Quencharc wiring example, Standard bus eia-485 communications, Modbus rtu or standard bus eia-485 communications – Watlow EZ-ZONE RMH User Manual

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Warning:

ç

Use National Electric (NEC) or other
country-specific standard wiring and
safety practices when wiring and
connecting this controller to a power
source and to electrical sensors or pe-
ripheral devices. Failure to do so may
result in damage to equipment and
property, and/or injury or loss of life.

Note:

Maximum wire size termination and

torque rating:
• 0.0507 to 3.30 mm2 (30 to 12 AWG)
single-wire termination or two 1.31
mm2 (16 AWG)
• 0.8 Nm (7.0 in-lb.) torque

Note:

Adjacent terminals may be labeled
differently, depending on the model
number.

Note:

To prevent damage to the controller,
do not connect wires to unused ter-
minals.

Note:

Maintain electrical isolation between
digital input-outputs, switched dc/open
collector outputs and process outputs

to prevent ground loops.

Warning:

ç

Explosion Hazard – Substitution of
component may impair suitability for
CLASS I, DIVISION 2.

Warning:

ç

Explosion Hazard - Do not disconnect
while the circuit is live or unless the
area is known to be free of ignitable
concentrations of flammable sub-
stances.

Watlow EZ-ZONE

®

RMH Module

30

Chapter 2 Install and Wire

Quencharc Wiring Example

• In this example the Quencharc

circuit (Watlow part# 0804-0147-
0000) is used to protect internal
circuitry from the counter elec-
tromagnetic force from the induc-
tive user load when deenergized.
It is recommended that this or
an equivalent Quencharc be used
when connecting inductive loads
to outputs.

Quencharc

User Load

N

L_

K_

Standard Bus EIA-485 Communications

T-/R-

common

Slot C

T+/R+

98 99

CF CD CE

CZ CX CY

• Wire T-/R- to the A termi-

nal of the EIA-485 port.

• Wire T+/R+ to the B termi-

nal of the EIA-485 port.

• Wire common to the com-

mon terminal of the EIA-

485 port.

• Do not route network

wires with power wires.

Connect network wires in

daisy-chain fashion when

connecting multiple de-

vices in a network.

• A 120 Ω termination resis-

tor may be required across

T+/R+ and T-/R-, placed on

the last controller on the

network.

• Do not connect more than

16 EZ-ZONE RM control-

lers on a network.

• maximum network length:

1,200 meters (4,000 feet)

• 1/8th unit load on EIA-485

bus

RMHx-xxxx-x(A)xx

* All models include Standard

Bus communications

Modbus RTU or Standard Bus EIA-485 Communications

T-/R-

common

Slot C

T+/R+

98 99

CC CA CB

CZ CX CY

• Wire T-/R- to the A termi-

nal of the EIA-485 port.

• Wire T+/R+ to the B termi-

nal of the EIA-485 port.

• Wire common to the com-

mon terminal of the EIA-

485 port.

• Do not route network wires

with power wires. Connect

network wires in daisy-

chain fashion when con-

necting multiple devices in

a network.

• A termination resistor may

be required. Place a 120 Ω

resistor across T+/R+ and

T-/R- of last controller on

network.

• Only one protocol per port

is available at a time: ei-

ther Modbus RTU or Stan-

dard Bus.

• Do not connect more than

16 EZ-ZONE controllers on

a Standard Bus network.

• Maximum number of EZ-

ZONE controllers on a

Modbus network is 247.

• maximum network length:

1,200 meters (4,000 feet)

• 1/8th unit load on EIA-485

bus

RMHx-xxxx-x(1)xx

Modbus-IDA

Terminal

EIA/TIA-485 Name

Watlow Terminal

Label

Function

DO

A

CA or CD

T-/R-

D1

B

CB or CE

T+/R+

common

common

CC or CF

common

Note:

Do not leave a USB to EIA-485 converter connected to Standard Bus with-

out power (i.e., disconnecting the USB end from the computer while leaving

the converter connected on Standard Bus). Disturbance on the Standard

Bus may occur.

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