Siemens 6ES5390-5AA22 Timer Counter

Technical Specifications and Functional Design

This timer/counter module provides dedicated timing and counting functions for SIMATIC S5 PLCs. The Siemens 6ES5390-5AA22 handles high-speed events without burdening the CPU scan cycle. You can install this unit into any standard S5-115U or S5-135U rack slot. Its dedicated hardware processes pulses independently from the main processor. The module weighs approximately 0.48 kilograms. Its dimensions measure 25 cm in height, 5 cm in width, and 21 cm in depth.

Parameter	Specification
Brand	Siemens
Model	6ES5390-5AA22
Category	Timer/Counter Module / Dedicated Counting Unit
Weight	0.48 kg
Height	25 cm
Width	5 cm (single slot)
Depth	21 cm
Number of Counters	4 independent counters
Number of Timers	4 independent timers
Maximum Count Frequency	10 kHz per channel
Counter Resolution	16-bit (0 to 65,535 counts)
Timer Range	0.01 seconds to 999 minutes
Input Voltage	24V DC (nominal)
Input Current per Channel	10 mA typical
Output Type	Transistor (sourcing)
Output Current per Channel	0.5 Amps maximum
Response Time	0.1 milliseconds typical
Energy Storage	None (no battery)
Component Count	Single PCB with 8 counter ICs and isolation circuits

Counter Modes and Operational Features

Each counter operates in up, down, or up/down counting modes. You can set a preset value for automatic output activation. The Siemens 6ES5390-5AA22 accepts count enable and reset signals externally. A built-in direction input allows bidirectional counting from encoders. The module stores the current count value in non-volatile memory. Consequently, the module retains counts even after power loss. Four LEDs display the status of each output point clearly.

Timer Modes and Functionality

Each timer operates as ON-delay, OFF-delay, or pulse timer modes. You can set the time base to 0.01, 0.1, 1, or 10 seconds. The Siemens 6ES5390-5AA22 uses a crystal oscillator for precise timing accuracy. This oscillator maintains ±0.01% timing accuracy across the temperature range. The module triggers timing sequences from 24V DC input signals. Each timer includes a running status indicator for troubleshooting. The timer outputs turn on or off based on the elapsed time value.

Installation and Wiring Guidelines

You must insert this module into any standard S5 I/O rack slot. The backplane supplies 5V DC and 24V DC power automatically. The Siemens 6ES5390-5AA22 uses a front-panel screw terminal strip for field wiring. You should use shielded cables for counter inputs near inverters or drives. This practice prevents false counting from electrical noise interference. The module draws approximately 150 mA from the 5V supply rail. It requires no external power supply for normal operation.