Should I consider using Lithium Batteries rather than the pre-installed Panasonic ones? How much additional life would Lithium give?
You may certainly switch the batteries, or order lithium batteries from Tehama. However you will not see any significantly longer life, perhaps 5% at most. Lithium batteries ARE recommended if the MDT will experience sub-freezing temperatures or daily temperature swings in excess of 30º F.
What are the input requirements for the pulse MDT?
The MDT assumes a dry contact connection for the pulse input. The Pulse input is tied high to the battery voltage (nominally 3.0V) through a high impedance pull-up resistor. Closing the dry contact switch at the meter drives the pulse input low which generates a count. The meter switch must be closed for more that 25 mS to pass the MDT’s de-bounce logic.
Generated pulse meters (Badger RTR, Zenner, Hersey) also work with our MDT, however some of these meters generate a pulse shorter than 25mS (older Hersey, newer Zenner). Those meters require our “Hersey” MDT that does not implement the de-bounce logic.
The input signal from generated pulse meters should not exceed 4.5V. A generated pulse meter with a voltage value higher than this could damage the MDT (for example some Carlon water meters).
If we replace old Hersey Meters, will the existing Hersey MDT work with a reed switch type meter like a NMT VersaMag or MasterMeter FAM?
No. Hersey MDTs are Generated Pulse type meters, as are Badger Recordall and Zenner meters for example. If the Hersey MDT is connected to a reed switch meter, there is a very high potential the MDT will over-count due to the mechanical “bounce” of the reed switch.
Will an Encoded MDT automatically populate the meter's serial number field in the DCAP?
Yes, this information IS read by the Encoder MDT. Since it is static data, it is only sent once a day. Therefore it could take up to 24 hours for you to see the serial number in the CIT or your daily reports.