Emerson XM679 - How to Enable a Pressure Probe to Share Across the LAN

RS485 Net Monitoring Temperatures Pressure Transducer Setup (XM679 Only) • 35
20.5.RS485 Net Monitoring
Temperatures
20.5.1.RS485 Connection
Sharing a single pressure transducer across multiple
controllers on a LAN:
The parameter (Adr) al
so defines the number of
configurations on the RS485 network (besides the
LAn); its value must be only from 1 to the total
number of devices present on the RS485 and the LAN
networks.
Press for three (3) seconds, the rtC or
other will be shown. The measurement
unit blinks.
Press more than once the DOWN arrow to
find the Adr parameter, then press SET.
Set the value of Adr parameter, then press
SET to confirm the parameter.
Press the two keys together to exit from
the menu or wait for about 10 seconds.
20.6.How to Enable a
Pressure Probe to
Share Across the LAN
1. Enter the Pr1 level. Follow the steps in Section 3.7.,
How to Enter the Parameters List PR1.
2. Select Pr2 parameter and press the SET key.
3. The PAS flashing message will display, followed
shortly by “0 --” with a flashing zero.
4. Use the UP or DOWN button to input the security
code in the flashing digit. Confirm the security code
by pressing SET. The security code is 321.
5. If the security code is correct, the access to Pr2 is
enabled by pressing SET on the last digit.
6. Navigate to the LPP of the Master device (the
device where the pressure probe is connected) and
select (Y). Set the LPP to (N) for all other slave
devices.
7. Navigate to tPP of the Master device and set it to
PP (Pressure Probe). The slave devices tPP
parameter will be set to LAn.
8. Navigate to P5C parameter (Pressure Probe will
always be assigned to P5C) of the Master device
and set it to Pressure Probe type. The slave devices
P5C parameter will be set to nP (No Probe).
1. Terminals -36 and +37
2. Use Belden cable #8761
or #8641.
3. Keep at a maximum
distance of
approximately 1Km.
4. Don’t connect the shield
to the earth or to GND
terminals of the device.
Avoid accidental contact
by using insulating tape.
Figure 20-2 - Sharing a Pressure Transducer Between Devices
on LAN
CAUTION! Do not connect the RS485 cable to
all the instruments that are already connected
on the LAN - only connect the RS485 to the
master device of the LAN.
CAUTION! The same value of the Adr
parameter in different controllers creates
malfunctioning in the monitoring system or
problems on the synchronized defrosts.
Shielded Serial Cable
LAN LAN
Shielded Serial Cable
NOTE: If pressure is not being shared across
the LAN, each XM679 will need its own
Pressure Transducer. Please reference Figure
18-1 and Figure 19-1 wiring diagrams.