pH 170/
pH 296
Installation
106
RS 485 digital interface (RS option)
The RS 485 interface operates with differential levels that are not susceptible to
interference. In this way, cable lengths of up to 1 km long can be implemented. The
instruments are connected via a 2-wire line. A twisted 3-wire line is recommended
for greater lengths or a larger number of instruments; the third line is used as a
reference potential (GND), to compensate for any possible differences in potential
that occur.
Terminate every bus with a resistor using the software (see Parameterizing).
The last device on the bus must provide the terminating resistor, i.e. in
parameterizing in the menu item
PIF
, the last device must have the termination
connected additionally within the bus connection (
tr
=
t
e
r
mination) and
disconnected (
notr
=
no
t
e
r
mination) in all other devices.
If only one device is used, this is also effectively the last device and the terminating
resistor must be connected (
tr
).
All other technical data and operating instructions are given in
RS 485
Operating Manual
.
USA and Canada:
Use the
MCB 17x conduit box
for the power supply and relay/alarm
contacts. Follow the installation instructions.
Extension of cable between sensor and monitor
In order to extend the cable between sensor and monitor following junction boxes
can be used:
KI/S
passive junction box
KI/pH 170
junction box KI/pH 170 with integrated impedance converter
for high impedance pH electrodes
The maximum distance between the sensor and the monitor, including the length of
the integral sensor cable, is 330 feet.
