SECTION 14. INSTALLATION AND MAINTENANCE

TABLE 14.3-2. PS12LA Battery and ACTransformer Specifications
Lead Acid Battery

 

Battery Type

Yuasa NA 7-12

Float Life @ 25°C

5 years typical

Capacity

7.0 amp-hour

Shelf Life, full charge

Check twice yearly

Charge Time (AC Source)

40 hr full charge, 20

 

hr 95% charge

AC Transformer

 

Input:

120 VAC, 60 Hz

Isolated Output:

18 VDC @

 

1.11 A max.

There are inherent hazards associated with the use of sealed lead acid batteries. Under normal operation, lead acid batteries generate a small amount of hydrogen gas. This gaseous byproduct is generally insignificant because the hydrogen dissipates naturally before build-up to an explosive level (4%) occurs. However, if the batteries are shorted or overcharging takes place, hydrogen gas may be generated at a rate sufficient to create a hazard. Campbell Scientific makes the following recommendations:

1.A CR10 equipped with standard lead acid batteries should NEVER be used in applications requiring intrinsically safe equipment.

2.A lead acid battery should not be housed in a gas-tight enclosure.

14.3.3PS512M VOLTAGE REGULATOR WITH NULL MODEM PORTS

The PS512M 12 Volt Lead Acid Power Supply with Charging Regulator and Null Modem Ports is used when 5 volts is needed to power external modems besides the capabilities of the PS12LA. The PS512M supplies 5 volts to pin 1 of the 9 pin null modem ports, otherwise the capabilities and functions are identical to the PS12LA. A common use for the PS512M is in radiotelemetry networks. The PS12LA cannot be modified to a PS512M.

The maximum current drain on the 5 volt supply of the PS512M is 150 milliamps.

14-6