A032-ET - International Laser Ranging Service

Event Timer A032-ET3.2. ET-deviceThe ET-device is a desktop apparatus that contains the following connectors for wireconnections with external signal sources and with PC of the ET-server:On the front panel (Fig.10):INPUT A and INPUT B (BNC connectors, 50 Ohm impedance) - two electrically identical inputsof the events to be measured. Each event should be represented by a falling edge of a NIMstandardFast Negative Logic Signals (fall time: 0.5 V p-p). Maximum offset of this frequency (including the offset caused bylong-term deviation) should not exceed ±5 KHz. The external reference replaces the internalreference automatically after connecting. Located on the front panel LED “EXT REF”indicates the presence of the external reference.EVENT TIMERA032-ETEXT REFPOWERINPUT A INPUT B GATE IN REF IN (10 MHz)On the rear panel (Fig.11):Fig.10. Front panel of the ET-deviceSYNC IN (BNC connector, 50 Ohm impedance) – input of TTL sync pulses that define the realtime incrementing by 1 sec. (Note. It is supposed that both the reference signal and thesynch 1 pps pulses are mutually synchronized).TRIG IN (BNC connector, 50 Ohm impedance) - input of the TTL pulse that defines an externalstart of current measurement (can be used optionally).PARALLEL PORT (DB-25 connector) – connection to the PC parallel port. To avoid eventualproblems it is recommended to use only the provided cable for this connection.AUX (DB-9 connector) – provides auxiliary signals (currently not for user’s use).TEST OUT (BNC connector) – provides NIM signal for optional use. Specific kind of this signaldepends on the timer’s option.AUX OUT (BNC connector) – provides auxiliary signals (currently not for user’s use).AC 100-240 V – connector for device powering.POWER – switch for power On/Off (LED on the front panel indicates when power is On).POWERIOTEST OUTMADE IN LATVIASYNC IN TRIG IN AUX OUTAC 100-240 V(NIM) AUX PARALLEL PORT (1pps) (TTL) (TTL)Fig.11. Rear panel of the ET-device14