4 test tables for passive barriers – Dwyer MTL7787 User Manual
Page 18
14
INM7700-6 Jan 2010
BARRIER DATA
MULTIMETER TESTS
CONSTANT-CURRENT TESTS
MTL
Safety
End-to-end
Diode
Diode
Terminal
Terminal
model
Description
Resistance
Test
Test
Voltage
Voltage
No.
Ω
Ω
+ve
-ve
@ 10
μμA
@ 20mA
V
Ω
Ω mA Min Max
Min
Max
Min
Max
7710+
10 50 200
62
75
∞
Vf
z
x 1
6
9.5
6.6
9.7
7715+
15 100 150
110
119
∞
Vf
z
x 1
12
13.6
12.4
13.7
7715P+
15 50 291
59
64
∞
Vf
z
x 1
12.6
13.3
13
13.4
7722+
22 150 147
159
174
∞
Vf
z
x 2
19.6
20.9
19.7
21.1
7728+
28 300 93
311
333
∞
Vf
z
x 2
25.9
26.5
26
26.7
7728-
28 300 93
311
333
Vf
z
x 2
∞
25.9
26.5
26
26.7
7728P+
28 237 119
241
252
∞
Vf
z
x 3
24.9
25.5
25
25.6
7729P+
28 164 170
171
184
∞
Vf
z
x 3
24.9
25.5
25
25.6
8.4
Test tables for passive barriers
Tables 4 to 10 detail the tests for all MTL7700 Series ‘passive’ barriers. In the ‘diode test’ columns, the figures adjacent to the diode description
indicate the number of forward-biased diodes used in the barrier chain. Using the multimeter diode test function and knowing the diode voltage
drop figures (approximately 0.6V for each Zener diode and 0.3V for each Schottky diode), the expected reading across the diode chain can
be determined.
BARRIER DATA
MULTIMETER TESTS
CONSTANT-CURRENT TESTS
MTL
Safety
End-to-end
Diode
Diode
Terminal
Terminal
model
Description
Resistance
Test
Test
Voltage
Voltage
No.
Ω
Ω
+ve
-ve
@ 10
μμA
@ 20mA
V
Ω
Ω mA Min Max
Min
Max
Min
Max
7758+
7.5 10 750
14
17
∞
Vf
z
x 1
6
6.9
6.6
7
7758-
7.5 10 750
14
17
∞
Vf
z
x 1
6
6.9
6.6
7
7764+
12
1k
12
1010 1050
∞
Vf
z
x 1
10
11.4
10.5
11.6
7767+
15 100 150
110
119
∞
Vf
z
x 1
12
13.6
12.4
13.7
7779+
28 300 93
311
333
∞
Vf
z
x 2
25.9
26.3
26
26.5
7796+
26 300 87
311
333
∞
Vf
z
x 2
23.9
24.4
24
24.6
7796+ (ch2)
20 390 51
401
428
∞
Vf
z
x 2
18.3
18.8
18.4
19
7796-
26 300 87
311
333
Vf
z
x 2
∞
23.9
24.4
24
24.6
7796- (ch2)
20 390 51
401
428
Vf
z
x 2
∞
18.3
18.8
18.4
19
7788+
28 300 93
311
333
∞
Vf
z
x 2
25.9
26.4
26
26.6
7788+ (ch2)
10 50 200
62
75
∞
Vf
z
x 1
6
9.5
6.6
9.7
7788R+
28 300 93
311
333
∞
Vf
z
x 2
25.9
26.4
26
26.6
7788R+ (ch2) 10 50 200
62
75
V
r
V
r
0
0
6.2
6.8
Table 4: Single channel polarised barriers
Table 5: Dual channel polarised barriers
Note:
Vf
z
is the voltage dropped by a forward biased zener diode - 0.6V typically
V
r
is the voltage dropped by the sense and current limit resistors - 3.2V for a typical 1mA test current