5 Application Examples
The following 2 examples show the possibilities when
using the VLT
®
PTC Thermistor Card MCB 112.
Example 1: Standard use
130BA966.13
Digital Input
PTC
Sensor
Non-Hazardous Area
Hazardous
Area
X44/
PTC Thermistor Card
MCB 112
1 2 3 4 5 6 7 8 9 10 1112
DI
DI
Safe Stop
12 13 18 19 27 29 32 33 20 37
e.g. Par 5-15
Par. 5-19
Terminal 37 Safe Stop
Illustration 5.1 Standard Use of MCB 112
Parameter 5-19 Terminal 37 Safe Stop
[4]
PTC 1
Alarm
If the motor temperature is too high, or if a PTC
failure occurs, the MCB 112 activates the STO.
Terminal 37 goes LOW (active), and digital input
33 goes HIGH (active). This parameter decides the
consequence of the Safe Torque Off (STO). With
this selection, the frequency converter coasts and
the LCP displays
Alarm 71 PTC 1 Safe Stop
. Reset
the frequency converter manually from the LCP,
digital input, or fieldbus when the conditions of
the PTC are acceptable again (temperature of
motor has dropped).
5-15 Terminal 33 Digital Input
[80] PTC
Card 1
Connects the digital input of terminal 33 in the
FC 302 to the MCB 112, which enables MCB 112
to indicate when STO has been activated from
here.
Table 5.1 Programming Example 1
Alternatively,
parameter 5-19 Terminal 37 Safe Stop
could be
set to
[5] PTC 1 Warning
, which means an automatic restart
when the conditions of the PTC circuit have returned to
acceptable. The selection depends on customer demands.
Example 2: Combination with other components using
STO
130BA967.12
Digital Input
PTC
Sensor
Non-Hazardous Area
Hazardous
Area
X44/
PTC Thermistor Card
MCB 112
1 2 3 4 5 6 7 8 9 10 1112
Safety Device
Manual Restart
SIL 2
Safe AND Input
Safe Output
Saf
e I
nput
DI
DI
Safe Stop
Par. 5-19
Terminal 37 Safe Stop
12 13 18 19 27 29 32 33 20 37
e.g. Par 5-15
Illustration 5.2 More Safety Devices in Combination with STO
and MCB 112
Application Examples
Operating Instructions
MG33V302
Danfoss A/S © 01/2015 All rights reserved.
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