V  output and fast output 

Tungsten load

≤ 3 W  output and fast output 

Short-circuit protection

With ,  output and fast output 

Overvoltage protection

With ,  output and fast output 

Overload protection

With ,  output and fast output 

Input/output number

≤ 136 , removable screw terminal block with I/O expansion module 
≤ 192 , spring terminal block with I/O expansion module 
≤ 248 , HE-10 connector with I/O expansion module 

Supply voltage limits

20,4...28,8 V 

Inrush current

≤ 35 A 

Power consumption in W

≤ 17,2 W 

Insulation resistance

> 10 MOhm at 500 V, between I/O and earth terminals 

Exact time for 1 Kinstruction

70 % Boolean + 30 % fixed arithmetic : 3 ms 

Execution time per instruction

Boolean : 0,971 µs 
Arithmetic DINT double-word : 0,506 µs  +, -, x operations 
Arithmetic DINT double-word : 0,459 µs  LD and ST 
Arithmetic INT word : 0,439 µs  +, -, x operations 
Arithmetic INT word : 0,42 µs  LD and ST 
Arithmetic REAL floating : 5,111 µs  +, -, x operations 
Arithmetic REAL floating : 7,25 µs  by operation 
Arithmetic REAL floating : 0,648 µs  LD and ST 

Exct time for event task

Arithmetic DINT double-word : 0,95 ms 
Arithmetic INT word : ≥ 0,75 ms 
Arithmetic REAL floating : ≤ 1,75 ms 

System overhead

0,15 ms  master task (PWM, frequency meter) 
0,15 ms  master task (simple counting) 
0,2 ms  master task (PTO) 
0,35 ms  master task (advanced counting) 
0,9 ms  master task (I/O) 

Input output assignment

Reading/writing I/O on base 
Reading/writing I/O on extension modules 

Application structure

1 configurable freewheeling/cyclic master task 
2 configurable freewheeling/cyclic/event auxiliary tasks 
4 interrupt tasks 
32 levels of priority between tasks 

Realtime clock

With , : 10 s/month  25 °C 

Integrated connection type

Isolated serial link female RJ45 Modbus master/slave RTU/ASCII, character mode or SoMachine-Network (RS232/RS485), 1.2...115.2 kbit/s (115.2 kbit/s by default) 

Supply

Serial link supply , 5 V  200 mA 

Positioning functions

PWM/PTO 2 100 kHz 

Counting input number

8 100 kHz , 32 bits 

Complementary function

PID 
Event processing 

Marking

CE 

Local signalling

1 LED , PWR 
1 LED , : RUN 
1 LED , : Batt 
1 LED , : module error (ERR) 
1 LED , : SL1 
1 LED per channel , : I/O state 

Electrical connection

1 connector mini B USB 2.0 for a programming terminal 
1 removable screw terminal block for connecting the 24 V DC power supply 
1 removable screw terminal block (10 terminals) for connecting the 4 preactuators (fast output) 
1 removable screw terminal block (12 terminals) for connecting the sensors (fast inputs) 
1 removable screw terminal block (6 terminals) for connecting the 6 preactuators (output) 
1 removable screw terminal block (7 terminals) for connecting the sensors (inputs) 

Product weight

0,56 kg