Novanta v30, Руководство пользователя, Страница: 54 / 101

INTERFACE CONNECTIONS PAGE | 54
DB-9 input circuitry
The Interface A (DB-9) connector has two user inputs—a PWM input and an enable input. As described in Table 3-3, PWM Positive and
PWM Negative are optoisolated to fully isolate PWM Command signals from other inputs and outputs. The Laser Enable input is ESD
protected, but is not optoisolated, so this input signal must be conditioned by the user
Figure below illustrates the input circuit’s equivalent internal schematic while the prior table on the following page provides DB-9 input
circuit specifications.
Figure 3-5 DB-9 input equivalent schematic
Table 3-4 DB-9 input circuit specifications
Do not apply a Laser Enable signal until the OEM v30’s in5 VDC power supply has stabilized
(approximately 200 ms after DC power-up).
Input Signals Input device type and specifications
PWM Positive Input
High-speed optoisolator LED, forward voltage drop (Vf) 1.5 VDC Off state
Vmax +0.8 VDC On state Vmin +3.5 VDC @ 5 mA on state (continuous)
Vmax +6.7 VDC @ 10 mA Frequency, max. 100 kHz
Laser Enable
5V logic input buffer Off state Vmax +0.8 VDC On state Vmin +2.0 VDC @
0.2 mA on state (continuous) Vmax +5.0 VDC @ 0.5 mA
Warning: Serious Personal Injury
Always use shielded cable when connecting your PWM Command signal source to PWM
Positive/PWM Negative inputs. In electrically-noisy environments, long lengths of unshielded wire act
like an antenna and may generate enough voltage to trigger uncommand lasing.