3
Assembly, Commissioning, Periodical Tests
1. Check the resistance. In the non-activated state between 8.1 kOhm and
8.6 kOhm (typical 8.2 kOhm).
2. Check the wiring. F1 (ESR26: F1 and F2) fitted with max. 2 A slow blow?
3. Switch on the unit. When operational the green LED illuminates (with
ESR26 both green LED’s)
4. Activate the signal transmitter. The corresponding yellow LED illuminates
(with ESR26 both yellow LED’s) and the output relay de-energises.
5. The red LED (with ESR26 both red LED’s) illuminates and the output relay
deenergises when a terminal of the signal transmitter is not connected.
Important:
Assembly and wiring according to local regulations. The minimal
cross-sectional area is 0.14 mm
2
. May only be installed in a IP54
housing.
For periodical testing, the contacts J1 and J4 (with ESR26 J2 and J3) must
be bridged consecutively (see Layout). Each time a Stop must occur. The test
«interruption» is achieved by disconnecting the signal transmitter. Stop must
occur.
We recommend that the tests be documented.
The tests are to be carried out by trained personell using a tool with
insulated handle.
ESR25/26
Switching Units
Operating Instructions
ENGLI
SH
209491S
06/16
General
The difference between the ESR25 and ESR26 is that the ESR26 has two se-
parate evaluation circuits.
Function
Connected sensors are monitored with a terminating resistance of 8.2 kOhm
to detect changes in the constant flowing zero-signal current. Both relays are
energised in the non-active condition.
If one or more sensors are activated
• the total resistance drops towards zero ohm
• when the resistance falls below the defined limit (2 kOhm)
• the relays de-energise
• the yellow LED illuminates
When a fault occurs in the sensor circuit (cable breakage, sensor defect…)
• the total resistance increases
• when the resistance exceeds the defined limit (9 kOhm)
• the relays de-energise
• the red LED illuminates
Status LED
Supply
Function
green yellow red
Output
Off
open
On
ready
closed
On
one sensor activated
open
On
short-circuit or test
open
On
cable breakage
open
Connection
• max. total length of sensor with cable 50 m
• max. total area of sensor 5 m
2
• multiple sensors are connected in series
• the total resistance must not exceed 8.2 kOhm
Important:
– The installed fuse is absolutely neccesary. It protects the relay
contacts against «welding» when overloaded.
– Suppressors (220 Ohms/0.1 uF) are to be connected across the in-
ductive loads.
– Periodical function test are to be made.
The designated test contacts are to be bridged (see Layout).
The protection of the unit will be endangered by non-adherence of
these operating manual instructions.
The user acts at his own risk!
Block Diagram
Sensor 1
22(5)
32(8)
R1
R3
24(7)
34(9)
A1(2)
A2(10)
Supply
Voltage
Sensor 2
or 8.2kOhm resistance
F1
11(1)
Drive
Circuit
21(6)
ESR25
• two parallel sensor inputs
• safety output
• supply voltage 24 VACDC
• redundant evaluation of the sensor
ESR26
• two separate sensor inputs
• two separate safety outputs
• supply voltage 24 VACDC
• redundant evaluation of both channels
Sensor 1
22(5)
32(8)
R1
R3
R2
R4
24(7)
34(9)
A1(2)
A2(10)
Supply
Voltage
Sensor 2
F1
F2
11(1)
Drive
Circuit 1
Drive
Circuit 2
21(6)
14(3)
12(4)
