Watlow Eurotherm 3508 Quick Start Manual

ENG
3508 and 3504 Process Controllers
This instrument is intended for permanent installation, for indoor use only, and to be enclosed in an
electrical panel.
Select a location where minimum vibrations are present, and the ambient temperature is between 0
o
and 50 C (32 and 122 o F).
The instrument can be mounted on a panel up to 15mm thick.
To assure IP65 and NEMA 12 front protection, use a panel with smooth surface texture.
Please read the safety information before proceeding and refer to the EMC Booklet part number
HA025464. For details not covered in this installation sheet a 3500 User Guide HA033837 is
available. These documents may be downloaded from https://www.eurotherm.com.
Parts Supplied and Dimensions
C D
B A Controller sleeve
A 96mm 3.78inch
B 48mm 1.89in
C 12.5mm 0.5in
Label
A
D 150mm (5.91in)
2.49 resistors are
Latching Terminal block
ears Panel retaining
with covers
clips
Instrument Terminals
3508
Live or 24V
Power
Neutral or 24V
Supply
Ground
Logic I/O A
Digital
Logic I/O B
Inputs/
Logic I/O Com
Outputs
Fixed Relay
(form C)
PV Input
T/C RTD mV mA
Polarising Keys (1). One per module Polarising Keys (1). One per module
HA033839ENG/3 CN41367
Plug in I/O Module Connections
Plug in I/O modules can be fitted in three positions in the 3508 and six positions in 3504. The
positions are marked Module 1, 2, 3, 4, 5, 6. With the exception of the Analogue Input or Dual
DC Output (see below) modules, any other module listed in this section, can be fitted in any of
these positions. To find out which modules are fitted check the ordering code printed on a
label on the side of the instrument. If modules have been added, removed or changed it is
recommended that this is recorded on the instrument code label.
Relay (2 pin) and Dual Relay Module
First relay
Contactor
xA 
Relay Panel Hardware Code: R2 and RR

lamp etc
Rating of relays: 2A, 264Vac max or 100mA, 12V
xB
Voltage
min to provide sufficient wetting current
supply
xC
Contactor
Relay Panel
xD
lamp etc
Second relay (dual relay only)
Change Over Relay
Contactor,
xA
Relay, Panel

Hardware Code: R4
lamp etc
xB

Relay Rating: 2A, 264Vac ma

or 100mA, 12V min to provide sufficient
xC
wetting current.
Voltage
xD
supply
Triple Logic and Isolated Single Logic Output

Hardware Code: TP and LO
+

Outputs Rating: Single logic 12Vdc 24mA
+ Output A
xA

Outputs Rating: Triple logic 12Vdc 9mA
+
SSR or

xB
Output B No channel isolation. 264Vac double
thyristor
+
insulation from other modules and system
unit
Output C xC 
Single Logic Output connections: D –
_
- Common A – Logic Output
xD
Common
Triac and Dual Triac
First triac
Raise

Hardware Code: T2 and TT
xA

Combined Output Rating: 0.7A, 30 to 264Vac
xB 
Voltage
Dual relay modules may be used in place of dual
Motorised
supply
triac.
valve
xC

