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6.3.12.1 Attaching the pH/ORP coax cable.
Once the cable has been prepared, (Figure 26) attach it to the pH/ORP driver card. Remove the shield grounding nut, XE5,
and loosen the center conductor screw, XE6, as shown in Figure 47.
Figure 47 pH/ORP driver card coax connection
Insert the coax center conductor into the XE2 or XE6 terminal and tighten. Place the shield grounding nut on the post, screw
down and tighten. This nut is smooth for a reason. Do not over-tighten!
Remove the black plastic layer from the inner coaxial cable. This is present on all types of cable. In doing so, ensure that
individual threads of the bare wire shielding do not come into contact with the inner conductor.
6.3.13 ORP/pH Temp mA Input card
The purpose of the card is to have pH and Free chlorine on one driver card.
Any 2-wire pH sensor will work if the mV/pH is 59.1
Any 2-wire ORP will work if mV is in the range of +/- 1,500mV
The pH, ORP or temperature (Pt100 or Pt1000 only) sensors can be extended a maximum of 10 meters/ 30 feet from the
controller. For longer distances, use a 4-20mA sensor transducer and a 4-20mA input card.
The temperature input sensor can be an LM335¹ (10mV/°K) sensor or either a 100
Temperature can be used for display, control or compensation.
The 4-20mA input can be connected to an active or passive loop. This input is isolated from the motherboard.
Any 4-20mA input is acceptable; however, there is no square root operation for older flow meters as found in some boiler
rooms. (We have never provided this service.)
Enter any engineering units for the range. 4mA does not have to be 0.
Outer conductor (4) ̴ 10mm
Insulation (2) ̴ 7mm
Inner conductor (3) ̴ 7mm
Coax cables accompany pH and ORP sensors. If you shorten them, be sure
to create an end that is a good fit for the card termination.
Page 41 of 102
Mounting and Installation
Figure 48 Coax placement
Figure 50 Coax measurement
or 1000
RTD.
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