Dwyer MTL7787 - Manual (Page 17)

13 INM7700-6 Jan 2010
Input Output Line Fault
Open circuit Open Closed
Short circuit Closed Closed
620 Ω Closed Open
10K Ω Open Open
8.3.3.2 Testing MTL7742 Barriers
The MTL7742 is a single channel switch/prox input barrier with an
open collector solid state interface to the safe area equipment. To
verify correct operation proceed as follows:
a) Connect the barrier as shown in figure 27.
b) Check that the LED is on when the input switch is closed, and off
when the input switch is open.
8.3.3.3 Testing MTL7743 Barriers
The MTL7743 is a dual channel switch/prox input barrier, each
channel with a relay interface to the safe area equipment. To verify
correct operation proceed as follows:
a) Connect the barrier as shown in figure 28.
b) With an ohmeter, check that the output contacts (terminal 1 & 2)
close when the input switch for channel 1 is closed.
c) Repeat the procedure for channel 2.
8.3.3.4 Testing MTL7744 Barriers
A dual channel version of the MTL7742, this module provides two
solid state interfaces for prox/switch inputs. To verify correct
operation proceed as follows:
a) Connect the barrier as shown in figure 29.
b) Connect power via the power bus
c) Check that the LED is on when the input switch is closed for
channel 1, and off when the input switch is open for channel 1.
d) Repeat the procedure for channel 2.
8.3.3.5 Testing MTL7745 Barriers
This module is a single channel interface for prox/switch inputs with
line fault detection. To verify correct operation proceed as follows:
a) Connect the barrier as shown in figure 30.
b) With an ohmeter, check the status of the output contacts
according to Table 3
3
4 1
2
MTL7742 5
6
7
8
Bussed Power
24V
Vs+
Vs- }
2KΩ
Figure 27: Test circuit for MTL7742
3
4 1
2
MTL7745 5
6
620W 10kW
24V
Bussed Power
Line Fault
Output
Vs+
Vs–
Figure 30: Test circuit for MTL7745
Table 3 Test conditions for MTL7745
3
4 1
2
MTL7743 5
6 7
8
Bussed Power
24V
Vs+
Vs–
Channel 1
Channel 2
Channel 1
Channel 2
Figure 28: Test circuit for MTL7743
3
4 1
2
MTL7744
5
6 7
8
Bussed Power
24V
Vs+
Vs-
2KW 2KW
Channel 1
Channel 2
Channel
1
Channel
2
Figure 29: Test circuit for MTL7744
8.3.3 Tests for MTL774x
The MTL774x range are switch/prox input barriers with a choice of
changeover relay contacts or a solid state switch acting as the safe
area interface. Relay contacts provide a universal interface capable
of switching a wide range of signals including ac, low level and high
level voltages. Phase reversal is achieved by connecting the normally
open or normally closed contacts as required. The solid state switch
variants can be configured to switch from a power rail or down to
ground and makes these barriers ideal for high switching frequency
applications.
When testing bus powered barriers use either an MTL7798 Power
Feed module or an MTL7799 dummy barrier for direct ‘feed-through’
connection of a 24V dc supply.
8.3.3.1 Testing MTL7741 Barriers
The MTL7741 is a single channel switch/prox input barrier with
changeover relay contacts acting as the safe area interface. To verify
correct operation proceed as follows:
a) Connect the barrier as shown in figure 26.
b) With an ohmeter, check that the output contacts (terminal 5 & 6)
close when the input switch is closed.
3
4 1
2
MTL7741
5
6 7
8
Bussed Power
24V
Vs+
Vs–
Output
Figure 26: Test circuit for MTL7741