Safetran Model 2000 Micro Motion Sensor
Posted: Wed Apr 08, 2009 8:46 pm
Here's what a Safetran Model 2000 Micro Motion Sensor looks like...
Here's the display and keypad up close. If you notice, there are 2 numbers displayed on this keypad. The EZ is the percentage out the train is on the approach from the island. When there isn't a train...the number is supposed to be 100...but of course...do to a number of factors...it usually stays in the 96 to 100 range. When a train enters the approach...that number begins to decline...and as the train comes onto the island...it reads 0. This is how a predictor can determine if the train is moving fast...slow...or not moving at all...depending on the rate of change of the EZ. The EX is the track ballast condition...and that ranges between 50 and 90 usually. The lower the number...the worse the track condition is due to rain...snow...or other environmental factors. If the number goes below 50...the crossing will drop out...as the conditions are too poor to detect a train properly. Also, with the EZ...if it goes above 115...the crossing will also drop out...because that is a High EZ error. That could mean a bad termination shunt...or a broken bond. Usually, if a bond breaks...the number is around 130...but I've seen it go as high as 300. The "STATUS T1" means you are looking at track 1. This unit is able to have 2 tracks to monitor. You change the tracks by pressing 1 or 2...
Here's the display and keypad up close. If you notice, there are 2 numbers displayed on this keypad. The EZ is the percentage out the train is on the approach from the island. When there isn't a train...the number is supposed to be 100...but of course...do to a number of factors...it usually stays in the 96 to 100 range. When a train enters the approach...that number begins to decline...and as the train comes onto the island...it reads 0. This is how a predictor can determine if the train is moving fast...slow...or not moving at all...depending on the rate of change of the EZ. The EX is the track ballast condition...and that ranges between 50 and 90 usually. The lower the number...the worse the track condition is due to rain...snow...or other environmental factors. If the number goes below 50...the crossing will drop out...as the conditions are too poor to detect a train properly. Also, with the EZ...if it goes above 115...the crossing will also drop out...because that is a High EZ error. That could mean a bad termination shunt...or a broken bond. Usually, if a bond breaks...the number is around 130...but I've seen it go as high as 300. The "STATUS T1" means you are looking at track 1. This unit is able to have 2 tracks to monitor. You change the tracks by pressing 1 or 2...
