3 – 78 HEIDENHAIN Technical Manual TNC 426, TNC 430
3.15 Switching Outputs 24 Vdc (PLC)
Output signals and 
addresses
The switching outputs are transistor outputs with current limitation.
Please note:
n Permissible load: Resistive load – inductive load only with quenching diode 
parallel to inductance
n Short circuiting of one output is permissible. No more than one output 
may be short-circuited at one time.
n No more than half the PLC outputs may be driven at the same time 
(simultaneity factor 0.5)
Output signals:
Addresses:
Logic unit PL 4xxB
Min. output voltage 
for “1” signal
3 V below supply voltage
Nominal operating 
current per output
0.125 A (simultaneity 
factor 0.5)
2.0 A (at max. PL current 
consumption of 20 A)
Note
The switching outputs need a minimum load of 5 mA. 
They conform to EN 61131-2.
Address Number Device
O0 to O30 31 Logic unit X41 (PLC output)
O0 to O7 8 Logic unit X46 (machine operating panel)
O32 to O62 31 First PLC input/output unit
O64 to O94 31 Second PLC input/output unit
O128 to O158 31 Third PLC input/output unit
O160 to O190 31 Fourth PLC input/output unit