Hach 1735 TRO Manuel D'utilisation page 18

Message
LOW REFERENCE
COUNTS
HIGH ZERO COUNTS
Examine the 4-20 mA loop
Use this procedure when the 4–20 mA current loop does not work as expected. The manufacturer
strongly recommends the use of a 4–20 mA loop isolator with galvanic isolation to prevent ground
loop issues with this instrument.
1. Disconnect the wire from the negative (–) loop terminal and from the positive (+) loop terminal.
2. Use a handheld multimeter to measure the current between the positive (+) loop terminal and the
negative (–) loop terminal.
If the expected current shows on the multimeter during the test but not on the controller or logger
during normal operation conditions, a ground loop condition may exist.
3. Look for a shared connection to the power supply common terminal or to ground. Rewire as
needed or use a loop isolator.
Consumables
Note: Product and Article numbers may vary for some selling regions. Contact the appropriate distributor or refer to
the company website for contact information.
Description
1735 TRO Analyzer reagent set, includes:
1735 TRO buffer solution
1735 TRO DPD indicator powder
1735 TRO indicator solution
Replacement items
Description
Stir bar
1735 TRO cleaning kit
1735 TRO maintenance kit
18 English
Table 4 Error messages (continued)
Description
Reference counts are too low for the
instrument to operate
Zero counts are higher than the set limits.
Solution
Clean the colorimeter, then restart
the instrument.
Make sure that the plug is secure in
the top of colorimeter. Restart the
instrument.
Item no.
9397800
2999931
9400500
2999831
Item no.
6865600
9401300
9359100