Siemens ET 200SP Manual page 17

Connecting
3.1 Terminal assignment and schematic circuit diagram
Sensor supply
To supply sensors connected to the digital inputs, the technology module supplies 24 V DC
at the 24VDC output (terminals 1 and 2) with reference to M (terminals 5 and 7 as well as 6
and 8). The voltage is monitored for short-circuit and overload.
Digital input DI0
The digital input DI0 is used for the hardware enable.
The digital inputs of the module are not isolated from each other.
Input delay for digital input
To suppress interference, you can configure an input delay for the digital input.
Note
If you select the "None" or "0.05 ms" option, you must use a shielded cable for connection of
the digital input.
Digital output DQA / DQB
The digital outputs of the module are not electrically isolated from each other or from the
digital inputs.
The digital outputs of the module are 24 V current-sourcing switches in reference to M and
can handle a rated load current of 2 A. They are protected against overload and short-circuit.
Relays and contactors can be connected directly without external circuitry. You can find
information on the maximum possible operating frequencies and the inductive loads at the
digital outputs in section Technical specifications (Page 148).
Digital outputs are equipped with integrated freewheeling diodes for preventing voltage
overloads due to inductive loads. Additional external freewheeling diodes can impair proper
operation.
DQ0.B and DQ1.B are used only in "PWM with DC motor" mode or are controlled using the
SET_DQB bit in the control interface.
Response of digital outputs to wire break at ground connections
Due to the characteristics of the output driver used in the module, approx. 50 mA supply
current drains through the digital outputs via a parasitic diode following a ground wire break.
This behavior may cause the digital outputs to be set from 0 to 1.
To prevent unintended switching of the outputs following a wire break at a ground
connection, follow these steps:
1. Route the first ground connection from terminal 14 to the ground connection of the central
power supply of the plant.
2. Route the second ground connection from terminal 16 to the ground connection of the
central power supply of the plant.
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Technology Module TM Pulse 2x24V (6ES7138‑6DB00‑0BB1)
Manual, 05/2019, A5E35061186-AB