As example of input module with base unit -
ET200SP DI 16X24VDC ST   6AG1131-6BH00-7BA0
BASEUNIT TYPE A0, BU15-P16+A0+2B  6ES7193-6BP00-0BA0

Can these be mounted 'on the back' that is face upwards.

Would there be temperature de-rating if mounted like this ?

Thanks in advance

hi Ian,

normally the conditions are for horizontal or vertical mounting. 

See following manual:

SIMATIC ET 200SP Distributed I/O system

Installing position (page 39)

You can mount the ET 200SP distributed I/O system in any position. The preferred mounting

position is horizontal mounting on a vertical wall. It may be necessary to restrict the ambient

temperature in certain installation positions. You will find more information in the section

Mechanical and climatic environmental conditions (Page 221).

Climatic environmental conditions (page 223)

The table below shows the permissible climatic environmental conditions for the ET 200SP

distributed I/O system:

Table 14- 10 Climatic environmental conditions

Environmental conditions Permissible range Comments

Temperature:

horiz. mounting position:  0 to 60 °C

vertical mounting position:   0 to 50 °C

Permitted temperature change:  10 K/h 

Relative humidity:    from 10 to 95%      Without condensation, corresponds to relativehumidity (RH) stress grade 2 in accordancewith IEC 61131 part 2

Barometric pressure:   1080 hPa to 795 hPa    Corresponds to an altitude of -1000 to 2000 m

Concentration of pollutants:    SO2: <0.5 ppm; RH <60%, no condensation; H2S: <0.1 ppm; RH <60%, no condensation

ISA-S71.04 severity level G1; G2; G3

 hope this helps,

regards,