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You are
quite right about the output voltage of the G4REG, its more or less the same
for all of the Opto22 I/O families.
G4REGs are not user adjustable. But as well as checking the output
voltage maybe you should be monitoring your supply input voltage input should
be 24VDC +/.0,1V. I would be surprised if the problem in within the G4REG's
Here are a few
questions that you might not have considered.
- How regulated is the 24V
supplying the G4 Mistic Bricks.
The specification is 24VDC +/- 0,1V. Could it be that the G4REG output voltage is unstable simply because
the input supply is unstable?
- Is the 24VDC supply to your G4
Mistic Bricks in series (i,e daisy chained like the comms) or in star
(individual cables to all bricks form the power supply)?: Mistic bricks
should always use “star” connection
- How close are your 24VDC power
supply’s running to maximum wattage.
Each G4A8R analog brick consumes 4.32W, G4RAX consumes 1.56W and
each G4D16R consumes 6W. To this
you still have to add the consumption of the I/O modules (Check Specsheets
for details) and also any transmitters or valves being powered by the
analog mistic bricks. (see point 5)
- Are you using 24VDC G4IDC5 and
G4ODC5 Optos. Its always better to
use two separate isolated power supplies, one for the mistic bricks and
another separate general purpose supply for the field circuits. Otherwise spikes and earth problems in
the field can easily end up at the G4REG input.
- How are you supplying analog
field devices from G4AD3 and G4DA3.
If you are powering from the brick (System Powered Option) and have
impedance devices, this can cause damage to the G4REG or exceed their
capacity. Its recommendable to use
separate supplies (see point 4) to avoid field problems bypassing the
normal G4 module isolation through the “backdoor” of the G4REG which is
transformer isolated.
- Make sure the mistic bricks are
properly mounted in a suitable cabinet and that the comms cable is
shielded and run separately from mains voltage cabling. Make sure they are a safe distance from
AC power transformers, 3 phase equipment and variable speed drive units
all of which generate uncontrolled levels of RFI.
- With what frequency is this problem occuring and what does it coincide with? Could it be a software problem after all, (illegal function call, command not correctly sopported in latest level of controller firmware etc)
With
respect to the TX/RX LEDS on the brick.
Normally a controller will retry any unanswered transmission a number of
times (I think its 16, maybe somebody could confirm it) and then mark the
mistic brick as incommunicable. Unless
your program application has some logic to reenable comms, the controller will
not transmit further request messages, and therefore the brain will not answer.
Maybe there is a clue there somewhere. If you have multiple brains on a single
comms line you should still be receiving a RX light on the brain as it
continues to receive transmissions for other brains.
When talking through this problem you will
need to supply an system architecture diagram. It may need
the attention of a system specialist to visit and fully understand whats really
happening in real time. That’s what
your local Opto22 distributor is there for. Some things you just can’t see on the phone!
In general
terms Mistic I/O is probably the most rugged I/O system ever produced by
Opto22. The more filthy the conditions,
the worse the temperature extremes, the better it works. One customer told me the only time he had
problems with his Mistic I/O was when he tried to clean the accumulated layer
of dirt and dust on top. Many of our customer have Mistic I/O running 24/7 for
over 15 years in extreme conditions. I certainly wouldn’t recommend changing it out, although you
should consider upgrading your controllers to SNAP-PAC-S1/S2 controllers to use
the latest software and benefits of Ethernet integration. Its been a good 5 years since IOProject/PACProject took over from FactoryFloor ! You will be surprised at what Opto22 have added since then, while still maintaining support for previous generation hardware and software.
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