Operating instructions

Charged Aerosol Detectors
Corona Veo and Corona Veo RS
Operating Instructions Page 129
11 Appendix
11.1 Digital I/O Pin Assignment
The four TTL inputs and three relay outputs on the rear panel of the detector provide the
connection terminals for external devices.
For details about the TTL inputs, see page 130.
For details about the relay outputs, see page 131.
Digital I/O Terminal A
Pin Signal Name Signal Level Remark
1 CC1+ Relay output Positive polarity
2 CC1- Relay output Negative polarity
3 GND Ground
4 CC2+ Relay output Positive polarity
5 CC2- Relay output Negative polarity
6 GND Ground
7 Divert+ TTL input Positive polarity
8 Divert- TTL input Negative polarity
9 GND Ground
Fig. 27: Pin assignment Digital I/O terminal A
Digital I/O Terminal B
Pin Signal Name Signal Level Remark
1 Pump Off+ Relay output Positive polarity
2 Pump Off- Relay output Negative polarity
3 GND Ground
4 Gas Off+ TTL input Positive polarity
5 Gas Off- TTL input Negative polarity
6 GND Ground
7 Autozero+ TTL input Positive polarity
8 Autozero- TTL input Negative polarity
9 GND Ground
10 Start+ TTL input Positive polarity
11 Start- TTL input Negative polarity
12 GND Ground
Fig. 28: Pin assignment Digital I/O terminal B