Harris Atlas DVL400, Technical Manual

Page: 141 / 180

2/25/03 888-2473-001 4-41
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation
ATLAS Series™
4.6.4.1 Transmitter Interconnect
The pump control panel connects to the transmitter External I/O board. The X2
connector on the Pump Control Box is a pin for pin connection to the J12 connector
on the External I/O board.
4.6.4.2 Front Panel Controls
The Pump Control Panel has the following controls:
a.
Primary ac disconnect or Isolator switch, S1 - This disconnects the ac from
the pump module and the heat exchanger. It also disconnects the single phase
power to the step-down transformer T1 which is used to supply 24Vac and
+34Vdc to the pump control circuitry.
b. Local/Remote Switches
1.
Remote - This is the normal operating mode. Pressing the Remote but-
ton will place latching relays K3 and K9 in the position shown on the
Cooling System Electrical Diagram (843-5396-865 for 3 phase or 843-
5396-880 for single phase systems). This allows the Pump A and Pump
B select lines from the transmitter to control which pump is being used.
The Pump A Select line from the transmitter would pass through K9
and activate K1 and K5. The Pump B Select line would pass through
K9 and activates K2 and K5. Relay K3 sends an active low Remote sta-
tus output to the transmitter for operator status and lights the Remote
LED H2 on this control panel.
2.
Local - Pressing the Local button switches K3 and K9 to the opposite
position to that shown on the schematic. In Local mode K9 disconnects
the remote pump select lines from the transmitter in favor of the local
Pump A or Pump B pre-sets on the front of this control panel via latch-
ing relay K4. Relay K4 is shown in the Pump A position. Relay K3
sends a high (Remote not selected) status output to the transmitter for
operator status and lights the Local LED H3 on this control panel.
NOTE:
Switching from Remote to Local could cause a pump switch from A to B or
from B to A depending on the transmitter pump selection and the local con-
trol panel Pre-Set selection. If a pump switch is NOT desired, then the Pump
A/Pump B Pre-Set button selection should match the active Pump status
LEDs Pump A ON/Pump B ON before changing from remote to local.
c. Pump A/Pump B - These buttons are considered Pre-Sets because they do not
have any control over pump selection when the control panel is in Remote
mode. Pressing the Pump A button will place latching relay K4 in the position
shown. This will light Pump A Pre-Set LED H7, and will select Pump A only