17
Cypress Suprex® RS-485 Series - Using the Remote Digital Relay Inputs
This section applies only to the Remote unit, as the Central unit has only digital relay inputs. DIP
switch 2 controls whether the Remote unit uses the analog relay inputs or the digital relay inputs. By
default, DIP switch 2 is off and the Remote unit is set to use the analog relay inputs. When DIP switch
2 is in the ON position, the Remote unit is set to use the digital relay inputs. The digital relay inputs
function in the same way the analog inputs on the Remote unit function. The digital relay inputs simply
need to be connected to ground for the corresponding relay to be activated.
To active the digital relay inputs, only DIP switch 2 on the Central board needs to be enabled. DIP
switch 2 on the Remote board has no function. It may be necessary to power-cycle the Central unit for
the change to take effect.
Note: The digital relay input pins are not the same Relay 3 and Relay 4 input pins labeled on the
Remote unit. Instead, the digital relay input pins use the two “Not Used” pins on the 10 pin header. The
“Not Used” pin on the outside of the board is the new Relay 3 input pin, the other “Not Used” pin is the
new Relay 4 input pin. Use the diagram below as a reference.
For most applications the analog relay inputs are sufficient. But for instances where a significant delay
is noticed in the activation of Relay 3 and Relay 4, the end user should switch to using digital relay
inputs. The digital relay input pins are able to detect a signal change faster than the analog inputs are,
and this may eliminate the delay in the activation of the relay.
Note regarding EXP units:
While DIP switch 2 is on and the digital relay input pins are enabled on
the SPX-7500 units, the digital relay inputs are also enabled on any EXP-2000 Remote units that are
connected. The digital relay input pins are on the 12 pin header and are the two “Not Used” pins. The
outside “Not Used” pin is the Relay 3 Input pin and the other “Not Used” pin is the Relay 4 Input pin.
+8 to +16 VDC
Ground
exp(+)
exp(-)
+5V Out
Relay 4 Input
Relay 3 Input
LED Out
D1/Data In
D0/Clock In
Relay 2 N.O.
Relay 2 Com
Relay 2 N.C.
Relay 1 N.O.
Relay 1 Com
Relay 1 N.C.
Ground
Aux Input
Not Used
Not Used
+8 to +16 VDC
Ground
exp(+)
exp(-)
+5V Out
Not Used
Not Used
LED Out
D1/Data In
D0/Clock In
Relay 2 N.O.
Relay 2 Com
Relay 2 N.C.
Relay 1 N.O.
Relay 1 Com
Relay 1 N.C.
Ground
Aux Input
Relay 4 Input
Relay 3 Input
DIP Switch 2 Off
(Analog Inputs)
DIP Switch 2 On
(Digital Inputs)
Analog and Digital Relay Input Pins
Remote
Remote