The combined current rating for the two triacs must
not exceed 0.7A
xD
Lower
Second triac
Installation
B
1. Cut out the panel to the size shown.
A
Panel cut out
3504 controller A x A
92mm (
- 0.0 + 0.8)
A
A
3.62inch
(-0.00, +0.03)
3508 controller A x B
45mm (
- 0.0 + 0.6)
B
1.77inch (-0.00, +0.02)
2. Fit the IP65 sealing gasket behind the front bezel of the instrument.
3. Insert the instrument in its sleeve through the cut-out.
4. Spring the panel retaining clips into place. Secure the instrument in position by holding it
level and pushing both retaining clips forward.
5. Peel off the protective cover from the display.
If the panel retaining clips subsequently need removing, they can be unhooked from the side
with either your fingers or a screwdriver.
To Remove the Controller from its Sleeve
For Ethernet version ensure the Ethernet cables are disconnected from the rear of the
controller (isolate the power supply first).
also supplied for
To remove, ensure that the latching ears are eased outwards, then pull the controller forward,
each mA input to remove from the sleeve. When plugging back in ensure that the latching ears click into
place to maintain the IP65 sealing.
3504 Modules
Power Supply
Caution: Ensure non-isolated modules are never
- Live or 24V
installed in any 3500 Series controller. Non-isolated
- Neutral or 24V
modules are NOT supported.
- Ground
Digital
- Logic I/O A
Inputs/Outputs
- Logic I/O B
- Logic I/O Com
Wiring
Fixed Relay
Wire Sizes: The screw terminals accept wire sizes
(form C)
from 0.5 to 1.5 mm (16 to 22AWG) and should be
tightened to 0.4Nm (3.5lb in). Hinged covers
prevent hands or metal making accidental contact
with live wires.
PV Input
T/C RTD mV mA
02/2024
For module functionality see 'Quick Code'.
The function of the connections varies depending on the type of module fitted in each position
and this is shown below.
Note: The order code and terminal number is pre-fixed by the module number (x). For
example, Module 1 is connected to terminals 1A, 1B, 1C, 1D; module 2 to 2A, 2B, 2C, 2D, etc.

All modules are isolated 240Vac CATII.
Snubbers
Snubbers are used to prolong the life of relay contacts and to reduce interference when
switching inductive devices such as contactors or solenoid valves. The fixed relay (terminals
AA/AB/AC) is not fitted internally with a snubber, and it is recommended that a snubber be
fitted externally. If the relay is used to switch a device with a high impedance input, no
snubber is necessary.
All relay modules are fitted internally with a snubber since these are generally required to
switch inductive devices. However, snubbers pass 0.6mA at 110V and 1.2mA at 230Vac,
which may be sufficient to hold on high impedance loads. If this type of device is used it will
be necessary to remove the snubber from the circuit.
The snubber is removed from the relay module as follows: -
1. Unplug the controller from its sleeve.
2. Remove the relay module.
3. Use a screwdriver or similar tool to snap out the track.
The view shows the tracks in a Dual Relay Output module.
Dual DC Output (Slots 1, 2 and 4 only)

+ Hardware Code: DO
xA

Output Rating: each channel can be 4-
Output 1
-
20mA or 24Vdc power supply)
xB
20V – 30V
+ 4-20mA
xC
-
Output 2
xD
Standard Connections
These are connections which are common to all instruments in the range.
Recommended
PV Input (Measuring Input)
Minimum Spacing
C
1. Run signal cables separately from power cables.
C 10mm (0.4in)
D 38mm (1.5in) 2. When shielded cable is used, it should be grounded at one point only.
3.Any external components (such as zener barriers, etc) connected between sensor and input
D
terminals may cause errors in measurement due to excessive and/or un-balanced line
(Not to scale)
resistance or possible leakage currents.
4.This input is not isolated from logic I/O A and logic I/O B.
3508 3504
Thermocouple or Pyrometer Input

Use the correct type of thermocouple compensating cable, preferably
+ shielded, to extend wiring
V+

It is not recommended to connect two or more instruments to one
V- thermocouple
-
RTD Input

The resistance of the three wires must be the same.

The line resistance may cause errors if it is greater than 22
VI
Note 1: For 2-wire this is a local link.
V+
V-
Note 1
Linear Input V, mV and High Impedance V

mV range +40mV or +80mV

+80mV High level range 0 – 10V
V+

0 – 2V
High Impedance mid-level range 0 – 2V. Used for zirconia probe oxygen
V- input.
0 – 10V

A line resistance for voltage inputs may cause measurement errors.
Linear Input mA

For mA input connect the 2.49 resistor supplied across the input
terminals

V+
0 – 20mA The resistor supplied is 1% accuracy 50ppm temperature coefficient.

