Matrox 4Sight EV6 - Migrating Output to Sinking Device

Migrating an auxiliary output wired to a sinking field device that relies on a pull-up resistor 99
These changes improve the immunity of the unit, and optionally allow
maintaining an electrical isolation between all interfaced field devices. This
implementation requires that each auxiliary input/output is referenced
independently, unlike the Matrox 4Sight GPm auxiliary inputs/outputs that only
needed a single negative pin to be used as a reference for all of the auxiliary
inputs/outputs.
The following connections should still operate seamlessly:
• Interfacing Matrox 4Sight EV6 auxiliary inputs to sourcing devices that were
previously interfaced to Matrox 4Sight GPm auxiliary inputs using a 24 V
reference voltage, without connecting external resistors.
• Interfacing Matrox 4Sight EV6 auxiliary outputs with sourcing devices that were
previously interfaced to Matrox 4Sight GPm auxiliary outputs using a 24 V
reference voltage. Sourcing devices must meet specifications for 24 Vdc digital
inputs of either type 1, 2, or 3 as per the EN 61131-2:2007 standard.
 Note that interfacing Matrox 4Sight EV6 auxiliary inputs/outputs with any
wiring involving the presence of external resistors requires proper verifications.
Migrating an auxiliary output wired to a
sinking field device that relies on a pull-up
resistor
To guarantee that a Matrox 4Sight EV6 auxiliary output can reliably replace a
Matrox 4Sight GPm auxiliary output, wired to a sinking field device, the device
must meet the specification of industrial 24 V
dc
digital inputs of either type 1, 2,
or 3, as per the EN 61131-2:2007 standard. If this is not the case (that is, the
sinking field device V
LMAX
threshold is below 3.0 V), the voltage drop across the
Matrox 4Sight EV6 auxiliary output might prevent the sinking field device from
recognizing a low logical state when the output is closed.
To migrate a sinking field device whose V
LMAX
threshold is below 3.0 V, you can
either re-wire the device in a typical complimentary sourcing-to-sinking
connection, or you can add a serial resistor between the AUX_OUTn- and INPUT
pins. Adding a serial resistor will limit the current circulating through the sinking
field device, which means you will need to consider the total voltage drop across