Binary Input Operation - York eco2 050 Installation Operation & Maintenance

BINARY INPUT OPERATION

This section describes the control operation of the
six teen (16) binary inputs. The Binary inputs are also
de scribed in the I/O tables in Table 33.
The unit control is equipped with six teen (16) binary in-
puts. The binary inputs can be classiÞ ed into two types,
control and status inputs. Con trol inputs will be used by
the control to switch control states. For ex am ple, BI #7
(J8, Pin 6), Supply Fan (G), will signal to the control
to turn the sup ply fan ON or OFF. Sta tus inputs will
be used by the control to signal the status of, or prove,
certain safety circuits. For example, BI #11 (J9, pin 9),
Supply Fan Status, will signal to the control when the
Supply Fan is ON and thus prove the operation of the
Supply Fan.
The binary input status is deÞ ned as:
• 24VAC detected by the input - the in put is "pres-
ent"
• No voltage detected by the input or voltage below
the 24VAC detection threshold - the input signal is
"not present"
The fault conditions and responses for all binary inputs
with associated faults are given in Table 33.
BI #1, 2, & 3 - Compressor Circuit #1, 2, & 3 Sta-
tus Inputs
Each refrigeration circuit consists of two compressors
arranged in tandem. For safety, each circuit is equipped
with a "compressor safety chain", which consists of
high and low pressure safeties and overloads for each
com pres sor motor. The electrical contacts for the safe ty
devices in this chain will be connected in series with the
entire circuit connected to a 24VAC source. In a "safe"
state, the electrical contacts from all safety de vic es
will be closed. The "compressor safety chain" for each
compressor circuit will be connected to the following
binary inputs:
• Compressor circuit #1 – BI #1
• Compressor circuit #2 – BI #2
• Compressor circuit #3 – BI #3
High Pressure Switch settings are:
open @ 425 +/- 10 psig
close @ 325 +/- 10 psig
YORK INTERNATIONAL
Low Pressure Switch settings are:
open @ 32 +/- 5 psig
close @ 52 +/- 5 psig
For normal operation, the Compressor Circuit Status
inputs must be present (24VAC to input). During low
ambient conditions, when no compressor is ON, the
Low Pressure safety may be tripped (open) indicating
an unsafe condition. To avoid nuisance errors:
• The control will monitor the Com pres sor Cir cuit
Status inputs only when a compressor from that
circuit is operating.
• When any compressor is started, the control will
ignore the associated Compressor Circuit Status
input for 30 seconds.
• After the 30 second delay, if the status input is not
present for more than 250 ms, the control will de-
en er gize all compressors operating in that cir cuit
and de clare a Comp Safety Trip fault.
• The control will then wait ten (30) min utes be fore
re-energizing the compressors in the tripped cir cuit,
if still required.
Each Compressor Status Circuit input has two trip
counters. Both counters will start at zero.
Counter #1 will:
• Increment by 1 any time a trip occurs.
• Be reset to zero counts if one or both com pres sors
on the circuit are ON for 1 hour without a Comp
Safety Trip.
Counter #2 will:
• Increment by 1 any time a trip occurs and both
com pres sors are operating.
• Be reset to zero counts if both com pres sors on the
cir cuit are ON for 1 hour without a Comp Safety
Trip.
If the count of either Compressor Status counter on a
compressor circuit = 3, the compressors on the circuit
are shut down and locked out and a Compressor Safety
Lockout (Comp Safety L/O) fault is declared.
Compressor Safety Lockout(s) will reset through pow er
cycling of the controller.
FORM 100.50-NOM1 (604)
119
8