Hach 8450, Instrument Manual

Page: 19 / 66

Section 2
Page 19
16116Install.fm
4-20 mA Surge Protector
• Small straight-slot screw driver
• Milliampmeter
• Color-coded connection wire, 10 in. (25.4 cm)/test leads
• 4-20 mA Surge Protector(s) (Cat. No. 16326)
2.7.1 Connections and Setup
Warning: Remove ac power to the instrument before proceeding.
1. Remove electrical power to the meter.
2. Unscrew the four cover face plate screws and remove the cover.
3. Unscrew the upper and lower right screws that hold the display circuit
board to the meter and swing the hinged display board back to access the
main circuit board inside the case.
4. As shown in Figure 12 , insert the two pins of the Surge Protectors into
pins 7 and 8 (channel 1) and 5 and 6 (channel 2) on the terminal block.
5. Tighten the clamp screws on this connector.
Figure 12 Top View of Pins and Terminal Block
6. Connect the wires from the color-coded wire into surge protector terminal
screws. Route the wires through the bottom of the case (under the
display) and label the wires for channel 1 and 2 and + and –.
7. Temporarily tape the ends of channel 2 wires to avoid the possibility of
shorts. Connect a milliampmeter to the channel 1 extension leads.
8. Plug the screw-terminal block with attached surge protectors installed into
TB4 connector on the 8400 meter’s main circuit board (
Figure 13 .)
Note: The plug-in screw terminal connector is keyed to ensure that it plugs in correctly.
Note: The location of TB4 and its numbered terminals are marked on the main circuit
board.
Figure 13 Plug-in Connector in Place
9. Swing the display back into the closed position, using care to avoid
pinching or snagging wires (
Figure 14 ).
Figure 14 Extension Leads and Milliampmeter Connections
10. Power the meter on again and proceed to section 2.7.2 .