MAC155 Rev. 12 ©Copyright MAC Instruments 2005. All Rights Reserved.
Pg 50
DANGER! High Voltage is present inside the controller.
DANGER! High Voltage is present on the power supply heat sinks.
Power Supplies
There are three power supplies in the controller, a 5V supply and two 15V
supplies
The +5V supply powers only the processor card and the display of the
controller.
The +15V supply powers the current loop output, and Maintenance Relay
circuits which is located on the processor board in the controller. The +15V
power supply also supplies DC power to the MAC155 probe in addition to the
remaining -15V supply.
Each power supply has a green LED which indicates if voltage is present on
the output. The power supplies have a current limit function, so it is possible for
a short circuit to exist on the output of the supply without blowing any of the
fuses.
The power supply voltages can be measured at the 4 pin connector located
near the green LED on each power supply. The two pins closes to the green
LED are (+) positive and the remaining two are (–) negative.
An alternative measuring point is the +15V and +5V test points on the
processor board. The common for both of these test points is available near the
+5V test point.
LED Status Indicators
Loop Failure LED
To Next Page
Loading...