10K manual
Issue 1.0, 31st July 2019
Page 30
CALIBRATE SENSOR CABLE LENGTH VIA MODBUS
The length of sensor cable connected to the Aqualeak 10K can be calibrated through a
Modbus-enabled system. This helps fine-tune a distance-read leak detection system. If no
alarms are present, follow these steps to calibrate and test the system:
1.
Set the SW1 DIP switches for the correct cable resistance per foot, as shown in Figure
20.
Figure 20 SW1 DIP Switch settings for Ohms/Foot
2.
Press the Test/Reset button on the Aqualeak
10K once to verify the cable’s amperage
reading. Calibration cannot be performed if the current is above 15
A.
Different sensor cables are cleaned in different ways. The following cleaning
instructions apply to Aqualeak
’s orange sensor cable ONLY. If you
have questions
regarding the care and maintenance of your sensor cable, please consult the cable’s
data sheet or contact the manufacturer.
3.
If the sensor cable is new and the current is higher than 1
A, clean the cable.
Isopropyl alcohol removes any contamination that might have been introduced to the
cable during installation.
4.
If the cable is older and the amperage reading is above 15
A, clean the cable. A mild
dish detergent solution removes most dirt. Isopropyl alcohol is also an effective cable
cleaner.
5.
Sensor cable has a resistance. For example, Aqualeak
’s orange cable has a resistance
of 2.8 Ohms per foot. A system's actual resistance will rarely be exactly 2.8 Ohms per
foot, but it will be close. Each individual cable or system will vary a very small bit from
that 2.8 Ohms per foot value. If you know the exact resistance of your cable, you can
fine-tune your system for a more precise distance reading. The formula for calculating
this value, and more specific directions for using the formula, is as follows:
Formula for calculating exact cable resistance
6.
Read the Leg 1 and Leg 2 Resistance values in Modbus registers 30006 and 30007. Make
sure that the readings are similar: - within 2% of each other. This helps rule out any
major cable problems before calibration begins. Record the resistance reading from
Leg 2, Modbus register 30007.
7.
Add up all the lengths of sensor cable and any other equipment in the system that
simulates a length of cable. Record this value. Keep in mind:
•
Each weighted cable connector (WCCS-50) simulates 50 feet (15.24 m) of cable.
