Siemens ST PCS 7 User Manual

ET 200iSP distributed I/O

Siemens ST PCS 7 · November 2007

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The current range of electronics modules covers: 
• 8-channel digital input module DI NAMUR, can also be used 

as counter or frequency meter

• 4-channel digital output module DO with external actuator 

switch-off via High or Low signal (H/L switch-off)

• 4-channel analog input modules AI for temperature measure-

ments with resistance thermometer (RTD) or thermocouple 

(TC)

• 4-channel analog input modules AI for connection of 2/4-wire 

transmitters with or without HART functionality

• 4-channel analog output module AO for connection of field de-

vices with or without HART functionality

A TC sensor module for internal temperature compensation is 

provided with the 4 AI TC module, and is fitted on the corre-

sponding terminals of the associated terminal module. External 

compensation is possible for the 4 AI RTD module by connect-

ing a Pt100.
The DO modules have a switch-off function which is triggered by 

an external signal (High or Low) from a switch-off device in the 

hazardous area. This permits implementation of an external 

switch-off independent of the automation system (controller). It 

is also possible to combine several DO modules into a switch-off 

group for this purpose. The intrinsically-safe power supply for 

the switch-off device is either via the watchdog module or a sep-

arate intrinsically-safe source.

The watchdog module has two fundamental functions:
• Monitoring of the ET 200iSP remote I/O station for hardware 

failures (hardware lifebeat); external, applicative failure moni-

toring is also possible via an I/O address area of the module 

• Intrinsically-safe power supply for external actuator switch-off
The watchdog module must be plugged onto a terminal module 

(order separately). The first slot directly next to the interface 

module is provided for the watchdog module. You can use the 

same terminal modules for the watchdog module as for the elec-

tronics modules.

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Design
• The electronics modules are plugged as planned onto the cor-

responding terminal modules using screw-type systems 

(TM-EM/EM60S) or spring-loaded systems (TM-EM/EM60C). 

The terminal modules must be ordered in addition.

• The mechanical coding of the terminal module which is car-

ried out when an electronics module is plugged on for the first 

time prevents the connection of incorrect replacement mod-

ules.

• Hot swapping of individual modules is possible under hazard-

ous conditions.

• The process signals are connected to the terminals of the ter-

minal modules assigned according to the plan, using either 

conventional screw-type or spring-loaded systems (conduc-

tor cross-sections 0.14 to max. 2.5 mm²) depending on the 

type of module.

• All electronics modules are implemented in the EEx i "intrinsi-

cally safe" degree of protection and can be easily replaced 

under hazardous conditions (hot swapping).

• Using a spare module plugged onto a terminal module for 

electronics modules (TM-EM/EM60S/ TM-EM/EM60C), you 

can reserve a slot for any electronics modules or close a gap 

resulting from the design. The spare module can be simply re-

placed by the electronics module at a later point in time.

© Siemens AG 2007