Signals-R-Me
Close up of NEMA TS1 detection
This is the cabinet with the Phoenix Diamond traffic counter. The detection bay looks odd, with missing detectors and detectors partially pulled out. The reason is that when we worked with Diamond, they told us they could take a contact closure output from a traffic signal detector to place a contact closure into the count station. The cabinet was wired to accommodate this.
When we actually set it up in the field, we found that there was a difference between what Phoenix thought how detectors worked, and how they actually did. They wanted the voltage on the input to drop from 24 volts DC to around 0 volts DC to place the contact closure onto the count station. In reality, the traffic signal detector output drops to about 6 or 7 volts which is enough to trigger the traffic signal controller detection inputs, but not the count station detection inputs.
We worked on several fixes, but ended up getting the module for the count station that allowed it to be wired directly to the traffic signal loops, bypassing the vehicle detectors.
I was not particularly happy, as we bring back our loop wires in 4cc/s wire, with a pair of loops on each wire. We run these through a scanning loop amplifier, so we don't get cross talk. This has worked OK, but we are looking to modify it this year to provide better data.
Close up of NEMA TS1 detection
This is the cabinet with the Phoenix Diamond traffic counter. The detection bay looks odd, with missing detectors and detectors partially pulled out. The reason is that when we worked with Diamond, they told us they could take a contact closure output from a traffic signal detector to place a contact closure into the count station. The cabinet was wired to accommodate this.
When we actually set it up in the field, we found that there was a difference between what Phoenix thought how detectors worked, and how they actually did. They wanted the voltage on the input to drop from 24 volts DC to around 0 volts DC to place the contact closure onto the count station. In reality, the traffic signal detector output drops to about 6 or 7 volts which is enough to trigger the traffic signal controller detection inputs, but not the count station detection inputs.
We worked on several fixes, but ended up getting the module for the count station that allowed it to be wired directly to the traffic signal loops, bypassing the vehicle detectors.
I was not particularly happy, as we bring back our loop wires in 4cc/s wire, with a pair of loops on each wire. We run these through a scanning loop amplifier, so we don't get cross talk. This has worked OK, but we are looking to modify it this year to provide better data.