Just looking for opinions here...
To prevent employees from coming into contact with a large, rotating butter churn, a light curtain was installed that stops the churn and applies a brake if the beam is interrupted. However, the beam is also interrupted by a hopper that is rolled into position near the churn so the butter can be dumped. In order to position the churn and to get all the butter out, the churn must be jogged. The light curtain is in series with several E-stops, a two churn door safety switches and a stop button. If any of the safety devices are tripped, the MCR unlatches and the system must be reset (armed) by pressing a start/reset button.
I have no choice but to by-pass the light curtain while the hopper is in place.
Here are some of the things I've been pondering:
1. A momentary push-button in parallel with the light curtain NC contact. The button would have to be pressed continuously while re-arming the system and while jogging. If the button were to be released, the MCR would unlatch. If nothing else, this would be very inconvenient and cumbersome for the operator.
2. Could I use something like an RFID safety switch (the chip on the hopper and the reader attached to the churn base) to by-pass the light curtain? The reader would be attached permanently to a swing-arm that the operator would move towards the chip once the hopper is in place.
3. A cheaper and simpler solution may be to use a key attached to the hopper that will only reach the control panel when the hopper is in the "dump" position. The key switch would by-pass the light curtain.
I would appreciate any feedback and suggestions
To prevent employees from coming into contact with a large, rotating butter churn, a light curtain was installed that stops the churn and applies a brake if the beam is interrupted. However, the beam is also interrupted by a hopper that is rolled into position near the churn so the butter can be dumped. In order to position the churn and to get all the butter out, the churn must be jogged. The light curtain is in series with several E-stops, a two churn door safety switches and a stop button. If any of the safety devices are tripped, the MCR unlatches and the system must be reset (armed) by pressing a start/reset button.
I have no choice but to by-pass the light curtain while the hopper is in place.
Here are some of the things I've been pondering:
1. A momentary push-button in parallel with the light curtain NC contact. The button would have to be pressed continuously while re-arming the system and while jogging. If the button were to be released, the MCR would unlatch. If nothing else, this would be very inconvenient and cumbersome for the operator.
2. Could I use something like an RFID safety switch (the chip on the hopper and the reader attached to the churn base) to by-pass the light curtain? The reader would be attached permanently to a swing-arm that the operator would move towards the chip once the hopper is in place.
3. A cheaper and simpler solution may be to use a key attached to the hopper that will only reach the control panel when the hopper is in the "dump" position. The key switch would by-pass the light curtain.
I would appreciate any feedback and suggestions