Power Supply
(B- and C-Series)¶
C-series devices can be supplied with power via Power over Ethernet or via a 24V supply on the GPIO port. If a DC supply is connected it will be preferred over PoE.
The camera can internally buffer energy for approximately 1.5ms flash time at full output power, regardless of DC or PoE operation. After this period the actual output power will reduce to the power level available from the PoE or DC supply. If you need long flash times at full output power the camera should be powered via the DC supply.
Power over Ethernet¶
On PoE switches the camera registers as 802.3bt (“PoE++”) device with PD class 5 (40W). Even though the camera registers as PD class 5, which reflects the average device consumption, we currently only support operation on PoE++ equipment providing PD class 8 (90W). This is necessary to provide enough power headroom for longer projector flash times. Depending on the switch/injector model, cable length and number of connected devices on the switch the camera projection power may nevertheless need to be limited in software for stable operation for long flash times.
Note
Operation on PoE++ equipment providing less than PD class 8 (90W) is unsupported.
DC Supply¶
The camera can be powered via a 24V 10A DC supply on the GPIO port. The full 10A are only required for short periods during projector flashes. The device idle current is ~0.3A. The average current will be below 1.3A in all cases, due to LED duty cycle limits. For reduced power requirement the projection power can be reduced in software.
You should ensure at least 20V during peak current operation at the device and at most 27V maximum voltage when idle. When supplying increased voltage please make sure to leave a safety margin to the overvoltage protection (internal TVS diode) which will be triggered above 28.5V. DC voltage drops below 20V might result in reduced LED output power and the device could also intermittently switch to draw power from PoE if available.
Note
The devices are equipped with an internal 3.5A fuse with a mean opening time of 500ms at 10A.
Note
For protection of cabling against electrical faults use a power supply with 10A peak power and maximum 5A average power rating, or insert a slow blow fuse at the supply.
Long cable lengths¶
The high peak power requirement during projector flashes will limit the usable cable length with M8 cabling. To cover longer distances and still supply sufficient voltage during peak power phases at the device input we recommend the following measures:
use M12 cabling with sufficient wire cross section for covering most of the distance and attach an M12 5-pin to M8 4-pin adapter in front of the device.
you can supply up to 27V when the device is idle, which allows for more losses while still keeping the 20V minimum voltage level during peak power phases.
if these measures are not sufficient you can still limit peak power in software, which will come at a cost of slightly higher exposure times and slightly lower environmental light robustness.
Calculation Examples¶
The following table lists some examples of supply and wiring combinations for different distances.
Cable length, connector, supply |
Wire thickness |
Resistance, GND+Supply wire |
Voltage drop on cable |
Min. voltage at device during flash |
|---|---|---|---|---|
5m, M8 |
0.5mm² |
33mΩ/m * 5m * 2 = 0.33Ω |
0.33Ω * 10A = 3.3V |
24V - 3.3V = 20.7V |
10m, M8, 27V supply |
0.5mm² |
33mΩ/m * 10m * 2 = 0.66Ω |
0.66Ω * 10A = 6.6V |
27V - 6.6V = 20.4V |
15m, M12 |
1.5mm² |
12mΩ/m * 15m * 2 = 0.36Ω |
0.36Ω * 10A = 3.6V |
24V - 3.6V = 20.4V |
25m, M12, 27V supply |
1.5mm² |
12mΩ/m * 25m * 2 = 0.60Ω |
0.60Ω * 10A = 6.0V |
27V - 6.0V = 21.0V |
25m, custom adapter |
2.5mm² |
7mΩ/m * 25m * 2 = 0.35Ω |
0.35Ω * 10A = 3.5V |
24V - 3.5V = 20.5V |
50m, custom adapter, 27V |
2.5mm² |
7mΩ/m * 50m * 2 = 0.70Ω |
0.70Ω * 10A = 7.0V |
27V - 7.0V = 20.0V |
Note
Cables with lengths exceeding 29m will require custom adapters to accomodate wire cross sections larger than 1.5mm².
Example current draw plots¶
FlexView 4, 10ms exposure¶
Operation mode FlexView 4, 10ms exposure per frame, acquisition every 500ms. Notice that up to 10A current drawn in 4x10ms bursts at each acquisition, whereas the average current is around ~1.1A.
FlexView 1, 120ms exposure¶
Operation mode FlexView 1, 120ms exposure, one acquisition every 1.2s. Notice that up to 10A current drawn during the 120ms exposure at each acquisition, whereas the average current is around ~1.3A.
Note
The “FlexView 1, 120ms” case also represents the absolute maximum current requirement, as the LED flash pulse length is limited to 120ms and 10% duty cycle. See Illumination topic for flash time and duty cycle limits.