Gocator Line Profile Sensors: User Manual
Safety and Maintenance • 15
Power-On Delays
A delay circuit is required that illuminates warning indicators for a short period of time before supplying
power to the lasers.
Beam Attenuators
A permanently attached method of preventing human access to laser radiation other than switches,
power connectors or key control must be employed.
Emission Indicator
It is required that the controls that operate the sensors incorporate a visible or audible indicator when
power is applied and the lasers are operating. If the distance between the sensor and controls is more
than 2 meters, or mounting of sensors intervenes with observation of these indicators, then a second
power-on indicator should be mounted at some readily-observable position. When mounting the
warning indicators, it is important not to mount them in a location that would require human exposure
to the laser emissions. User must ensure that the emission indicator, if supplied by OEM, is visible when
viewed through protective eyewear.
Warning Signs
Laser warning signs must be located in the vicinity of the sensor such that they will be readily observed.
Examples of laser warning signs are as follows:
FDA warning sign example IEC warning sign example
Nominal Ocular Hazard Distance (NOHD)
Nominal Ocular Hazard Distance (NOHD)is the distance from the source at which the intensity or the
energy per surface unit becomes lower than the Maximum Permissible Exposure (MPE) on the cornea
and on the skin.
The laser beam is considered dangerous if the operator is closer to the source than the NOHD.
The following table shows example calculations of the NOHDvalues for each Gocator model and laser
class, assuming continuous operation of the laser. As a configurable device the Gocator, lets you set the
laser exposure (laser on-time) independently of the frame period (total cycle time for data acquisition).
Continuous operation of the laser means that the laser exposure is configured to be identical to the
frame period, which is also referred to as 100% duty cycle. However, in many applications the laser
exposure can be smaller than the frame period (less than 100% duty cycle) thereby reducing the NOHD.
The table therefore shows the worst-case NOHD.
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