Hi All,

Hi,

I bought a new Honeywell DT7550UK2 last week to replace an existing
faulty one. The existing one is a DT7550UK so assume this must be the
older version.

Looking at the existing wiring, it is wired as follows
F1 - empty
F2 - empty
T1 - resistor to C
T2 - yellow
C - resistor back to T1 and to NC
EOL - empty
NC - resistor to C and blue
V- - black
V+ - Red

Both resistors have the following bands (Brown, Black, Black, Brown,
Brown) or I guess could be (Brown, Brown, Black, Black, Brown)? If I
have it right, the 1st option would put it as a 1K resistor.

Looking at the installation instructions for the new one, it implies I
should not use the existing resistors as they are built in. Also, it
seems to have Jumpers to set the EOL Value (I assume this has
something to do with the resistors?) with the factory settings being
1K.

Does anyone know anything about this PIR? Should I stick to the
factory settings and remove the resistors and wire up as the current
one?

All help appreciated.

thanks

Lee.

In article ,
Lee Nowell writes:
Hi All,

Hi,

I bought a new Honeywell DT7550UK2 last week to replace an existing
faulty one. The existing one is a DT7550UK so assume this must be the
older version.

Looking at the existing wiring, it is wired as follows
F1 - empty
F2 - empty
T1 - resistor to C
T2 - yellow
C - resistor back to T1 and to NC
EOL - empty
NC - resistor to C and blue
V- - black
V+ - Red

Both resistors have the following bands (Brown, Black, Black, Brown,
Brown) or I guess could be (Brown, Brown, Black, Black, Brown)? If I
have it right, the 1st option would put it as a 1K resistor.

So your panel (this zone at least) is configured for dual-EOL resistors.
The values of the dual-EOL resistors are panel-specific, but 1k
is a value which is used in some cases.

Looking at the installation instructions for the new one, it implies I
should not use the existing resistors as they are built in. Also, it
seems to have Jumpers to set the EOL Value (I assume this has
something to do with the resistors?) with the factory settings being
1K.

Does anyone know anything about this PIR? Should I stick to the
factory settings and remove the resistors and wire up as the current
one?

Your current circuit is dual-EOL resistors (which can signal ALARM or
TAMPER back to the panel). The new PIR can also signal FAULT, but I
don't know if your panel can receive 3 signals on that zone, or just 2.
It's up to you if you use the internal resistors or the existing ones,
but you can't really use the FAULT signal without knowing more about
the panel, and it's interesting that the FAULT signal isn't used in the
existing PIR either.

By the way, I don't like that the PIR remains non-operational after
power-up until you've done a walk test. I've not seen that limitation
in dual-tech motion sensors before.

Also, don't know if your current sensor has anti-masking, but it can
cause a mask alarm if the building has walls/windows which can pass
microwave, so the microwave sees through walls/windows when then PIR
can't. Don't set the microwave sensitivity too high, and do check it
can't see through walls/windows.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Oct 9, 12:19*pm, (Andrew Gabriel)
wrote:
In article ,
* * * * Lee Nowell writes:









Hi All,

Hi,

I bought a new Honeywell DT7550UK2 last week to replace an existing
faulty one. The existing one is a DT7550UK so assume this must be the
older version.

Looking at the existing wiring, it is wired as follows
F1 - empty
F2 - empty
T1 - resistor to C
T2 - yellow
C *- resistor back to T1 and to NC
EOL - empty
NC - resistor to C and blue
V- - black
V+ - Red

Both resistors have the following bands (Brown, Black, Black, Brown,
Brown) or I guess could be (Brown, Brown, Black, Black, Brown)? *If I
have it right, the 1st option would put it as a 1K resistor.

So your panel (this zone at least) is configured for dual-EOL resistors.
The values of the dual-EOL resistors are panel-specific, but 1k
is a value which is used in some cases.

Looking at the installation instructions for the new one, it implies I
should not use the existing resistors as they are built in. *Also, it
seems to have Jumpers to set the EOL Value (I assume this has
something to do with the resistors?) with the factory settings being
1K.

Does anyone know anything about this PIR? Should I stick to the
factory settings and remove the resistors and wire up as the current
one?

Your current circuit is dual-EOL resistors (which can signal ALARM or
TAMPER back to the panel). *The new PIR can also signal FAULT, but I
don't know if your panel can receive 3 signals on that zone, or just 2.
It's up to you if you use the internal resistors or the existing ones,
but you can't really use the FAULT signal without knowing more about
the panel, and it's interesting that the FAULT signal isn't used in the
existing PIR either.

By the way, I don't like that the PIR remains non-operational after
power-up until you've done a walk test. I've not seen that limitation
in dual-tech motion sensors before.

Also, don't know if your current sensor has anti-masking, but it can
cause a mask alarm if the building has walls/windows which can pass
microwave, so the microwave sees through walls/windows when then PIR
can't. Don't set the microwave sensitivity too high, and do check it
can't see through walls/windows.
he
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Hi Andrew,

Thanks very much for your help. I wasn't sure which way around to read
the resistors. Do you know whether they are/ would be 1k? Yes,
current PIR is the same with microwave detection etc.

It seems easier to use the internal ones then and I can ditch the
current ones. Am I safe enough to rewire it with the power on? My
theory was that it is still live if I switch the power off given the
battery back-up.?

Thanks once again

Lee.

In article ,
Lee Nowell writes:
Hi Andrew,
Thanks very much for your help. I wasn't sure which way around to read
the resistors. Do you know whether they are/ would be 1k? Yes,

Brown, Black, Black, Brown, Brown is 1k with 1% tolerance.
1% tolerance seems unnecessarily expensive for this application.

current PIR is the same with microwave detection etc.
It seems easier to use the internal ones then and I can ditch the
current ones. Am I safe enough to rewire it with the power on? My

Probably not a good idea unless you're well skilled. If you short
the power out, you might blow a fuse in the panel (although my panel
uses PTC fuses which self-reset, not all do). If you accidentaly
touch the supply against the wrong part of the PIR, you might wreck
it.

theory was that it is still live if I switch the power off given the
battery back-up.?

Yes, you'd need to disconnect the battery, or there might be a fuse
in the panel to disconnect supply to external sensors. You'll also
need to know how to powerup the panel from scratch, e.g. if there's
any specific procedure required, such as the Engineer's code.
Hopefully the panel will keep all its config in NVRAM, but things
can go wrong. I did once manage to complete clear the NVRAM in mine
by mistake, but fortunately I had a backup of its contents. I just
had to quickly write an uploader so I could load the programming
back in.


One other thing - where did you buy it?
I used to buy from CPC - 10+ years ago they had a superb range of
alarm sensors available at very reasonable prices. Today, their
range is very limited.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]