Earth Stake; Standby Battery; Volt Dc Operation - Toro Micro-Master Series User Manual

An example of correctly terminated valve wiring is shown below.
4.5

Earth Stake

The Micro-Master Touch controllers have a high level of field surge protection (4500 amp 20usec).
For this to work effectively, a good low resistance earth path must be provided to shunt the surges. A
resistance value <10 ohms is acceptable. A resistance value between 10-30 ohms is marginal. A
resistancevalue higher than 30 ohms is not acceptable. In severe lightning areas a 2 metre earth
stake connected to one of the GND terminals can be used ( Use multi-strand 4-6mm wire ).
Ensure soil around the earth stake is kept moist to create a good earth.

Standby Battery

4.6
The Standby Battery is a 9V alkaline MN1604 miniature Battery. This will give several hours of
standby time. The alkaline battery is essential in high temperature conditions as they have a shelf
life of approximately 5 years at 40 degrees Celsius. In the long term, an alkaline battery will be more
reliable and cheaper than an equivalent NiCad battery. They are replaced every 1 to 2 years
depending on the number of power failures in the area.
Note: For extreme conditions with many power failures, a battery holder with (6 AA alkaline cells) will
give an increased Standby time.
NI-Cad (Nickel Cadmium ) batteries should not be used for 2 reasons.
1. For a Ni-cad to be efficient, the operating cycle should be fully charged, then fully discharged.
This is not the case for a Standby battery in an irrigation controller.
2. Poor operation in a high temperature environment. The capacity is only 20% of an alkaline cell
and this is further reduced in high temperature environment.
The 216 standard carbon zinc battery should not be used because of very poor high temperature
performance and low capacity.
4.7

12 Volt DC Operation

The Touch Series controllers can be easily changed to operate on 12VDC. It should only be used
with caution as valves must be fitted locally as wires carrying DC current should not be installed
under ground because of electrolysis. Ideal installation when hydraulic valves are used.
© 2014 Toro Australia Pty Ltd
Micro-Master Touch User Guide
Figure 7 - Wiring Terminal Blocks
11 Ver 1.2, June 2014