OZONE ANALYZER BMT 964 Manual, Rev. 04/2021
10
Input current at the binary input is approx. 18 mA. The input is protected against voltages with
wrong polarity.
Binary Outputs
Pin Function Description see page
9 Lamp Low Opens when the lamp becomes too weak 25
12 High Alarm Opens or closes if concentration is above a certain threshold 25
13 Low Alarm Opens or closes if concentration is below a certain threshold 25
14 Cuvette Dirty Opens when a dirty cuvette is detected 26
2 Purge Contact for external pump / solenoid valve 23
The binary outputs are relay contacts, which are used to signal errors and alarms. An additional
contact is used for the selection of purge gas during automatic zeroing. The common contact of
all binary output relays is on pin 8. The following outputs are available:
The binary output contacts can switch a max. voltage of 28 V and a max. current of 0.5 A. The
binary outputs can be used as "high-side switches" (voltage applied to pin 8) or "low-side switch-
es" (pin 8 connected to ground). Further explanations of the different output functions can be
found on the pages mentioned.
Error Relay
The error output is an SPST relay contact. In order to prevent a broken wire from remaining
undetected, the contact has been designed as opening on error (normally closed closed if there
is no error), see page 25 for more details on error handling. The contact may be loaded
with 30V/1A. The error output is isolated to the binary outputs mentioned above.
In the warm-up phase and if the instrument is powered off, the error relay is in the error state.
Serial Interface (RS-232):
The bidirectional isolated serial interface is used for communication with a PC or other automa-
tion components in an industrial environment.
Connection:
Pin Function Description
2 TxD Data sent
3 RxD Data received
5 GND RS-232 ground
Note: The RS-232 GND and isolated analog outputs GND are connected!
The data format used is eight bits, one stopbit, no parity (8N1). See page 19 for configuration of
the interface.
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