Hach-Lange SI794 C User Manual - Manual (Page 94)

94
According to the “USP” directive (U.S. Pharmacopeia), Section 645
“Water Conductivity”, the conductivity of pharmaceutical waters can
be monitored online. To do so, the conductivity is measured without
temperature compensation and is compared with limit values (see
“Temperature/ conductivity table according to USP” on Pg 95).
The water is usable if the conductivity is below the USP limit. For higher
conductivities, further test steps must be performed according to the
directive.
To increase safety, the USP limit value can be reduced in the transmitter.
To do so, a factor (%) is entered.
Configuration steps
• out1 menu group:
When USP function has been selected, the measuring range is
fixed to 00.00 ... 99.99 µS/cm. Temperature compensation is switched
off. Temperature is monitored (see Pg ).
• In the rL . menu group select USP as limit function.
Relays 1 and 2 can now be used as USP limit contacts
(see Pg ).
• Reduced limit contact U1 (Relay 1):
Enter USP factor (reduced limit, configurable in the range
10 % ... 100 %)
Set contact response for relay 1.
Set delay time (see Pg ).
• Limit contact U2
Set contact response for relay 2.
Set delay time (see Pg ).
USP function
35
57
63
63