4 – 20mA A resistor 0.1% accuracy 15ppm resistor can be ordered as a separate
V-
item. Part No. SUB35/ACCESS/249R.1
Built in Relay (AA)

Relay shown in de-energised state
AA

Isolated 240Vac

Relay rating: Max: 264Vac 2A resistive; min: 1V, 1mAdc to provide sufficient
AB
wetting current.

AC
Relay shown in de-energised state
Plug in I/O Module Connections (continued)
DC Control
Actuator
xA
0-20mA
or
xB
0-10Vdc
DC Retransmission
To other
controllers
xA
0-20mA
or
xB
0-10Vdc
Triple Logic Input
Break out
Input 1 xA
tracks as
required to Input 2 xB
disconnect
xC
the Input 3
snubber.
Common xD
Triple Contact Input
Input 1
xA
External
Input 2
Switches
xB
or Relays
Input 3
xC
xD
Common
Potentiometer Input
xA
+0.5V
xB
xC
xD
0V
Digital I/O
These terminals may be configured as logic inputs, contact inputs or logic outputs in any
.
combination
The Digital IO is not isolated from the PV input. The controller is designed to
operate normally if the input sensor is connected to 240Vac, but in this case these terminals will
be at this potential.
Logic Inputs
LA Input 1
LB Input 2
LC Common
Digital (Logic) Outputs
LA Output 1
LB Output 2
LC Common
The fixed digital logic outputs may be used to power remote 2 wire transmitters. The fixed
digital I/O are, however, not isolated from the PV input circuit, so this does not allow the use of
3 or 4 wire transmitters. An isolated module must be used for the 3 and 4 wire types.
Digital (Logic) Outputs used to power a remote 2 wire transmitter.
Output 1 LA
Output 2
LB
V+
4- 20mA
V-
Digital (Logic) Output modules used to power remote 3 or 4 wire transmitters.
2.49
V+
V-
4- 20mA
Isolated Transmitter Option
24V Transmitter Power Supply
Transmitter

+ Hardware Code: D4

Output Rating: (10Vdc, 20mA max)
-
Transducer Power Suppy
Transducer with Internal Calibration Resistor
Controller

Hardware Code: D6 10Vdc
+

power
Output Rating: (10Vdc, 20mA max)
supply
-
Internal
switch to
connect
Rcal

Hardware Code: TL

Input Ratings: Logic inputs <5V OFF >10.8V ON
Limits: -3V, +30V
V+
mV Input
V-
Transducer with External Calibration Resistor

Hardware Code: TK Controller

Input Ratings: Logic inputs >28K OFF <100
10Vdc
ON
power
supply
Internal
switch to
connect
Rcal

Hardware Code: VU

Rating: 100 to 15K
V+
V-
It is possible to have one input and one output on either channel.
Contact Closure Inputs
Voltage level logic inputs:
LA 
Contact open
Input 1

12V, 5-40mA
>1200

LB Input 2
Logic '1' (Active): >10.8V 
Contact closed

Logic '0' (Inactive): <7.3V
<480
LC Common

The logic outputs are capable of driving SSR or thyristors up to
9mA, 18V. It is possible to parallel the two outputs to supply 18mA,
18V.
2 Wire
The parallel logic outputs supply >20mA, 18V.
Transmitter
Connect the supplied load resistor equal to 2.49 for mA
input.
2.49
+
+ 2.49
3 Wire
4 Wire xA
xA
Transmitter
V+
-
Transmitter
-
xB
xB
V-
4- 20mA
Isolated Transmitter Option
module +24V >20mA module +24V >20mA
+ 
Hardware Code: MS
xA

Output Rating: 24Vdc 20mA
-
xB

Hardware Code: G3

Rating: Configurable 5V or 10Vdc
Transducer
xA 
Minimum load resistance 300
+
White
xB
-
R
CAL
xC
B
xD
V+ Red
Black
V-
A
Green
C
Input if an analogue input module is used
in the appropriate slot.
D
Transducer
White
+
xA
-
xB A
30.1K
xC
Red
Black
V+
V-
xD
B
Green
mV Input