What do the following triangles in the schematic represent?

 

They mean the power Common plane.
Max.

 

They mean the power Common plane.
Max.

Thanks Max,
What exactly does that mean though?

 

I think they are differential digital inputs. One input sets the logic threshold (A2) and the other input is either HIGH or LOW with respect to that threshold.

 

The power negative is generally used as the circuit common plane which is usually symbolized by the inverted triangle symbol, in some cases this can be connected to earth ground and the appropriate symbol is shown for this.
As per the PDF.
In N.A. the earth symbol is often misused as power common when it is actually not at earth ground. Also in N.A. ground is also used to indicate an earth conductor which further confuses the issue.
Max.

 

In stat schematic, the start switch would short the power if A1&A2 are power, so obviously they could be something else.

Commons usually have one wire to them instead of two.

 

Actually taking another look it appears to be a PLC input module which is usually an opto input type, which would make the symbol in this case the two inputs of a Opto IC.
Max.

 

I assume by the IEC symbols you are not in N.A.?
If this is a PLC input, they just show the symbol as a representation of the input, you do not require to know the details.
Max.

 

In stat schematic, the start switch would short the power if A1&A2 are power, so obviously they could be something else.

No, the far left shows a relay coil. So start (a momentary push button) energizes that relay. Stop breaks the circuit and allows the relay to release.



If that is correct, then the triangles are probably a power common, e.g., screw terminals on a bus bar.

John

 

If the OP confirms it is a PLC input then the opto representation makes perfect sense.
But the E-stop P.B. and output 04 N.C. contact actually confirms the power in.
If they were GND symbols the E-stop & 04 contact would short the power.
Input I.4 is a confirmation input.
Max.

 

The ting under A1 could be a thermal breaker although an AC coil is probable too.

 

A1 is the symbol for a fuse/breaker usually.
Found the manual for it and it is a TeSys LTM R unit which is a form of PLC if anyone cares to search.
A1 A2 are the power input, AC or DC.
The unit is a multi drop unit from a Modbus fed system, specifically for 3 phase motor monitoring.
Max.

 

A rectangle with diagonal line is common for the coil of a relay. Maybe that is a European/German practice?



Sources:

http://www.electrical-installation.org/enwiki/Elementary_switching_devices
http://electronics.stackexchange.com/questions/240280/symbol-or-marking-on-safety-relay

The squiggle is not so common, but neither is that combination for a fuse. I assume that the squiggle meant an AC coil. With the START and STOP buttons, a relay makes sense. Can you show any examples of fuses that match that symbol?

John

 

Those are common IEC symbols, looking at the manual, it also appears to be used to indicate either AC or DC input, which the unit is according to the manual, in this case it seems a loose use of the symbol.
It is a amalgam of the symbols used on a AC/DC power source that can be either AC or DC.
The circuit is from the power through the output relay contact trough the E-stop P.B., both OR'd to an input, IOW an input monitoring the E-stop String, .
This apparently is not a common variable use PLC, but a Motor monitor specialized one.
The manual also states that the input block is just a symbolic representation of the inputs.
Max.

 

Page from the manual.
Max.

 

What do the following triangles in the schematic represent?

They are voltage comparators. They compare the inputs to a reference level on A2.

 

Did you very this as a fact?
Most of the PLC's I use are opto's input and can be configured either sink or source.
See the bottom of page 30-2.
Max.

 

They mean the power Common plane.
Max.

They don't conform to that standard.

Once I worked for a company who's drawing office only knew mechanical engineering symbols......................................

 

They don't conform to that standard.

Once I worked for a company who's drawing office only knew mechanical engineering symbols......................................

I corrected myself in post #7??
Inverted triangle is the Logic common symbol.
Max.

 

What do the following triangles in the schematic represent?

Either op amps or comparators.