Hach 1950Plus, Инструкция по эксплуатации инструмента, Страница: 41 / 188

Section 2
Page 41
UVTOCUnpacking Installation Setup.fm
Analog Outputs
2.4 Analog Outputs
Only Jumpers LK4, LK5, LK7, and LK8 relate to the analog outputs. The
default configuration on the I/O PCB assembly is 4–20 mA, no links (jumpers)
installed. These connections are labeled CH1 Analog and CH2 Analog.
Although isolated from the rest of
the electronics, the two 4–20 mA
circuits are not isolated from
each other.
Use shielded twisted-pair signal cable with the shield grounded at the receiver
end. Connect the positive signal lines to the I+ terminals and the negative
signal lines to the I– terminals. The maximum load for each analog output is
600 ohms. For on-site calibration of the 4–20 mA, see section
8.6.5 on page
143 . See Technical Specifications on page 13 for resistive load requirements.
The 4–20 mA analog outputs are
self-powered. The resistive load
should have no other
voltage connections.
Optionally, using links LK4, LK5, LK7, and LK8 (as described in Table 4 ), allow
the analyzer to be set for 0–10 V output or 4–20 mA output with
I– connected to ground (PE).
These settings are also detailed on the I/O PCB.
2.5 Serial Data Connections
Connection cables are user supplied and must be shielded to minimize
electromagnetic effects on analyzer performance. Refer to
Figure 19, Proper Wire Preparation and Insertion, on page 40 .
Using this option requires an RS232
or RS485 Kit. See
Replacement
Parts on page 165 for catalog
numbers.
The Serial Data Communication connection allows an optional kit to be
installed in the analyzer providing optically isolated user serial
communications capability to the analyzer. Both CSV data logging and
ModBUS communications are supported, allowing connectivity to simple and
complex communications equipment.
To ensure that ground currents in inadequate ground systems do not result in
potential shock hazards, connect the shield at only the analyzer end. When
wiring the other end, cut the shield wire off and remove it. Do not connect the
shield wire at both ends.
Table 4 Link Setting For Analog Output
Link
4–20 mA 10 Volt I– to PE (ground)
CH1 CH2 CH1 CH2 CH1 CH2
LK4 Yes
LK8 Yes
LK5 Yes
LK7 Yes