All Questions
11
questions
0
votes
1
answer
32
views
PLC is 2 - 5 VDC and relay works only at 16 - 24 VDC?
I got a panel where the PLC output has 2 - 5 VDC and the relay connected to it says 24 VDC, it will not work below 16 VDC. What's the deal here, aren't PLCs usually 5 VDC? Was the PLC supposed to be ...
- 11
0
votes
1
answer
69
views
How can I identify this component on a PLC board that has gone bad?
How can I identify this component on a PLC board that has gone bad? Surface mount, unidirectional, G is the designator, 060 (090?)
It measures as an open circuit with a multimeter on a bad board and ...
user298907
5
votes
4
answers
547
views
SPI signal noisy when contactor switches
I created a Raspberry Pico based PLC board which worked perfectly alone, however once I placed it into a distribution box and started switching a fairly large (7.5kW) contactor, the on-board seven ...
- 61
-1
votes
3
answers
1k
views
How to operate a relay (24 VDC 8 mA) from a 4-20mA signal?
I have a PLC that can output a 24 VDC, 4-20 mA signal, but it cannot be turned off - the lowest it can go is 4 mA. I found a relay (J104D2C24VDC.20S, 24VDC, 0.20W) that per the datasheet operates at ...
- 21
-2
votes
1
answer
193
views
Design safety relay with OpAmp
I intend to use a safety relay for my project, however I found industrial safety relay mostly work with 24 VCC and is very big, so I decided to make a safety relay based on my specifications.
What I ...
- 343
1
vote
1
answer
137
views
I need to understand the circuit diagram of a Klöckner Moeller relay output unit
I am working on the automation of an old servo driven feed system for a mechanical power press. I have come across these relay output units from Klöckner Moeller (machine make year 1980`s) pictures ...
- 11
0
votes
1
answer
56
views
Can a contactor be used as a temporal logic bit as in PLC?
I want to design a control logic circuit using relay logic. I want to have a bit as a marker as in PLC. Can I use a contactor for this function and then use auxiliary coils as a latch as in PLCs.
- 310
0
votes
2
answers
4k
views
Switching current vs load current
I am using a safety PLC from Schneider and it is connected to a safety output relay with model number XPSMCMRO0004. The datasheet mentions that the min and max switching current is 20mA to 6Amp ...
1
vote
2
answers
3k
views
safety relays and PLCS
I am having trouble trying to get my head around using safety relays in PLC controlled machinery. I want to install a PLC into a machine that needs upgrading, it is straight forward enough, well i ...
user154045
2
votes
3
answers
233
views
Using PLC for more than 200 relays application?
I'm currently building an application to control over 200 devices in a building. Originally I wanted to use an Arduino and bunch of relays to control them. After asking some questions and such, people ...
- 35
-1
votes
3
answers
3k
views
interchangeable operation of two electric motors without PLC
I have two motors that drive an air compressor. I have a pressure switch to turn the motors on/off.
The sequence I want is:
when pressure switch turns ON - motor 1 starts,
when pressure switch turns ...
- 101